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How can I set specific zooms/resolutions in Openlayers 3 zoom control?

How can I set specific zooms/resolutions in Openlayers 3 zoom control?


I want to have only specific zooms in my zoom cotrol so the map opens in zoom 3 , when click the zoom in it goes to 6 -> 12 -> 16 and back when zoom out.

How is this doable in OL 3 ?


pretty easy , just didn't find it in documentation api.

var resolutions = [305.74811309814453,76.43702827453613,9.109257068634033,9.554628534317017]; var view = new ol.View({ projection: 'EPSG:3857', resolutions: resolutions, center: center, zoom: 9, minZoom: 9, maxZoom: 16 });

Should I crop photos from a prime instead of using a zoom lens?

I wonder whether using a compact, bright, fixed focal lens instead of a large zoom lens will yield comparable results in terms of light gathering ability and resolution.

I am not interested in negligible lens distortion aspects, and consider perspective to be only determined by subject distance.

  • Sensor resolution on enthusiast cameras readily exceeds the requirements of most users
  • The more common and less expensive type of zooms - variable aperture lenses - let in decreasing amounts of light when zooming (i.e. increasing focal length), just like cropping

Could I compensate for the lack of zoom lens simply by cropping? Will I get similar results, and if not, what is the difference?

Note that this question is similar to this thread, but more focused, and that I have already given some thought about it so that I prepared my own answer. I will accept the best answer in two weeks.


In-depth product analysis – Zoom & Microsoft Teams

This is the second post in a series of blogs examining the security of various Video Conferencing products for business. In this post we examining Zoom and Microsoft Teams. Posts still to come over the next few days will dive into Cisco Webex, Cisco Webex Teams, Google Meet, Bluejeans, Skype for Business, Tixeo, Jitsi Meet & BigBlueButton.

To read about our approach to this analysis, understand the target security model we applied or see a side-by-side comparison of the products reviewed please visit our first post from this series.

If you’re interested in the detail from Zoom or Teams, please read on.

Zoom

Zoom Video Communications is a company based in San Jose, California. The business has been enjoying great success since its creation in 2011, but sales have apparently rocketed with the COVID-19 epidemic. Zoom attempts to differentiate itself with excellent service quality and thus relies on its SaaS model exclusively. Zoom is used as collaborative audio and video solution for users (licensed) of meeting rooms, which allows working internally with colleagues as well as externally with partners, with an innovative interactive interface.

Since the beginning of the COVID-19 pandemic and the implementation of self-isolation measures around the globe, the use of Zoom has grown exponentially (+535%, in the United States alone). Several vulnerabilities and breaches, under the spotlights, have undermined security and trust in the company. Whilst these concerns are warranted, we feel that there has also been a fair amount of hyperbole involved, which was part of our motivation for writing this report.

Zoom 5.0 was released on April 27, 2020 and now supports AES 256-bit GCM encryption. This will be enforced across the board starting May 30 th , 2020 meaning only Zoom clients on version 5.0 or later will then be able to join meetings.

In-meeting security controls are now grouped together under the Security icon on the host meeting menu bar. These controls allow the host to enable or disable the ability for participants to: Screen share, Chat or Rename themselves. Hosts can also “Report a User” to Zoom’s Trust & Safety team, enable the Waiting Room feature whilst already in a meeting, lock the meeting once all attendees have joined to prevent unwanted guests and remove any participants which will then prevent that individual from rejoining the meeting.

Additional safeguards have now been implemented these include:

  • Waiting Room enabled by default.
  • Complex eleven-digit unique meeting IDs are now in place. IDs are also removed from the content sharing window to prevent accidental sharing of meeting information.
  • Meeting passwords are now more complex and enabled by default for most customers. For administered accounts, account admins now have the ability to define password complexity requirements.
  • Meeting Registration & Meeting Authentication allows you to have participants register with their email, name and other details or to enable pre-set profiles to restrict access to authenticated users or from specific email domains respectively.
  • All cloud recordings are encrypted with complex passwords on by default.
  • Audio Watermarks allow Zoom to help identify who recorded a meeting if it is shared without permission.
  • Screen Share Watermarks superimposes a participant’s email address onto shared content in the even a screenshot is taken.
  • Hosts can now select which data center regions they would like their in-meeting traffic to use when scheduling a meeting, and participants can see which data center they are connected to.

Features

The application allows screen sharing to collaborate and share notes, visible to all the participants. You can send messages to all participants with one click. Also, recording conferences on-device or in the cloud is possible.

Zoom integrates with “Personal Information Manager” (PIM) applications like Microsoft Outlook and runs on mobile phones (iOS and Android) or on touch screens to allow as many integrations as possible. It connects to numerous audio and video endpoints. To create and manage a meeting, installing a ‘thick’ (executable) client or a mobile application under Windows, Linux, Android or iOS is necessary. We found installing the product under GNU / Linux to be tricky, however. Attending or scheduling a meeting can also be done through a browser.

Zoom also provides integration with several conferencing hardware solutions for cameras, microphones and screens, via partnerships with selected vendors.

Zoom, unlike many solutions presented here, uses proprietary technology and does not use generally accepted WebRTC standards. WebRTC is an interface allowing communication in real-time online. This standard allows browsers to support voice or data sharing directly from the browser, thereby eliminating specific software or extensions to be set up.

We found Zoom to be a very functional and easy-to-use tool, which has probably contributed to its meteoric rise. It’s available for a wide majority of platforms, including a browser, and does not require specific changes to corporate platforms or networks due to its SaaS operational model. Integration with main email and calendar applications such as Microsoft Outlook or Google Suite is smooth. Zoom also offers accessibility features for all participants, for example by enabling subtitles via Rest APIs. Zoom’s widescale adoption also makes it an attractive choice for businesses wanting to connect with others outside their own organization.

Results table

Encryption
Uses an appropriate encryption algorithm Fully GCM with AES 256 since v5. Not fully proven in production.
Uses a strong encryption key Fully AES-GCM with 256-bit keys
Data is encrypted in transit under normal use Fully However, the encryption keys for each meeting are generated by Zoom’s servers
Data stays encrypted on provider servers Partially Provided that meetings aren’t being recorded.
  • SOC 2 (Type II)
  • FedRAMP (Moderate)
  • TrusARC
  • GDPR, CCPA, COPPA, FERPA and HIPAA Compliant (with BAA)
  • Privacy Shield Certified (EU/US, Swiss/US, Data Privacy Practices)See zoom.us/privacy.
  • Single, visible security settings icon
  • Remove participants
  • Report a user
  • Screenshot watermarking
  • Audio watermarking
  • Share specific applications
  • Information Barriers

Encryption

The solution is available exclusively as SaaS (or hybrid cloud), so customers need to be comfortable with trusting Zoom to protect the infrastructure and respect their data. In hybrid cloud mode, user and meeting metadata are managed on the public cloud, whilst video, voice and data sharing go through the on-premise Zoom meeting connector.

