topic Re: Contour tool - empty attribute table in ArcGIS Spatial Analyst Questions

Contour tool - empty attribute table

CamillaSanticoli1 — Thu, 09 Oct 2014 08:00:06 GMT

Hi all! I am trying to create contour lines from a DEM. When I execute the function with the spatial analyst tool it says that it has done it correctly but no contours are displayed and if I try to open the table of attribute it's empty. What could be the problem?

Thank you:)

Re: Contour tool - empty attribute table

DallasShearer — Thu, 09 Oct 2014 19:39:21 GMT

check your parameters, if your start contour level is not within the range of the DEM values and your interval to draw the contours from the start point also miss the values that fall in the range of the DEM then you would end up with an empty dataset.

Re: Contour tool - empty attribute table

DanPatterson_Retired — Thu, 09 Oct 2014 20:19:46 GMT

Also, have a good read through Contour Spatial Analyst help section...there a lot of caveats. An try running the tool without a base contour specified...it is optional...and let SA do the work

Re: Contour tool - empty attribute table

CamillaSanticoli1 — Fri, 10 Oct 2014 06:05:40 GMT

Thank you for the reply!Actually I am not defining any initial contour level, I am only defining the distance at which I want my contours. My DEM is going from 1414 m to 2674 m. How can check if the interval of contours fall within the exact range? Thank you

Re: Contour tool - empty attribute table

CamillaSanticoli1 — Fri, 10 Oct 2014 08:05:07 GMT

I never set the base contour. But it hasn't worked anyway!

Re: Contour tool - empty attribute table

DanPatterson_Retired — Fri, 10 Oct 2014 09:17:20 GMT

right-click on the raster, select Properties, then examine within there the min and max...alternately, you can find out the min and max from the symbology. if there is no data range listed, or it is outside the desired range, then something may be wrong with the raster. This of course assumes that the raster you are trying to contour has X, Y and Z in the same units which should be meters (or sometimes in feet in the case of the U.S)

Re: Contour tool - empty attribute table

CamillaSanticoli1 — Fri, 10 Oct 2014 09:40:19 GMT

the raster has a minimum of 979 m and a maximum of 2751 m...which is reasonable. I can see the table of attribute of my raster but then I cannot see anything if I try to compute the contours. I tried everthing but I don't know what's wrong.

Thanks

Re: Contour tool - empty attribute table

DanPatterson_Retired — Fri, 10 Oct 2014 10:21:31 GMT

bizzare...copy the raster to a simple folder c:/test/myraster, start a new project, add the raster, run the contour specifying the destination folder the same as the aforementioned, call it X just so you rule out any filenaming issues.

Option 2, try to contour a different raster

Re: Contour tool - empty attribute table

CamillaSanticoli1 — Fri, 10 Oct 2014 11:13:40 GMT

Thank you very much. I just figure out that with another raster it creates contour without problem so maybe it's just that one that has something wrong, but at least the tool works properly!