Creating Latitude Grid from DEM

Question

I am trying to evaluate an equation in the raster calculator and I need latitude values. I have the DEM for the region and am wondering if it is possible to create a latitude raster based on the DEM?

Thanks a lot!

Answer 1

Unproject the DEM to determine the geographic region it covers.

Create the latitude coordinate grid for this region. (In Arc* products prior to version 10, this is done with "$$YMap": http://forums.esri.com/Thread.asp?c=93&f=1740&t=182407.)

Projecting this grid produces the latitude raster. For the projection, use some form of interpolation for the resampling (bilinear should be good enough in most cases), not nearest-neighbor.

Answer 2

whuber's method is simpler, but this should also work if you have Spatial Analyst and ArcGIS:

1. Spatial Analyst Tools > Extractions > Sample, to create a points layer for each cell
2. Add X and Y fields to the points layers and calculate the X and Y values using "calculate geometry"
3. Use Conversion Tools > To Raster > Points to Raster to create a new grid for each value.