Zoom had previously suggested that its communications were end-to-end encrypted, but closer examination has revealed that this is not strictly speaking the case (using our definition above)[1]. Moreover, Citizen Lab reported that Zoom communications are encrypted using the AES-128 and not the AES-256 previously indicated by Zoom[2]. More problematic for some users, the Zoom AES-128 encryption keys could have been transmitted to third parties, possibly in China.

Zoom has however responded forcefully to address these and other issues and the new 5.0 update, includes upgraded encryption. The new ‘Galois Counter Mode’ (GCM)[3] encryption will use the 256-bit ‘Advanced Encryption Standard’ (AES) algorithm[4], which is considered to be standard, reasonable and appropriate for applications of this kind. A thorough evaluation of Zoom’s implementation of this algorithm is beyond the scope of this review, but it would be fair to assert that Zoom has put the primary historic concerns about its encryption to bed with this update.

Apparently in order to bolster their encryption capabilities, Zoom has announced the acquisition of Keybase. Keybase currently delivers an end-to-end encrypted secure messaging and file sharing platform. Zoom has stated that the acquisition is a key step in their “attempt to accomplish the creation of a truly private video communications platform that can scale to hundreds of millions of participants, while also having the flexibility to support Zoom’s wide variety of uses”. Whilst it is not clear to us at this stage what Zoom’s strategy for this acquisition is, it would appear that the technology would position Zoom very strongly to provide full end-to-end encryption based on proven public key encryption methods at some point in the future.

Authentication

Zoom administrators can enable two-factor authentication using Google Authenticator, Microsoft Authenticator or FreeOTP[5].

According to their website, Zoom single sign-on (SSO) is based on the Security Assertion Markup Language (SAML 2.0[6]). Zoom acts as the Service Provider (SP) and offers automatic user provisioning. You do not need to register as a user in Zoom. It can also work with other Service Providers such as PingOne, Okta, Azure, Centrify, Shibboleth, Gluu, G Suite/Google Apps and OneLogin. Zoom can additionally work with Microsoft’s ADFS 2.0[7] SAML implementation.

Zoom actually offers a native 2FA implementation via various ‘One Time Pin’ applications for mobile, but these are only enforced for authentication to the web interface, i.e. not for joining meetings via the mobile or desktop applications. However the SSO various platforms supported would allow enhanced features like push-to-mobile for strong authentication for all elements of the Zoom ecosystem.

Until recently instant Zoom meetings didn’t enforce a password, meaning that anyone who got the meeting ID could join the ongoing meeting sometimes with funny tricks sometimes with more unethical behavior, but this issue appears to have been addressed by a series of new features culminating in the release of Zoom v5.

It has also been disclosed that Zoom settings would add the same domain email address to a sole directory, which in some cases people using a personal email address could be added to a pool of contacts they know nothing about, sharing their personal information such as email address and photo. As of 18 April Zoom has stated that users will no longer be able to search by full name for contacts with the same domain if they are not on the same account or organization. We believe this change mitigates the issue above.

Regulations and Jurisdiction

Zoom Inc is a registered U.S. company, but media reports have suggested that it is tightly integrated with several Chinese businesses, employs developers in China and indeed has accidentally routed some traffic through servers in China for a small subset of their users. This caused concern and outcry for users and businesses who believed Zoom to fall wholly under US jurisdiction[8].

However, Zoom does have an option under its advanced settings for paid accounts that allow users to opt-out of certain data center regions. Any number of regions can be deselected, except the region from which the account was provisioned. According to Zoom’s site “Datacenter regions selections apply only for meeting and webinar traffic. The selections do not impact the location of data at rest. Datacenter region selections also do not apply to Zoom Phone or related features”[9].

Another feature promoted on Zoom’s website is worth noting. Zoom “Meeting Connector” is a hybrid cloud deployment method, which allows a customer to deploy a Zoom multimedia router (software) within the customer’s internal network. According to their site: “User and meeting metadata are managed in Zoom communications infrastructure, but the meeting itself is hosted in the customer’s internal network. All real-time meeting traffic including audio, video, and data sharing go through the company’s internal network”.

Zoom claims adherence to privacy standards like HIPAA and GDPR and asserts that its policies are designed to reflect their compliance with the requirements of the Children’s Online Privacy Protection Act (COPPA), the Federal Education Rights and Privacy Act (FERPA), the California Consumer Privacy Act (CCPA), and other applicable laws. That appears to be mostly by virtue of the fact that it doesn’t collect the relevant data or obtain user consent before doing so.

Security Features and Management

Zoom offers role-based access control which enables an account to have additional user roles. User roles can have a set of permissions that allows access only to the settings pages a user needs to view or edit.

Zoom’s ‘Admin Management’ portal appears very similar to the advanced settings page a user would work with, but with the added ability to define settings for various subsets of users. An administrator can not only set defaults for these settings but can also opt to ‘lock’ a setting so that it can’t be overwritten by an individual user. Our experience of the interface showed it to be fast, simple and intuitive once properly installed.

The portal also allows admins to view the software versions running for different users, but there doesn’t appear to be a way to centrally manage the client software. According to the Zoom site, “the Desktop Client can be mass configured for Windows in 3 different ways: via the MSI installer for both configuration and installation, an Active Directory administrative template utilizing Group Policy for configuration, or via registry keys for configuration”[10].

Vulnerability and Exploit history

The NIST National Vulnerability Database records six vulnerabilities for Zoom since the beginning of 2019:

Year Reported NVD Total Percentage
2019 3 17,308 0.02%
2020 6 7,519 0.08%

Several of the vulnerabilities counted above would be considered ‘serious’, but at least two are being disputed by Zoom.

The recent vulnerabilities and breaches have attracted a lot of attention and apparently undermined trust in the technology. Here’s a brief summary:

  • Zoom, by apparently misunderstanding the Facebook Software Development Kit (SDK), shared data of iOS users with Facebook for a certain time. Fortunately, these data transfers were stopped after being reported[11].
  • Citizen Lab reported an issue in which Zoom would automatically send a live video stream of the meeting, as well as the meeting’s decryption key, to all users in a meeting’s waiting room[12].
  • Zoom allows you to automatically generate address directories: People working in the same company can group directories. However, there were concerns because Zoom did the same with personal email addresses such as Gmail, exposing hundreds of thousands of email addresses to other third parties[13].
  • A previous version of Zoom for MacOS installed a secret web server, which was not removed when the application was uninstalled. This issue was eventually addressed after some public outcry[14].

