DEM Elevation data

[William E Reid]

Just My 2 cents on the Subject.

DEMs are no longer readily available from places like usgs.  I am not 
really sure why.  They are the easiest to work with (ie convert).

If you are in the States....

at http://seamless.usgs.org you can download 3arc and 1arc second 
terrain data.  It comes in ArcGrid Format.  Though I have not seen a way 
to do this, I will be looking to convert them to geotiffs and shape 
files and dems with less granularity.

A geotiff loads quickly and gives the best performance in mapserver 
(from my experience anyway) if you are just looking to make things look 
more interesting.

Actually, you can download the data in Geotiff format, which is what I 
would recommend....  These might be more then what you want for 
granularity, I only dealt with 3arc and above data.

National Elevation Dataset.  I love em.

Your Tiff? Make sure it is a geotiff.  It needs to know where it is on 
the map.  If you disable TRANFORM (set it to false) in your layer it 
will probably show up.  But it needs to be a geotiff to show up properly.

Hope that helps.

-=Bill


Jerl Simpson wrote:
> Hi guys,
> 
> I am wanting to add DEMs or some elevation/contour maps to my maps. 
> But I am curious what works best with Mapserver.  I have found several
> different resource, but am at a loss as to which one I need.
> 
> The first one I tried, which was to download JPEG images and convert
> them to TIFF images, never actually show up as a layer.  This may be a
> format issue on my part.  I haven't dug into that yet.
> 
> I found one that is a ETOPO2 Global 2-Minute Gridded Elevation Data. 
> But I don't know what that is and not sure if it can be used.  If
> someone knows a trick, I'd be please to find out.
> 
> Similar issue with GLOBE files from NOAA.  Not sure if I can convert
> them to a format that's useful to use with Mapserver.
> 
> I'm sure there are other options, I just haven't found them.
> 
> I appreciate any help anyone might be able to give.
> 
> Thank you,
> 
> Jerl
>