Multi-spectral Images analyzed in ArcGis pro.

Opening Window of ArcGis Pro

Introduction:

                       When taking imagery via unmanned aerial vehicles there are many applications. Depending on the type of video captured you may need special software to utilize the data collected. In the following lab multi-spectral imagery of a field before and after a controlled burn of the area is manipulated to better display data for use in analyzing the burn.

Method:

When opening imagery in ArcGis pro, the default image will be one with normal color bands.

Default field image pre-burn

Default field image post-burn

After an image is opened in the main screen you can open up the symbology window as shown on the right.

From here you can change what color band is used in place of Red, green and Blue.

When you do so, certain colors will change in the image, making a sort of mock up version of infrared, or other types of light lengths not typically visible to the naked eye.

By doing so certain data can be gathered more easily than with a default wavelength setup.

Post Burn image with bands 5 3 2

Post Burn image with bands 4 3 2

As one can see the colors are very different in the images than you would normally view with the naked eye.

Another option is to use NDVI images, which function as a sort of color gradient mode, where the user can chose a color scheme to display contrasting changes.

NDVI image pre-burn

NDVI image post burn

NDVI Symbology
Window

Like with the Symbology window to change bands, there is a symbology window for NDVI images that allows the user to change the color scheme of the image, either showing continuous data or discrete data.

If the user chooses a gradient color scheme, the image will show continuous data.

If the user chooses a non-gradient color scheme, the image will show discrete data.

However, some images will not work with a discrete data scheme, such as the ones used in this lab, this is illustrated below;

NDVI Color Gradient

NDVI Color non-gradient

Discussion:

Using software such as ArcGis pro has many applications with multi-spectral imagery. In the images above with changed bands, or the NDVI gradient images, it is much easier to see which areas of the field lack vegetation post burn. Areas that you wouldn't normally notice, such as the footpaths become more obvious to the viewer when they know what to look for. To an uninformed viewer it may be a little confusing at first with the different colors, but after an explanation it becomes clear how this is an effective tool to gather data.

Conclusion:

Knowing which type of imagery one should use when handling data is important. Obliviously some of the images used in this lab, such as the non-gradient ones, have no real application for the purpose of the experiment. However, when an individual knows how to properly use software such as ArcGis pro to edit imagery to find data as they see fit they will be a much more effective worker.