However, Zoom seems to understand these security issues and has been aggressively taking necessary measures to address these issues and patch vulnerabilities as soon as possible. The new 5.0 update addresses all the security vulnerabilities known to us at the time of writing, as summarized in the table below.

Topic Source Disclosure Date Resolution date Resolution Description/Link
Attention tracking https://www.vice.com/en_us/article/qjdnmm/working-from-home-zoom-tells-your-boss-if-youre-not-paying-attention 16th March 2020 1st April 2020 Remove feature https://blog.zoom.us/wordpress/2020/04/01/amessage-to-our-users/
Zoom Bombing https://techcrunch.com/2020/03/17/zoombombing/ 17th March 2020 20th March 2020 Best security practices https://blog.zoom.us/wordpress/2020/03/20/keepuninvited-guests-out-of-your-zoom-event/
Facebook SDK https://www.vice.com/en_us/article/k7e599/zoom-ios-app-sends-data-to-facebook-even-if-you-donthave-a-facebook-account 26th March 2020 27th March 2020 Remove FB SDK https://blog.zoom.us/wordpress/2020/03/27/zoom-use-of-facebook-sdk-in-ios-client/
End to End encryption https://theintercept.com/2020/03/31/zoom-meeting-encryption/ 31st March 2020 1st April 2020 Clarification about Zoom encryption https://blog.zoom.us/wordpress/2020/04/01/facts-around-zoom-encryption-for-meetings-webinars/
Microsoft UNC Links https://www.bleepingcomputer.com/news/security/zoom-lets-attackers-steal-windows-credentials-run-programs-via-unc-links/ 31st March 2020 1st April 2020 Software update https://blog.zoom.us/wordpress/2020/04/01/amessage-to-our-users/
Mac Local Privilege https://www.vmray.com/cyber-security-blog/zoom-macos-installer-analysis-good-apps-behaving-badly/ 1st April 2020 1st April 2020 Software update https://blog.zoom.us/wordpress/2020/04/01/amessage-to-our-users/
Routing Data to China https://theintercept.com/2020/04/03/zooms-encryption-is-not-suited-for-secrets-and-has-surprising-links-to-china-researchers-discover/ 3rd April 2020 3rd April 2020 Configuration check https://blog.zoom.us/wordpress/2020/04/03/response-to-research-from-university-of-torontos-citizen-lab/

Sources

[1] https://theintercept.com/2020/03/31/zoom-meeting-encryption/
[2] https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto-a-quick-look-at-the-confidentiality-of-zoom-meetings/
[3] https://link.springer.com/referenceworkentry/10.1007%2F978-1-4419-5906-5_451
[4] https://www.itpro.co.uk/security/29671/what-is-aes-encryption
[5] https://support.zoom.us/hc/en-us/articles/360038247071-Setting-up-and-using-two-factor-authentication
[6] https://en.wikipedia.org/wiki/Security_Assertion_Markup_Language
[7] https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc786469(v=ws.10)
[8] https://www.cnbc.com/2020/04/15/nancy-pelosi-calls-zoom-a-chinese-entity.html
[9] https://support.zoom.us/hc/en-us/articles/360042411451-Selecting-data-center-regions-for-hosted-meetings-and-webinars
[10]https://support.zoom.us/hc/en-us/articles/201362163-Mass-Installation-and-Configuration-for-Windows
[11] https://betanews.com/2020/03/28/zoom-data-sharing-update/
[12] https://citizenlab.ca/2020/04/zooms-waiting-room-vulnerability/
[13] https://digitalguardian.com/blog/zooms-privacy-problems-snowball-two-zero-days-uncovered
[14] https://www.theverge.com/2019/7/8/20687014/zoom-security-flaw-video-conference-websites-hijack-mac-cameras

Microsoft Teams

Microsoft Teams is a proprietary collaborative communication application, operating only in SaaS mode, officially launched by Microsoft in November 2016. The service can be integrated with Microsoft Office 365 suite and Skype for Business. It is also expected to replace Skype, which will be abandoned in July 2021. The solution allows collaborative work (co-publishing and storage of documents, access to e-mails and an instant messaging system, etc.), thus offering far beyond the traditional features of video conferencing systems. Teams also offers extensions that can be integrated into products other than Microsoft.

Microsoft Teams has been available in a free version, limited to 300 members, since July 13, 2018, although some features of Office 365 are missing. The solution now claims more than 44 million active users with an exponential acceleration since the beginning of the massive pandemic-driven teleworking migration in many countries.

Features

The solution is available on most Microsoft Windows, MacOS, Android, iOS and GNU / Linux distributions. The product is completely usable via a browser, with no need to install a client. However, the optional rich client or a fully supported browser (like Microsoft Edge based on Chromium or Chrome itself) is required to access advanced features like content sharing, control of shared content, and background[1].

A free version exists for SMEs (up to 300 users) although it offers very limited functionality. We feel that the solution might be a bit heavy for very basic or occasional needs.

Results table

Encryption
Uses an appropriate encryption algorithm Fully All cipher suites supported by Office 365 use algorithms acceptable under FIPS 140-2. Office 365 inherits FIPS validations from Windows.
Uses a strong encryption key Fully AES-GCM with 256-bit keys
  • SSAE16
  • SOC 1 and SOC 2
  • HIPAA
  • EU Model Clauses (EUMC)
  • Advanced Threat Protection
  • Safe Links
  • Safe Attachments
  • Information Barriers
  • Communications Compliance
  • Data Loss Prevention
  • Share specific applications

Encryption

Teams uses Transport Layer Security (TLS), and mutual TLS (MTLS) which encrypt instant message traffic. Point-to-point audio, video, and application sharing streams are encrypted using Secure Real-Time Transport Protocol (SRTP)[2]. Files are stored in SharePoint and secured by SharePoint encryption. Notes are managed via OneNote and protected by OneNote encryption, also hosted on a SharePoint. Microsoft asserts that with Microsoft O365 data is encrypted in transit and at rest.

Network communications are encrypted. All Teams servers must use certificates and implement technologies like Oauth, TLS or SRTP plus 256-bit encryption. Communications are encrypted from users to Teams servers, meaning they are not encrypted end-to-end[3].

Teams requires all servers to contain at least one Certificate Revocation List distribution point for purposes of verifying that a certificate has not been revoked since the time it was issued.

Microsoft O365 offers an added layer of encryption at the application level called ‘service encryption’, which covers data from Exchange Online, Skype for Business, SharePoint Online, OneDrive for Business, and Teams files[4].

According to Microsoft Tech Community contributor ‘Alexwall’[5], “Microsoft retains an availability key, which means that Microsoft could access all customer data. The lack of encryption of Teams messages, as well as the existence of an availability key for all services, would be a concern for a customer that wants 100% security”[6].

The mobile client supports App Protection Policies from Microsoft InTune that would ensure that its content is encrypted on the mobile endpoint device[7].

