Tag: Image Analysis window
I came across this recent paper that looked at how agricultural practices have changed in the Loess Hills region in China due to a policy known as Green for Grains that encourages replacing agriculture with trees and natural grasslands to … Continue reading
Continuing with the recent mini-series on using the Image Analysis Window with spectral indices, today I’m going to show you a quick workflow for detecting change. You could take something like NDVI from two points in time, subtract the earlier … Continue reading
The NDVI (Normalized Difference Vegetation Index) tool in the Image Analysis Window calculates how vigorous the vegetation is in an area. But it’s not the only index available, although it may be the most widely used.
When you have the Table of Contents open along with the Image Analysis Window, you’ll notice that the order is the same in both. Move an image up in the TOC and it will move up in the Image Analysis … Continue reading
The Processing pane on the Image Analysis window contains various tools that can instantaneously process your data on-the-fly. However not all of the button are active all of the time. This is because each tool is dependent on the layers … Continue reading
The Interactive Histogram Stretch tool can be found on the Image Analysis window. It allows you to set the minimum and maximum histogram values for each band. By adjusting the tails of the histograms you can adjust how the curve … Continue reading
Have you ever played around with the Brightness, Contrast, Transparency, and Gamma sliders in the Image Analysis window? Now have you used the slider and then wanted to return back to zero? Sure you can try to move the slider … Continue reading
There are several ways to persist your Image Analysis results.
Imagery Analysts frequently have to measure features and determine their height. At ArcGIS 10.1, the Image Analysis window provides tools that give you the ability to take measurements of building heights directly from imagery. The process of making such measurements on imagery is referred to as mensuration. Mensuration tools apply geometric rules to find the length of lines, surface areas, or volumes using information obtained from lines and angles. Mensuration can include measuring the height and absolute location of features. Any georeferenced raster dataset can provide distance, area, point, and centroid location. Height measurements can be obtained when the sensor model is known. Sun angle information is required for measurements using shadows, while 3D measurements require a DEM.
This image shows how you could use the Base to Shadow tool to find the height of a building. The height is calculated by selecting a point at the base of the building and the corresponding point at the top of the shadow. For more information on the Mensuration tools and how to use them, see the ArcGIS Online Help.
Contributed by Natalie Campos.
Last week’s Imagery Blog was about combining all your imagery bands into one raster. Putting all your bands into one raster means it is easier to manage and use. This week’s blog will discuss the ways to composite your bands together.
There are a two main ways to achieve the composite bands task:
- Composite Bands button on the Image Analysis window
- Composite Bands Geoprocessing tool