Chapter 6 | Importing Google Imagery

Google Earth Import Tool

Virtual Tutor: Go to help > google maps > insert to learn more about using the Google Maps import tool.

With Virtual CRASH for Public Safety, you can import Google Earth aerial images directly from the Virtual CRASH user interface. It is required for users to obtain the needed API key before using the Google Earth feature.

Google API Key

To access the Google Earth import tool, simply left-click on Create > Google > Google Maps (see below).

If you do not already have a Google API key set up, you will see the Google Settings prompt appear (see below). 

In order to use the Google Earth tool, you will need an application programming interface key (“API key”) from Google. If you do not already have a Google API key set up, please carefully follow the steps in our Blog post:

http://www.vcrashusa.com/blog/2018/8/7/steps-to-generate-your-google-api-key

Google Maps Interface

Using the Google Earth interface, enter the address of the location you wish to download.

Using the “Map Type” dropdown menu, one can select from roadmap, satellite, hybrid (satellite with road labels), or terrain map image options.

By default, Virtual CRASH for Public Safety will download the image shown within the display window; however, using the “Region” option allows one to specify the specific region of interest using a box selection tool. Simply left-click on “Region” and then left-click on the box control grips to adjust the selection area (Virtual Tutor: Go to help > google maps > region). Virtual CRASH for Public Safety will partition the selected area into a grid and download and mosaic the needed images from Google using the highest quality images possible. You will likely need experiment to understand the tradeoff between image resolution quality and selection area size given hardware limitations on displaying large amounts of high-resolution images simultaneously.

Below we see the difference in image quality for single image import versus using the “Region” selection tool for a large scene. Note, for smaller scene sizes, the differences between negligible.

When the “Region” selection tool is used, images are downloaded and stored in a group object (see Chapter 2 to learn about groups). You can browse through the group object by opening the folder icon and left-clicking the “+” symbol.

It is recommended to freeze the group object after importing to prevent accidentally selecting and moving individual tiles or place the group. For single image importing, it is also recommended to freeze the image object. Another approach is to place the imagery data into a layer and freeze the layer. In the example below, the layer within which the imagery data is stored is frozen.

 

Note: It is well known that aerial imagery from Google Earth generally provides reasonably accurate representations of various scenes, it is highly recommended that the accuracy of Google Earth aerial imagery products be verified using direct scene measurements. We do not, nor cannot, guarantee the accuracy of Google Maps products, as these products are based on Google’s proprietary data and methods. To learn more, visit: https://enterprise.google.com/maps/. We remind all users of Virtual CRASH brand products that in using Google Maps products, you are subject to Google Map API’s terms of service, which can be found here: https://developers.google.com/maps/terms.

Tags: Google Maps, Google Earth, Google Images, Google Imagery, aerial images, maps, orthos.

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