Authentication

Authentication is based on Office 365 with Microsoft Azure in particular. Microsoft Teams desktop clients for Windows and Mac support ‘modern authentication’ which brings sign-in based on the Azure Active Directory Authentication Library (ADAL) to Microsoft Office client applications across platforms[8]. Microsoft Teams supports all the identity models that are available with Office 365 and has a comprehensive set of tools for provisioning and managing identities, all tied in with existing Active Directory or Azure implementations.

Multi-Factor authentication is supported with any Microsoft 365 or Office 365 plan that includes Microsoft Teams, with support for phone calls, text, One Time Pin or Mobile App Notification as second factors. Users also benefit from the additional security controls provided by Microsoft across its O365 range of services.

Jurisdiction & Regulation

Teams is categorized by Microsoft as a ‘Tier D’ compliant application, which means it adheres to ISO 27001, ISO 27018, SSAE16 SOC 1 and SOC 2, HIPAA, and the EU Model Clauses (EUMC). Teams is also German government BSI Cloud Security Alliance compliant.

For new customers only, data in Teams resides in the geographic region associated with the customer’s Office 365 organization. Currently, Teams supports the Australia, Canada, France, Germany, India, Japan, South Africa, South Korea, Switzerland (which includes Liechtenstein), the United Arab Emirates, United Kingdom, Americas, APAC, and EMEA regions[9]. We were not able to determine whether this also applies to voice, video and text communications.

However, Teams is a SaaS solution delivered by Microsoft, which falls under the jurisdiction of the United States government. Encryption keys are owned by Microsoft by default and is therefore technically able to decrypt your data. This may be of concern to clients operating outside the U.S.A.

Security Features and Management

Microsoft Teams is supported separately as a cloud app in Azure Active Directory conditional access policies. Conditional access policies that are set for the Microsoft Teams cloud application apply to Microsoft Teams when a user signs in.

As a component of Microsoft 365, Teams benefits from a comprehensive and granular set of centralized security and compliance management tools well suited to the enterprise, especially if Microsoft AD or Azure are already in use.

Microsoft 365, with all its inter-connected applications is highly sophisticated and complex, however. We feel that without the required skill and appropriate care, the average organization is more likely to suffer a breach due to an accidental leak or misconfiguration than as a result of the technical interception of data by an adversary or Microsoft themselves.

Vulnerability & Exploit History

There is one vulnerability recorded for Microsoft Teams specifically in the NIST National Vulnerability Database in the period from the start of 2019 to the time of writing, but there has been a number recorded for associated products like Skype, Skype for Business and SharePoint.

Year Reported NVD Total Percentage
2019 1 17,308 0.01%
2020 0 7,545 0.00%

On April 28, 2020 Researchers at Cyb0rArk created a proof-of-concept (PoC) attack that involves an inside attacker getting a victim to view a malicious GIF that allows an attacker to take over the victim’s Teams account. They reported two insecure subdomains to Microsoft, which resolved the issue in under a month. Using the bug, an attacker could gain access to an organizations’ Teams accounts by making Teams API calls, which allows one to read and send messages, create groups and add and remove users.

Generally, although there is little data with which to assess this product’s security heritage, it would be fair to argue that Microsoft has robust processes and has developed a strong reputation in this regard.

Sources

Authors

Head of Security Research

Technical thought leader, spokesman and figurehead for Orange Cyberdefense world-wide, leading and managing the OCD Security Research Center – a specialist security research unit. We identify, track, analyze, communicate and act upon significant developments in the security landscape.

Senior Consultant Cybersecurity

Graduated from a French Business School, Quentin is now senior consultant at Orange Cyberdefense operating from Casablanca (Morocco). With nearly 10 years of experience, Quentin has specialized in risk assessment, disaster recovery planning, as well as cybersecurity awareness.

As a specialist in regulatory compliance, Jérôme Mauvais is a security consultant for Orange Cyberdefense. Highly invested in the protection of personal data, Jérôme has also been remarked all along with his career for his great capacities of knowledge transmission.

Lead Security Researcher (MSIS Labs)

Carl has over 20 years’ experience working within IT, covering the whole breadth of the IT infrastructure, with a primary focus and interest on the security-related solutions. This has been followed by a decade working in MSSP’s, the latest of which being at SecureData for over 7 years. Initially as an Escalation Engineer followed by moving into Professional Services then to the Managed Threat Detection team as a Senior Security Analyst before moving into the Labs team as a Lead Security Researcher.


3 Answers 3

With any lens of greater than 300mm focal length on a full frame camera you're probably not going to get results you're happy with shooting handheld. On your 1.6X APS-C camera, the same angles of view are provided by any lens 188mm or longer.

It is true that lenses such as the Sigma and Tamron 150-600mm telephoto zooms are weakest at their longest focal lengths. But they are still pretty good. It is also true that the 300mm f/2.8 series of lenses from Canon are almost breathtakingly sharp.

But without using proper shooting technique, including adequate stabilization, you won't be able to get results that match the capability of those lenses when properly used. You probably won't be able to tell much of a difference at all when hand holding unless your shutter times are close to your camera's fastest shutter speed of 1/4000 second, and even then you'll probably still have detectable blur due to camera movement when pixel peeping images taken with a 300mm prime.

No matter what lens and camera body one is using, 600mm focal length requires excellent shooting technique. Rare is even the seasoned pro that can shoot at 600mm handheld and not get some blur from camera movement. Yes, optical stabilization helps in this regard. But OS/VR/IS/etc. isn't perfect or foolproof at such long focal lengths.

Even on a FF camera, at 600mm much more care must be taken to prevent camera movement from affecting the photographs taken. This is magnified even further when such a lens is used on an APS-C crop body. The narrower angles of view mean that the same amount of camera movement creates more blur than it would with a shorter focal length lens that gives a wider AoV. The narrower AoVs also mean the same amount of subject motion will cross a wider area of the frame (if the subject is at the same distance from the camera). Shorter shutter times can help, but support from a tripod or monopod is almost always required for best results at focal lengths in the 300mm+ 'super telephoto' range. If one is tracking wildlife in motion at very long focal lengths, a gimbal mount that can support the weight of such lenses can be rather expensive, but is also almost indispensable.

Most of the seasoned sports photographers I know (some of whom have been published in major publications such as SI, ESPN The Magazine, the NY Times, etc.) rarely if ever shoot above 200-300mm handheld. You can get good results handheld past 300mm with a FF sensor, but rare is the photographer that can get great results at those focal lengths without more stable support. Monopods are very popular with sports shooters for 300mm+ lenses (on full frame bodies). For notable Wildlife photographers, tripods with gimbal mounts are near universal for anything approaching 600mm.

