Tell me more ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.
up vote 2 down vote favorite
1

How do I know if the DEM contains z-values ? By looking at the DEM's layer properties and it does not mention the z values. I then add it to the ArcScene and tried to find it..nothing...

It only shows the x,y values.

Thanks.

share|improve this question
@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
4  
@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
2  
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
show 3 more comments

1 Answer

up vote 4 down vote accepted

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 mni-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 pallette to show elev.

USGS

For this

DEM Elev

share|improve this answer
Furthermore, you might need to "Add Statistics" so that the raster can be scaled to the correct range. – Mike Toews 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

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.