Extracting Elevation Data for Centroids

MattGillen · ‎10-04-2012

Hi there,

I apologize if this, or something similar, has been asked recently and if I'm not in the right forum for this issue.

I have a shapefile of every zip code in the United States. I have then broke it down by State and am focusing on New York right now. I want to import a DEM of New York and then take the centroid of each zip code and find the elevation. I'd like the elevation to then be an attribute within the zip code shapefile. I have the centroids as a lat/lon coordinate given int he zip code shapefile.

Currently, I do not have a DEM file on New York, and wanted to see if this was possible to due before trying to get one. If any of you have another idea on how to get the elevation of a centroid, please feel free to suggest it as I am open to different ways of doing this, as I will be needing to do this for 25-30 states.

Thank you so much for any help you can provide!

Matt

JonathanQuinn · ‎10-04-2012

Check out the answer to your other post here.

JeffreyEvans · ‎10-04-2012

Is there any particular reason that you need the elevation for the centroid. You could take the mean elevation for each zip code polygon using "Zonal Statistics as Table" (http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z000000w8000000.htm) and then join the table back to the polygons.

MattGillen · ‎10-04-2012

Jevans02,

The mean would actually be more useful for my end goal. I would still need a DEM, right? Or is there another way to get elevation data? The shapefile with the zip codes does not have any elevation data included.

Thanks for the idea!

JeffreyEvans · ‎10-04-2012

Yes, you will still need a DEM (elevation raster). Two common sources for the US are:

The National Map (USGS NED)
http://nationalmap.gov/

USDA-NRCS Geospatial Data Gateway
http://datagateway.nrcs.usda.gov/

MattGillen · ‎10-05-2012

Thanks for the links! This also means I would need the Spatial Analyst extension of ArcMap, correct? Or is there another way to go about doing this. I have the spatial analyst, but am curious if there is a better option.

Thanks again!