I added a photo and additional info. I do have a mono/tripod but am unhappy w/it and will be exchanging.

Hummer was approx 35 feet away (maybe a little farther), 15 feet up in tree. Using Program AE, 1/500, Ap 6.3, ISO 6400, at 600mm, handheld (although very shaky!). I only cropped and resized it.

Your results are surprisingly good considered you shot at ISO 6400, 600mm, and f/6.3 (wide open) while hand holding the camera. Just stopping down to f/8 will improve the center and mid-frame resolution performance of that lens. Of course, when you're already at ISO 6400 and 1/500, there's not a lot of room to stop down even two-thirds of one stop.

Here's a comparison between the Sigma at 600mm and the Canon EF 300mm f/2.8L IS II + EF 2X III when both are used on a Canon 7D Mark II (which has a similar sensor to your Rebel T7i/800D) at f/8. The test images were taken from a tripod under laboratory conditions. The 300mm prime is a little better, but nowhere near the price difference between the two setups.

If one compares the Sigma 150-600mm f/5-6.3 C to the much cheaper and older design EF 300mm f/4 + EF 3X III, the Sigma is clearly better. Here's the link to that comparison at The-Digital-Picture. The EF 300mm f/4 is also a non-stabilised lens, so proper stabilization using a tripod or monopod is even more critical in this case.

I'm unsure how hard it would be to move one around while trying to quickly focus on an animal/bird.

The way the best wildlife photographers get their keepers is to accurately predict in advance when and where their quarry will be. That, and a lot of patience. Set up your rig and then wait for the shot to come to you. You may not get it on your first try, or even your first several tries. But eventually you will be in the right place at the right time pointed in the right direction. Increasing the odds of being in the right place and time without spooking your subjects is what is known as field craft. It's a big part of shooting animals and wildlife.

In your case where you are mostly restricted to shooting your back yard from your window or deck, placing feeders in the right places can increase your chances of catching your desired subjects from your more or less fixed shooting positions.

You might also consider a permanent mount for your lens and camera built into a rail on your deck. It might be something as simple as bolting a good tripod head directly to the rail. If the rails are solid they might be more stable than even a very heavy and expensive tripod would be.

The next step would be to get your hands off the camera. I've got a couple of friends who have cameras they set up pointed at their feeders and trigger the camera remotely from inside a window. They either manually prefocus the lens on the feeder or use AF with a specific AF point selected that is pointed at the right spot.


You can set the output resolution of the render in the Properties Editor > Render settings > Dimensions Panel:

For a description of each of these settings, see the Manual:

Resolution:
The Dimensions section has settings for the size of the rendered images. By default the dimensions SizeX and SizeY are 1920×1080 and can be changed by adjusting the X and Y fields. These buttons control the overall size of the image.

Percentage:
Slider to reduce or increase the size of the rendered image relative to the X/Y values above. This is useful for small test renders that have the same proportions as the final image.

Note you can quickly increase or decrease the resolution while keeping the same aspect ratio by setting the Percentage slider below the resolution settings:

Note that to set the Precentage a value greater than 100% you will have to type the value in directly.


Assuming you're scanning 35mm or medium format negatives, and that you want to use the full resolution of your DSLR to digitize your negatives/slides, you can't do it with your setup (D750 + 24–85mm Nikon lens) alone.

Why? You have to think in terms of magnification (also called reproduction ratio). See also:

Your Nikon d750 has a full frame sensor, meaning it's the same size as a 35mm negative frame. For maximum resolution of the digitized negatives, you want them to fill the DSLR's sensor area. So you're looking for a 1:1 reproduction ratio.

Your lens has a maximum reproduction ratio of 0.22x, which means that when your lens is set up at the minimum focus distance (0.38 m / 1.25 ft) at the longest focal length, a 35mm negative/slide will only fill slightly less than a quarter of the width and height of your camera's field of view. Your D750 has 24 megapixels (6016 by 4016 pixels), so after cropping, your digitized images would be (6016 × 0.22) × (4016 × 0.22) = 1324 × 884 pixels = 1.17 megapixels.

For comparison, a flatbed scanner at 1200 DPI would produce images at 1700 × 1134 pixels, or about 1.93 megapixels.

I have digitized a few thousand old slides, film, contact prints, etc., my father inherited from his parents. I used:

Nikon PB-4 bellows with PS-4 slide copying adapter, about $80 on eBay. Here is my PB-4 bellows with PS-4 slide copy adapter attached to the right end:

Nikon Micro-Nikkor Auto 55mm 1:3.5 lens, about $90 used. Here is the setup with the Micro-Nikkor 55mm lens attached to the bellows. Notice that the PS-4 slide copy adapter has its own little bellows that meets lens and attaches to its filter ring threads, to keep stray light out of the light path:

a daylight color-temp incandescent lamp to backlight the slides when scanning (or daylight from a window)

  1. The bellows does not have any electrical contacts, so there is no electrical communication with the lens. This means:
  2. You won't be able to autofocus (which is fine, because once you set focus distance, you won't ever change it).
  3. You won't be able to control the lens aperture from the camera. This is fine if using any Nikon D lens (i.e., with an aperture control ring) or older, such as the Micro-Nikkor 55mm 1:3.5. This means you can't practically use a Nikon G lens such as your 24–85mm ƒ/3.5–4.5G(which does not have an aperture control ring) or the newer electronic aperture "E" lenses. But you wouldn't want to use your zoom lens on the bellows anyways.

Important: the Micro-Nikkor 55mm 1:3.5 (and other Nikon lenses of the same vintage) are non-Ai, so make sure it has been converted to "Ai". Otherwise, you could physically damage your D750.

See also, Can I use a Nikon 50mm f/2 pre-AI on my Nikon D5100? (different specific lens, but same same vintage, same issue). Please see the link in mattdm's accepted answer to that question.

  • Set your camera to full manual exposure, and manual focus (if not using a bellows)
  • Focus using your widest aperture
  • Once you've set focus, tape the focus ring so it won't change
  • Stop down the aperture a bit to the lens's sharpest aperture (ƒ/5.6 for the Micro-Nikkor 55mm 1:3.5, ƒ/5.6–8 for your 24–85 ƒ/3.5–4.5G)

If you have never done any macro photography, or used bellows or film/slide copying setups before, it takes a bit of fiddling to understand how focusing, magnification, and focus distance interact. But for digitizing several hundred slides and negatives at high resolution with your DSLR, this is the recommended setup (bellows, slide holder, cheap old 50–65mm macro lens).

    (Bellows and extension tubes do the same thing: move the lens further away from the camera body to allow for closer focusing / higher magnification.) (photographylife.com) (mu-43.com) (nicovandijk.com)
  • Lots of good ideas here: Let's see your DSLR film scanning setup! (negativelabpro.com)

What's the preferred focal length to use (my 24-85mm lens) for this purpose?

