ArcGIS Desktop – How to Resolve Projected Raster Data with Inconsistent Extent but Not ShapeFile

arcgis-desktopcoordinate systemextentshomolosine

I want to calculate the average value of a raster file within each polygon boundary of my shapefile. Because I want to preserve area I wish to use the Goode Homolosine (Land) projection. The original shapefile has a geographic coordinate system WGS1984, and the original raster file is also in WGS1984.

I used the Project tool to project the shapefile to the Goode Homolosine (Land) projection, and the Project Raster tool for the raster file, also choosing Goode Homolosine (Land) as the projected coordinate system.

It is my understanding that because both of the original files have a defined coordinate system, i.e., WGS1984, I should not be using the Define Projection tool.

Problem: When I open the newly projected raster file in ArcMap, I receive the following error message:

Warning, inconsistent extent!

One or more of the added layers has an extent that is not consistent with the associated spatial reference information.

Re-projecting that data in such a layer may lead to unexpected behaviour

Two things to note:

  1. I do not receive this error message when I add the newly projected shapefile;
  2. This error message occurs even when I add the newly projected raster file to an empty data frame (which, if I understand correctly, should automatically determine the coordinate system for me).

I have just spent a considerable amount of time reading on how to re-project data and cannot see any problem in what I am doing.

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Raster data: http://www.earth.columbia.edu/people/gmccord/sitefiles/file/malaria_ecology.zip
Shapefile is not publicly available, but metadata states GCS_WGS_1984

Best Answer

There is a bug in the Project Raster Tool. The output raster from the Project Raster tool is a little too big on the eastern edge, and on the southern edge (bottom of the easternmost gore/lobe). So the data extent doesn't quite match what the extent of a Goode's Homolosine projection is, and triggers the "not consistent extent" warning.

A workaround is to reproject the original raster in ArcMap and then export it using the data frame's coordinate system.

  1. Add the original raster to ArcMap
  2. Set the data frame's coordinate system to projected coordinate systems, world, Goode's Homolosine (Land).
  3. Right-click the layer's name in the table of contents and select Data, Export Data.
  4. In the dialog, use the raster's original extent, and the data frame's spatial reference. Update the output path and raster name. In my test case I left everything else the same.

Note: My first "answer" below was completely wrong, and I hadn't actually tried the OP's workflow when I wrote it. I think I see what happened, but I'm surprised that the Project Raster tool worked.

When I downloaded the raster, it has no defined coordinate system. I think the Project Raster tool failed silently and the output raster is still in WGS 1984 coordinates but has the Goode Homolosine defined. Go back to the original, use its property page in ArcCatalog or the Define Projection tool and set it to 4326 / GCS WGS 1984. Now use the Project Raster tool to convert it to Goode Homolosine.

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