ArcMap Tool: Composite Raster and Divergence Tool

Files

-FoxCompositeRasterAndDivergenceTool_10_5.esriAddInn this is the compiled ArcGIS AddIn file that can be added ArcGIS 10.5

Overview

The Composite Raster and Divergence Tool is an ArcGIS ArcMap add-in developed at UMESC. When using this tool, a user can:

1. create a date prioritized composite raster from a collection of raster layers
2. create a lookup raster for the composite raster that identifies which input layers were used to create the composite raster
3. create a divergence raster where pixel values represent the divergence from a user specified value

Installation:

To install this tool:

1. within a session of ArcMap 10.5, open the Add-in Manager dialog
2. click the Options tab
3. add the folder location to where you locally download the file FoxCompositeRasterAndDivergenceTool.addin
4. click the Customize button
5. click the Commands tab of the Customize dialog
6. Find the Fox Tools category
7. Drag the Composite Divergent Raster command button to an empty space within ArcMap Save your ArcMap session to save the user interface changes to the Normal template

Input dialog:

Composite Raster and Divergence Tool input dialog

Example analyses:

All the example analyses will have the following parameter values: Date = 1/2/2017 Divergence Value = 4 (degree Celsius) Data Folder = xxxx

MODIS Sea Surface temperature (SST) will be used to demonstrate how the tool handles input rasters and creates the divergence output. The use of SST data is purely for demonstration purposes only. We will run the tool twice, the first time we will set Composite Raster = true and +/- Days = 32, then we will rerun the tool with Composite Raster = false, and compare the outputs. For all Composite Raster and Divergence Tool analyses, valid raster inputs must contain a date within their name. These dates must follow the mm_dd_yyyy or mm-dd-yyyy format. The data folder specified above contains 8-day MODIS Sea Surface Temperature (SST) scenes from September, 2016 to May, 2017. Important Note: the Composite Raster and Divergence Tool was designed to be an exploratory tool. Therefore, outputs from this tool are created as temporary datasets that will be deleted when your ArcMap session closes. To save an output: right click the data layer in ArcMap, click the Data item from the popup menu, and select the Make Permanent option.

Example: where Composite Raster = True When Composite Raster = True and +/- Days = 32, the tool will consider any raster layer with a date that is plus or minus 32 days of the user specified input date. The Composite Raster and Divergence Tool merges these raster data together to create a composite raster, prioritizing data collected nearest the user specified date. By doing so, areas within the MODIS satellite data that are obscured by cloud cover are iteratively filled in with the most temporally relevant data. The tool stops filling in data gaps when the +/- Days limit is reached. Resulting in the creation of two new raster datasets, the Composite Raster, and the Composite Days Diff raster. The Composite Raster is the merged dataset, and the Composite Days Diff raster maps the difference in days of the user specified date and the dates of the input rasters used to create the Composite Raster.

Composite Raster output created by the Composite Raster and Divergence Tool, where the Composite Raster option is set to true.

Composite Days Diff output 

The tool then uses the Composite Raster to create a Composite Divergence raster layer. This layer shows how values diverge from the user specified Divergence Value. In this example we are focusing on water temperatures = 4 degrees Celsius. The title of Composite Divergence layer identifies the Divergence Value, the minimum absolute difference in days from the input rasters dates and the name of the input raster dataset that most closely matches the user specified date.

Composite Divergence output created by the Composite Raster and Divergence Tool.

The user specified divergence value was 4 degrees Celsius, this output shows how the composite raster diverges from that value. Note that many of the areas that are at or near the target value of 4 degrees Celsius are from No Data areas that the tool filled in with raster input data.
Example: where Composite Raster = False When the Composite Raster checkbox is not checked, the tool will identify the raster dataset with the date closest to the user specified input date, add it to the ArcMap project and label it Single Value. The tool will also create a raster divergence output and label it Single Raster Divergence.

Single Raster output created by the Composite Raster and Divergence Tool,

where the Composite Raster option is set to false. Note the areas of No Data when compared to the Composite Raster 

Single Raster Divergence output created by the Composite Raster and Divergence Tool.

The user specified divergence value was 4 degrees Celsius, this output shows how the raster diverges from that value.