It's not so much about focal length when using a general purpose zoom lens as it is about what type of lens design you should think about using.

People talk about macro lens, is it really necessary if I already have the above zoom lens?

There are a few basic advantages to using a prime macro lens rather than a general purpose zoom lens for digitizing small photographic negatives:

  • Macro lenses are optimized for performing best at close focus distances and most are capable of 1:1 reproduction. Most generic zoom lenses are tuned to perform best at much longer than unity (1:1 reproduction) focus distances, and most of them can't even focus close enough for 1:1 reproduction. When imaging something the same size as your camera's sensor, you want to be able to do 1:1 reproduction so that you can use the full resolution of your camera's sensor instead of using just a small fraction of the center of your camera's sensor.
  • Macro lenses tend to have significantly better flat field correction than generic zoom lenses. What this means is that when the center of the lens is focused optimally on the center of a flat target (such as a flat negative), then the edges will be more in focus than with a lens not as well corrected for field curvature, which will place the sharpest focus distance at the edges and in the corners slightly in front of the flat subject.
  • Macro lenses tend to do less geometric distortion than zoom lenses do, particularly when they are compared to the extremes of the zoom lenses' focal length ranges. Yet to get maximum magnification with most zoom lenses, the longest focal length must be used. Geometric distortion "warps" the subject and makes straight lines appear curved, particularly at the edges and corners of the frame.
  • Prime lenses tend to perform better in terms of overall sharpness than similarly priced, or even more expensive, zoom lenses. Prime lenses are optimized for a single focal length. Zoom lenses must balance optical performance at various focal lengths. If we make a design change that gives a 24-85mm lens better performance at 24mm, that same change often causes worse performance at 85mm with gradually degrading performance at the focal lengths in between.
  • Roger Cicala, founder and lens guru at lensrentals.com, has noted that most wide-to-normal or wide-to-mild telephoto lenses, such as your 24-85mm zoom, tend to perform worse at the longer focal lengths than they do at the shorter end. He calls it "Roger's Law of Wide Zoom Relativity." Yet the maximum magnification of most zoom lenses, which is important for imaging small things such as 35mm negatives, is only available at the longest focal length, where the lens is not as sharp!

As can be seen above, any focal length using a general purpose zoom lens will be a compromise for doing reproduction work of small flat objects, such as 35mm negatives. To get maximum magnification one must use the longest focal length where such zoom lenses tend to not be as sharp. If you use a shorter focal length, you give up magnification. Even if you use extension tubes or bellows to increase magnification with a general purpose zoom lens, you still must deal with field curvature and geometric distortion. Any increase in magnification using extension tubes or bellows also increases the effects of field curvature and geometric distortion, as well as other aberrations such as chromatic aberration, spherical aberration, etc.


1 Answer 1

Selecting, Zooming, and Panning

You pretty much have the right ideas. The Windows User Experience Interaction Guidelines provide standards for this. For example, page 437 specifies:

Single-right-click opens the context menu.

Double-click (left or right) selects and performs the default command.

Single-shift-click (left or right) multi-selects a range that is, it selects everything between the current selection and where the user clicked (in a rectangle, in your case)

Single-ctrl-click (left or right) discretely multi-selects that is, it selects or deselects while maintaining the selection state of anything else.

There are rational responses to ctrl and shift double click too.

Page 438 specifies that, if you have scrollbars, then:

Wheel alone pans vertically.

Tilting the wheel pans horizontally

(I didn’t know about the tilting thing, did you? It doesn’t seem to work with my mouse, even though it’s a relatively new one made by Microsoft. If tilting is not available to a lot of your users, you could try supplementing tilting with Shift-wheel, although you’d need to run a usability test to see which way is left and right –or if users even agree on which way is which).

In one app I use, scroll-wheel zooming zooms in on the point where the mouse is hovering, something I found to be discoverable and very convenient for quickly zeroing in on a specific part of the image. The same app uses shift-pressing of the scroll wheel to pan by dragging, which may make a nice supplement to rolling/tilting the wheel, allowing the user to pan diagonally (the app is 3-D modeler where unmodified pressing and dragging rotates the scene).

Microsoft also specifics that the accelerator keys Ctrl + and Ctrl – zoom in and out, which is probably good for accessibility. In your case, maybe un-modified cursor keys could pan when nothing is selected.

Use of accelerators and the mouse wheel should be considered expert shortcuts, which implies:

There is a more discoverable if less convenient way to do the same actions (e.g., with the scrollbars and menu items).

It’s not necessary for every user to discover and use these features, although the more that do the better.

I don’t believe there is one standard or convention for connecting elements. Your solution isn’t bad, actually. It’s got good discoverability and it’s relatively fast. The main disadvantage I can think of is that it could add too much clutter with all those buttons appearing. What happens if two elements are so close the buttons of one occlude the other? It's also a bit "modey," but with some usability testing, I think you could get it to work acceptably.

One alternative is that instead of a button, a small “hook” (maybe even a visual hook) appears on a selected element alone, and the user drags the hook to another element to connect them. This is perhaps not as discoverable, but it is less cluttering, and it’s analogous to having “handles” to resize elements (which you may also have), so experienced users may still find it quickly. I think I've seen solutions similar to this in certain entity-relations diagramming software, and it's similar to certain types of drawing elements in MS Office (e.g., callouts).

Another option, which is commonly done, is to have a separate pointer tool for connecting. Just as you have a tool for regular selecting, and a tool for zooming (in addition to the mouse wheel), and tools for creating each element, you also have one that, by dragging from one element to another, allows the user to connect elements. This is possibly more discoverable than the option above because the user can see the tool on the tool palette. However, like any use of pointer-tools, it's a bit modey, making it harder to transition back regular selection (or make multiple connections).

As for apps to imitate, look at what your users use now. You also may want to look at MS Visio and MS Project. They're relatively commonly used (and commonly imitated) diagramming apps, so your users might expect your app to work the same way.


Downloading and Installing the Software

First, gather snacks and beverages. Perhaps make a pot of coffee. We’re going to be here a while. Take your Windows based PC, snacks and beverages to a place with good high speed internet – if at home, use an Ethernet cable directly to your PC if you can, it’s faster than WiFi. Then download and install the following software:

    + , any version should be ok, but I chose to install it from the *.ZIP file on Paul Higgins’ site to ensure compatibility with his work in SAT2CHART. Click on the link Sasplanet.zip. Unzip the SasPlanet directory in the zip file to your hard drive, for example to C:SasPlanet. There is no ‘install program’ for SasPlanet: you click on the sasplanet.exe program file to run it. You can create a shortcut to make running it easier, by right clicking on the sasplanet.exe file and selecting ‘create shortcut’ and copying or dragging and dropping the shortcut to your desktop. ™. You MUST use an older version, as the newer versions are not compatible with SAT2CHART. If you have a version other than 7.1.2.2041 (circa 2013) on your PC, uninstall it via ‘settings’ or ‘control panel’ on your computer and then install the correct version from Paul Higgins’ download site. , available from Paul Higgins’ download site (or a newer version if available). Run SAT2CHART, and it may ask you to install additional software just follow the instructions.

