I have a multi-point shapefile representing earthquake hypocenters (containing depth values) and I have a DEM raster representing an underground surface (the top of the PreCambrian basement). I want to select only the points whose depth values are greater than the elevations in the DEM. Is there a way to do this?
To start to this (quoted from source):
...There's a tool at Spatial Analyst Tools\Extraction\Extract Multi Values to Points and Extract Values to Points. Extract Multi Values to Points is better because it lets you rename the z field name that you are extracting your values to—Extract Values to Points doesn't let you do this. I have trouble doing this in ArcMap (the tool crashes), but it works fine in ArcCatalog.
Once you have the dem data in the point file attribute tables, create a new field named like Elev_Diff and use the field calculator to calcuate the values. Then you can use a def query or select by attributes to only select the negative values.