Join Adam Wilbert for an in-depth discussion in this video Working with air photos, part of ArcGIS Essential Training.
- Aerial photography can come from an increasing number of satellite constellations, captured from high or low-flying airplanes, or even produced by amateur cartographers from small balloons or kites. Probably the most well-known satellite platform is the USGS Landsat satellites. The imagery that Landsat 8 captures is collected in 11 distinct bands of information called scenes. An individual Landsat 8 scene can regularly include more than 2 gigabytes of data. So they're pretty hefty files. I've included four of the 11 scenes here inside of the Landsat folder inside Chapter 9.
These are indicated by Band 2, Band 3, Band 4 and Band 5. Now if I click on these and choose the Preview tab here inside of out catalog, you'll notice that these are all grayscale images. These represent just a single band of data. Let's see how we can take these bands and combine them into color composite images. To do that, I'm going to launch Art Toolbox here. Then I'm going to go into Data Management Tools, Raster and then Raster Processing. I'm looking for the tool here called "Composite Bands." Let's go ahead and double-click on it to run it. Now we just need to load in out input Rasters.
But the order that we place them in here is important. In the Landsat satellite, Band 4 is our red data, Band 3 is our green data and Band 2 is our blue data. We need to load the Composite Bands dialogue box in that order. So I'm going to grab Band 4 here, drag and drop it up into Import Rasters. Then I'm going to take Band 3 and drop it below. Then I'm going to take Band 2 and drop it below those. Now in the output Raster section, we're going to tell it where to put it. It's going to go into the Chapter 9 folder inside of Landsat, and I'm just going to click and highlight to the end so I can see the name.
I'm going to change the name after the last backslash to colorcomposite.tif. Let's go ahead and say "OK" to run the tool. After a brief processing time, the color composite TIF is created. I can click on it here and in the preview I can see that it's a color composite of the image around Seattle. I can see I've got brown mountains over here, I've got green trees over here, and I've got the urban areas are represented in gray. If I wanted to, I could zoom in and see even more detail. So that how we can create a natural color composite image. Now let's see how we can create a color infrared image using Band 5. Once again, I'm going to go down to Composite Bands and double-click to run the tool.
This time, instead of Bands 4, 3 and 2, we're going to used Bands 5, 4 and 3. I'll click on 5 and drag it in. I'll click on 4 and drag it in. And then we'll click on 3 and drag it in. This time I'm going to go ahead and rename this file to the end, and I'm going to call it "Color Infrared." I'm going to go ahead and type in the name, and we're going to call it colorinfrared.tif. Let's go ahead and say "OK," and again, it will process the image. I can keep track of it by looking down here to see the status message down at the bottom. And if I want to, I could see the results by clicking on that and seeing the results section from my current session.
Let's go ahead and close the Results window, and wait for it to finish processing. When it gets done, the new Raster image is added to my Landsat folder. So, here's Color Infrared. I can click on it to see what that looks like. Infrared images are great for studying the health of vegetation. Healthy vegetation shows up bright pink in these types of images. If I wanted to, I could go ahead and zoom out to the full extent to see the entire scene as a color infrared image. So Landsat satellite imagery is an extremely valuable resource when doing vegetation or landscape analysis over large areas. By combining the available data bands together in different ways, a GIS analyst is able to enhance features that are important to understanding the environment.
- Getting to know the ArcMap interface
- Geocoding addresses
- Measuring distances
- Adding and importing data
- Labeling and adding graphs
- Editing layer properties
- Seeing multiple views
- Making selections
- Exploring geospatial data with ArcCatalog
- Working with vector and raster data
- Styling the map
- Adding your own data
- Using the ModelBuilder
- Adding a legend and annotations