All these were current links as of early October 2019, but are likely to change over time.


Fujifilm FinePix 6900Z Review

The only plastic area of the case is this area on the side of the lens barrel which houses several other controls, described below:

Barrel buttons

Manual White Balance / AF in manual focus mode

This button can't really be referred to as "one touch" as you have to select the manual white balance option from the white balance menu, aim the camera at a white subject then press this button, you can't just press it to automatically set a manual balance.

In manual focus mode: This button doubles as a trigger for the auto focus system. You can switch the camera to manual focus mode and then press this button to automatically focus. Useful for locking the focus on a subject for multiple shots.

Information

In record mode displays the current camera settings over the preview display (only while you hold the button). In play mode displays exposure information about currently displayed image.


Obtaining software

Google Earth can be found in many forms. You are more than likely familiar with Google Maps, an application centered on driving directions and location finding, but there is also Google Earth on the web, a Google Earth for for your phone, and Google Earth Pro for desktop (GEP from here on out), a simplistic but fully fledged geospatial software. The lab computers already have this installed, but if you want to do this on your own PC you will need to download and install it.

Setting up GEP

If this is your first time opening GEP, the window will look like so:

Feel free to take the tour to get a head start on the rest of this lab if you&rsquove never used Google Earth before, but we&rsquoll walk though the most important steps below.

One of the first things to do in any software is to look at the options. To find these, go to Tools > Options. Take a second and read though the visualization options in the 3D View tab. Note that the option to change both the Show Lat/Long format and Units of Measurement is in this tab. In the Navigation tab, a useful behavior you may want to turn off is the tilt on zoom option, the &ldquoDo not automatically tilt while zooming&rdquo is the most intuitive zoom behavior and will fix the need to habitually reorient yourself when using GEP to explore. Back on the main application page, if you click View, you should make sure both the Toolbar and Sidebar boxes are checked. There are also several other map options here you might want to explore. Common ones to keep on are the Overview map and Scale Legend.

Before we start exploring the planet, lets take a look at the options and set some of the default behaviors Use the mouse to change your perspective and explore different areas of the globe.

Navigating in GEP

Being able to adeptly navigate around is critical to any geographic software. Nothing is more frustrating that knowing how you want to move around but not being able to do so. Below are the navigation steps, read them and take the time to become proficient with them.

  • To pan in any direction: Left-click and hold. Then, drag the cursor until you see the view you want.
  • To return to the default view (reorient yourself so north is up and the camera angle is pointed straight down) - Click the map and press &ldquor&rdquo.
  • You can zoom in and out to see more or less of a map area. Use the scroll wheel on your mouse or mouse touchpad to zoom in and out.
  • The map controls on the upper right hand side of the map can also be used to pivot, pan, and zoom using just the mouse.
  • Finally, there is a search bar on the toolbar on the left that works just like the search bar on Google Maps.

Move the mouse to the upper-right side of the screen, and a set of controls appear, should you want to use those instead. These controls fade out when not in use and reappear when the mouse rolls over them.

  • The first button, an eye ball surrounded by four arrow marks with ‘N’ marked above the upward arrow, representing the ‘Look around’ function. Grab the N with the mouse (by placing the pointer on N and holding down the left mouse button) and drag the N (that is, slowly rotate it) around the ring (this is commonly called “grab and drag”). You see the view change (north will still be the direction in which the N is pointed). Clicking on the N returns the imagery so that the north direction is facing the top of the screen.
  • The second button, a palm shaped symbol in the center surrounded by four arrow marks, representing the ‘Move function. By selecting one of the directional arrows and clicking it with the mouse, you can tilt your view around the terrain as if you were standing still and looking about. You can also grab the control and move it (by holding down the left button on your mouse) to simulate looking around in various directions. Recall from above that you can reset your view with the &ldquor&rdquo key.
  • You&rsquoll find the Street View peg man button below that. This icon appears when Google Street View imagery is available to see on the ground. To use Street View, you would grab the icon with the mouse and drag it to a street that’s visible in the view to enter the Street View mode. This control is visible only if there are streets in the view through which you can enter Street View mode
  • Below that, there is a zoom slider with ‘plus’ marked at the top and ‘minus’ marked at the bottom. The zoom slider is marked at the center of the slide.

In the search box, type in University of Kansas. As GEP rotates zooms in, look to the Layers box. Make sure that both Photos, 3D Buildings, and Terrain are selected. This enables linking of locations on the ground to photos that users have taken. The locations that have linked photos have small blue and brown circles over the imagery. Click on the photo symbols on the imagery to see some photos.

See if you can locate the building you are currently in by panning and zooming around the campus. If you got lost or aren&rsquot on campus but are playing along, type in Lindley hall, KU into the search bar. Grab the Street View icon from the controls and drag it to the street right in front of the building. You’ll see large areas of the campus pathways and roads turn blue (which indicates that Street View imagery is available for this street). Release the icon on the street, and the view shifts from an aerial view to imagery that looks like you’re actually standing in that spot. Use a combination of the Street View and imagery to answer question 1:

  1. From the GEP Layers panel, make sure Roads is checked. You’ll see major roads (interstates, state highways) identifiable as their labels appear, and local roads will also be identifiable when you zoom in close. We’re going to plan a lunch trip to the greatest restaurant in Lawrence, Thai Diner. In the Search box, click on the Get Directions option. In the A option (this is where you’re traveling from), type in Lindley Hall. In the B option (this is where you’re traveling to), type in Thai Diner. Finally, click the Get Directions button. GEP zooms out to show you the path it calculated for driving distance between the two points, and the Search box fills with directions featuring stops and turns along the way.

The capabilities to take a bunch of letters and numbers and turn them into a mapped location and to calculate the shortest driving distance between points are some of the core functions of GIS, and we will develop these later in the course. For now, you can click the X at the bottom of the Search box to clear the directions and remove the route

Exploring landscapes in GEP

Kansas has some truly gorgeous landscapes, but it is mathematically flatter than a pancake, so let&rsquos go explore a slightly more topographically diverse landscape. The closest National Park to Lawrence, the Badlands national park, is just to the northwest.

