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How do I know if the DEM contains z-values?

I am looking at the DEM's layer properties and it does not mention the z values.

I then add it to ArcScene and tried to find it without success.

It only shows the x,y values.

  • @PROBERT, when you identify a pixel does it give you the elevation value? – artwork21 May 11 '11 at 16:37
  • Yes, if you open attribute values it tells you but what about the z value ? – PROBERT May 11 '11 at 16:42
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    @PROBERT, the z-value is the elevation value. Is there a particular task you are wanting to do with these values? – artwork21 May 11 '11 at 17:21
  • No particular but Are all DEM suppose to have their z-values within the data ? – PROBERT May 11 '11 at 18:56
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    the dem without an elevation (z value) would not really even be a raster. in a raster you have the xy-s then you have a value (in picture rasters that would be a color value) In dems (which are just a raster with elevation) you have a value used for z. if the value doesn't represent z or if it is missing - that would IMO be no raster. I would also think tha tmost all software would throw an error with such a file. @PROBERT - I think you probably have a value in your dem. – Brad Nesom May 11 '11 at 20:52
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You should see a value which the image is stretched by when you add it to ArcMap, as in this:

screen shot

Then by switching to stretch type min-max you will see a more accurate elev value, as in this:

Screen shot2

which produces this:

Screen shot3

A nice touch then is to use the USGS color palette to show elev.

USGS

For this:

DEM Elev

  • Furthermore, you might need to "Add Statistics" so that the raster can be scaled to the correct range. – Mike T May 11 '11 at 19:31
  • When you select the min-max it asks if you want to allow histograms to be built. I think it uses the statistics from that and that is how it shows the correct min-max. but I assume statistics would work for other raster functions. – Brad Nesom May 11 '11 at 20:47

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