How to Efficiently Extract Values from a Raster at Many Points

Today I had a conversation with myself on the ESRI ArcGIS Desktop - ArcObjects General forum.

Forum Thread

In the end, I have two conclusions:

1) Using IIdentify.Identify on a RasterLayer is a very inefficient way of extracting the raster value at an X, Y point. Better to use IRaster.Read... but make sure you pay attention to your coordinate units.

IIdentify.Identify interprets incoming x, y values as data units (I have no projection on the fly going on in my data frame)

IRaster.Read interprets incoming x, y values as pixel counts from the origin of the raster data.

2) Sometimes you can solve problems by talking to yourself.

Talk to you soon,

-Cory

www.eicher-gis.com