  1. To see the boundaries of Badlands National Park, go to the Layers box and expand the option for More (click on the triangle to the left of the name). In the options that appear under the expanded heading, put a checkmark in the Parks/Recreation Areas option.
  2. Pan and Zoom out until you see the northernmost boundary of Badlands National Park highlighted in green. If you get lost remember you can use the search function. Once the park is centered in your view new icons for the locations of Visitors Centers and other features should appear. Pan over to the eastern edge of the park, and you see a large Question Mark icon indicating a park entrance as well as a green arrow indicating an overlook.

Make sure that the option for Terrain in the Layers box is turned on. Zoom into the point representing the overlook. At the bottom of the main map you&rsquoll see numbers representing the latitude and longitude of the point, as well as the real-world elevation of that spot.

The imagery in GEP is placed on top of a model of Earth’s terrain. To get a better view of this extra dimension, use the Zoom Slider to tilt the view down (remember you can also hold down the Ctrl key and move the mouse to change your perspective) so that you can look around as if you were standing at the overlook point (in a perspective view of the planet). Once you’ve tilted all the way down, use the Look controls to examine the landscape. From here, use the Move controls to fly over the Badlands from this overlook point. Once you feel like you have a decent feeling of what the Badlands looks like, answer Question 5.

This ability to model the peaks and valleys of the landscape with aerial imagery “draped” or “stretched” over the terrain for a more realistic appearance is often used with many aspects of geospatial technology, and we&rsquoll explore some of these analyses in more depth later in the semester.

Using GEP to Save Imagery

It’s time to continue to the next leg of our journey by heading to Mount Rushmore. Carved out of the side of a mountain in the Black Hills, Mount Rushmore National Memorial features the faces of presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln. For more information about Mount Rushmore.

  1. In GEP’s Search box, type &ldquoMount Rushmore&rdquo. GEP zooms around to an overhead view of the monument. Like the Badlands, Mount Rushmore is overseen by the National Park Service. Zoom out a little bit and you’ll see the extent of the memorial’s boundaries (still outlined in green). Let&rsquos save an image of what’s being shown in the view. Although we could use the snip tool, GEP can take a “snapshot” and save it as a JPEG (.jpg) file. Position the view to see the full outlined extent of Mount Rushmore, select the File > Save > Save Image. You’ll see the two most common map elements appear, a box with a legend and a title box with Untitled Map in it. Click on that to give your image a name. If your text gets too long, you can enter a new line by pressing Shift-Enter. Once done, you&rsquoll see at the top of the map window there are options including map options, image resolution, and he save button. Once you are happy with your setting hit the save button and save the image to your PC.
  2. Minimize GEP go to the location on your computer where you saved the image and open it (using a simple image viewer like Microsoft OfficePhotos).

Even though the saved image doesn’t have any spatial reference data, we&rsquoll cover how to add that back in later in the class. For now, you can turn off the Parks/Recreation layer.

Using GEP to Make Placemarks and Measurements

While you’re examining Mount Rushmore, you can set up some points of reference to which you can return. GEP allows you to create points of reference as placemarks. Let&rsquos set up three points on the map: the top of the mountain, the amphitheater, and the parking area.

  1. From the GEP toolbar, select the Add Placemark button (1)
  2. A yellow pushpin (labeled “Untitled Placemark”) appears on the screen. Using your mouse, click on the Pushpin and drag it to the rear of the amphitheater so that the pin of the placemark is where the path meets the amphitheater (2)
  3. In the Placemark dialog box, type &ldquoMount Rushmore Amphitheater&rdquo (3)
  4. Click the Placemark icon button next to where you typed the name, you can select an icon other than the yellow pushpin. Choose something more distinctive (4) When finished, click OK to close the dialog box.

  1. Put a second placemark at the top of the mountain by repeating this process. Name this new placemark &ldquoTop of the Memorial&rdquo. When done, position the two as tightly within the view as possible.
  2. Click on the Ruler tool on the toolbar. In the Ruler dialog box that appears, select Feet from the Map Length pull-down menu Use the options on the Line tab, which allow you compute the distance between two points. If you wanted to measure multiple points, you could do so from the Path tab. Using this tool, measure the distance between your two placemarks to answer the question below:

When you’re done, click on Clear in the Ruler dialog box to remove the drawn line from the screen and then close the Ruler dialog box. These abilities to create points of reference (as well as lines and area shapes) and then compute the distances between them might seem trivial, but these process level functions form the heart almost every GIS tool.

  1. Finally, let&rsquos use the Tilt functions of GEP to get a perspective view on Mount Rushmore (as we did in the Badlands). Make sure that the option for Terrain in the Layers box is turned on and 3D Buildings option is turned off. Note that although you can see the height and dimensions of the mountain, the famous four presidents’ faces can’t been seen.

Now turn 3D Buildings on, can you see them now?

Exploring landscapes in GEP

Notice that next to the elevation value at the bottom of the GEP screen, there’s a set of coordinates for lat (latitude) and long (longitude). Move the mouse around the screen, and you see the coordinates change to reflect the latitude and longitude of whatever the mouse’s current location is.

You can also reference specific locations on Earth’s surface by their coordinates instead of by name. In the Search box, type the following coordinates: 43.836584, –103.623403. GEP rotates and zooms to this new location. Turn on Photos to obtain more information on what you’ve just flown to. You can also turn on the 3D Buildings layer (if necessary, again using the legacy 3D Buildings option, as you did with the Corn Palace and Mount Rushmore) to look at the location with a 3D version of it there.

  1. Answer Questions 10 and 11, and then turn off the Photos (and the 3D Buildings option) when you’re done.

Other Features of Google Earth Pro

Google Earth Pro changes with new updates and features, but some of the more novel features include Google Mars, Google Sky, and Flight Simulator.

Google Mars

From the View pull-down menu, select Explore > Mars. The view shifts to the familiar-looking globe, but this time covered with imagery (from NASA and the USGS) from the surface of Mars. The usual controls work the same way as they do with GEP, and there’s a lot of Martian territory to be explored. When you’re ready to return to GEP you use the same View > Explore menus and then select Earth.

Google Sky

From the View pull-down menu, select Explore > Sky. GEP’s view changes: Instead of looking down on Earth, you’re looking up to the stars, and instead of seeing remotely sensed aerial or satellite imagery, you’re looking at space telescope (including the Hubble) imagery. There’s plenty of imagery to be explored in this new mode. When you’re ready to return to GEP you use the same View > Explore menus and then select Earth.

Flight Simulator

From the Tools pull-down menu, select Enter Flight Simulator. A new dialog box appears, asking if you want to pilot an F-16 fighter jet or an SR-22 propeller airplane. Select whichever plane you want to fly GEP switches to the view as seen out the cockpit of your chosen plane, and you can fly across South Dakota (and the rest of GEP). Try not to crash (although you can easily reset if you do).


Watch the video: Openlayers 6 Tutorial #4 - View in Openlayers