Using ModelBuilder to create smaller individual DEMs from a large DEM using multiple polygon?

Question

How can I use a polygon (which is made up of smaller polygons) to create individual DEMs from a large DEM using the polygons as the mask/extent? I am trying to do this in ModelBuilder and it isn't working. I have a shapefile made up of lots of smaller polygons (each with their own attribute/number that looks like this:

I tried to use this in ModelBuilder by: Insert-Iterator-Feature selection. Then I used the shapefile 'poly' as the 'input features' and I grouped by field (station number). I then added the 'extract by mask' tool and choose my large DEM as the 'input raster'. Then I have to choose the feature mask data:Do I input the same polygon file that has the station number (below poly_Station number)? Finally I'm really not sure how to specify the naming convention OR the file type: eg. In the extract by mask output raster option, I am putting: C:\User\Documents\ArcGIS\Default.gdb\Extract_%value%.

Is %value% right here? Should I be including a file type also?

Here are the errors I am getting:

ERROR 999999: Error executing function. FDO error: -2147024894 FDO error: -2147024894 [GDB_SystemCatalog] No spatial reference exists. ERROR 010302: Unable to create the output raster: C:\Users\Documents\ArcGIS\Default.gdb\Extract_10002 ERROR 010067: Error in executing grid expression. Failed to execute (Extract by Mask). Failed at Mon Jun 13 16:51:00 2016 (Elapsed Time: 2.63 seconds)

Answer 1

Your model appears to be correct and you are using the %value% correctly, that is the ID of what your are calling your station number. The error message says you have no spatial reference, i.e. either your DEM or Polygon dataset are missing a defined coordinate system. So you need to make sure they have that set. Look into the Define Projection tool.

It would be advisable to have them in the same coordinate system. Don't try processing one dataset that is in WGS84 against something that is a national grid. I would probably convert the WGS84 dataset into the national grid.