Intersecting raster elevation data with shapefiles (or something equivalent)?

Question

Hello,
I am trying to isolate contaminant source areas that, for our purposes, are defined by being within 30m of a stream/river, C or D soil hydrologic groups, and negative curvature (concave topography). There are no complications intersecting the buffered streams and the soil unit polygons corresponding to the appropriate hydrologic groups, but how do I then isolate the concave areas identified by using the curvature tool within that intersection?

I'm working with a 30m (1 arcsecond) SRTM DEM that I reprojected to UTM, resampled to 10 acre pixels, then applied the curvature tool to. I cannot seem to build an attribute table for the curvature output file (pixel depth seems to change so it thinks there are multiple bands???) or convert it to a shapefile so that it might be compatible with the soil and stream shapefiles.

Am I overlooking some secret tool or simply taking the wrong approach to this issue? I'm using Desktop 9.3.1 with an ArcInfo license.

I would greatly appreciate any suggestions/help. Thanks!
-Alexis

SteveLynch · Answer

Alexis

I'm glad to hear that you've solved your problem.

A raster attribute table can only be created for integer rasters and Curvature produces a floating point raster and that is why you could not build a table.

-Steve

AlexisCoplin · Answer

Got it! My friend suggested I use the Raster Calculator (Spatial Analyst toolbar) which worked beautifully. This allowed me to assign a grid code value of 1 to all pixel values <= 0 (flat or concave). From there, I was able to convert the calculator output to a shapefile, then select all the 1s, and intersect these with the stream buffer and soils layer.

I knew it couldn't be that hard!