Category: Tips and Tricks

Tutorial: Data Overlay with QGIS

It is easy to overlay your own points of interest over Vexcel Imagery in common GIS tools like the Esri family of applications and QGIS. This is especially useful in Catastrophe response situations where insurers want to overlay their policy information over the graysky imagery.

In this tutorial, we’ll look at how to add Vexcel layers into QGIS, import your points of interest as an overlay, and do some simple analysis.

Before you get started, you should have an account providing data access to the Vexcel platform. If your organization has a license to our imagery and you need an account, email your request to support@geointel.org

Step 1: Install QGIS if you don’t already have it. It is a free download for all platforms. Install it from here.

Step 2: Start QGIS and add the OpenStreetMap Basemap Layer. I start every project by adding this layer, providing a high quality backdrop for Vexcel Imagery. In the left rail menu, open the ‘XYZ Tiles’ section and double-click OpenStreetMap. the layer will be added to the map canvas and show up in the layer list below.

Step 3: Add the Vexcel WMTS Connection. Right Click on the WMS/WMTS section in the left menu and choose ‘New Connection…’. Give your connection a name like ‘VexcelPlatformWMTS’ and specify the URL as ‘https://api.gic.org/wmts?request=GetCapabilities’

In the Authentication section, specify your Username and Password for the Vexcel Platform. When your screen looks something like this, hit the OK button to initialize the connection.

Step 4. Add a Vexcel Layer to the map. Once you’ve added the connection in step 3, all of the Vexcel Layers will appear below it. Double click any of them to expand it, then double-click on the ‘PNG’ option to add the layer to the map. We’re going to add the ‘graysky’ layer to pull in imagery from the California Wildfires. Hurricane Laura Imagery will appear in this layer as well as it becomes available.

Once the layer is added, zoom in the map north of San Francisco and you will see the imagery appear.

Step 5: Import your Points of Interest. In QGIS you can import data as overlay layers from a variety of formats. We’re going to import a simple comma separated file (CSV) exported out of Excel. Your data should have columns for Latitude and Longitude, along with any other fields of data you would like to bring along. Here is a simple CSV file that we are going to import:

latitude, longitude, name
38.4711, -122.1070, Vacaville
38.615336, -122.880297, Healdsburg
38.406523, -122.008205, Vacaville 2

In QGIS, Choose the Layer => Add Layer => Add Delimited Text Layer… Menu

Browse to select your file. QGIS will analyze it and try to find the latitude and longitude fields. Be sure the X field and Y field values match your data file. Once your screen looks something like this, hit the Add button to add your layer to the map.

You did it! Your points should appear on the map, something like this image shows.

Here are a couple of QGIS tips. Use the ‘Identify Features’ button on the tool bar to click on one of your points to see the details as shown here.

Aerial Imagery viewer quickstart tutorial

The Vexcel Web app is a powerful tool for accessing our entire imagery library. Although it is fairly intuitive to get started with, this post will provide a step-by-step quick-start for those of you wanting to access our disaster response imagery for the California fires. Additionally I’ll show the steps needed to turn on the ‘dual view’ feature enabling easy side by side comparison for before and after looks at a property.

Before you get started, make sure you have an account to access our web app at https://app.gic.org/ Accounts are free to first responders and state and local government agencies needing access. Members of the GIC also have unlimited site license to access the app. If you need an account email us at support@gic.org.

One more thing to understand as you go through this tutorial – ‘Graysky’ refers to our disaster response imagery, typically captured after a hurricane, tornado, wildfire, etc… while ‘Bluesky’ refers to our high quality aerial imagery captured with good weather conditions and sun angle. Our focus in this tutorial is to inspect a property damaged in the wildfires using our Graysky imagery, but then to use the Bluesky imagery to see what it was like before the fires.

OK, with that housekeeping out of the way, lets get to it. We’ll use this address in the steps below: 3579 Gates Canyon Rd, Vacaville, CA 

Step 1: Sign in at https://app.gic.org/

Step 2: The Search tool is at the top of the toolbar on the left side of the app. Enter the address and hit return. Like any other web map app that you have used, you can zoom with your mouse wheel, the + and – keys on your keyboard, or the zoom buttons in the lower right of the screen. If you have a touch screen (how do you work without one?!?) you can pinch to zoom as well. Go ahead and zoom in for a nice tight view of the property as shown below.

Step 3: The second icon down on the toolbar is the layer control. In a mapping app, typically the top most layer in the list is the one you are seeing on the map canvas. Since we want to see the wildfire imagery, uncheck all of the layers except for the Graysky layers. The date the image was captured is always shown in the lower right portion of the screen. You can also right-click anywhere on the map and choose ‘Get Info’ to display the address, coordinate and capture date. FOr our example address, we can see the image was captured on August 22nd.

Step 4: The Dual view icon is at the bottom of the toolbar on the left. Click it to split your screen in half providing two synchronized views. As you navigate on one side of the map, the other side will be kept in synch. Initially you will have the SAME layer visible on each side of the interface, but you can use the layer control on either side to change that. This feature is most often used to have Graysky on one side with blue sky on the other as shown here.

I hope you find this quick tutorial helpful in getting started viewing our disaster response imagery. The features shown here just scratch the surface of what you can do in our web application. If you want to learn more, I suggest checking out some of the videos in our help center or the Vexcel Viewer User Guide.