topic Re: Arc Hydro LEVEL DEM Z Value Error in Water Resources Questions

Arc Hydro LEVEL DEM Z Value Error

RajatChopra — Wed, 01 May 2013 18:16:52 GMT

Hello, I have started using Arc Hydro and was following tutorial by esri to learn arc hydro, But when i click LEVEL DEM i get an error stating that "Spatial reference does not have a Z Unit". I tried making changes in adf.prj file where my DEM file was present as my DEM was in UTM i tried making Z Units to 1 m or 100 cm but still I get this error .
Could you please help.??

Re: Arc Hydro LEVEL DEM Z Value Error

ChristineDartiguenave — Tue, 18 Jun 2013 15:24:10 GMT

Can you post your projection file?

Christine Dartiguenave
Esri Water Resources Team

Re: Arc Hydro LEVEL DEM Z Value Error

ChristineDartiguenave — Wed, 09 Oct 2013 22:12:25 GMT

It looks like the culprit is the auxiliary grid file. If a projection is specified in that file, it will be used to update the prj file when the grid gets added to ArcMap. This file is usually located in the same directory as the grid directory (as long as it is writable) and named grid.aux.xml where grid is the grid name. It contains information associated to the grid that cannot be stored with the grid itself.

http://resources.arcgis.com/en/help/...00000027000000

You can set the correct zunit in the auxiliary file by using the geoprocessing tool Define Projection and specifying the Z Coordinate System as well. Then either pick an existing one or create your own.
In the Vertical Coordinate System Properties window you will have the option to specify 1/ZUnit under Linear Unit. You can pick an existing unit (e.g. feet, decimeter, etc.) and see the corresponding value for 1/zunit (e.g. centimers = 0.01 meters/centimeters corresponding to zunit=100 in projection file).

The tool will edit both the auxiliary file and the xml.

Christine Dartiguenave
Esri Water Resources Team