DEM Elevation data

Wed Jun 15 12:49:16 PDT 2005

Bill,

gdalinfo is REALLY awesome.  I found that you can run it on a geotiff
from one of my searches.  I get pretty much the same info, except I
have nothing for coordinate system.

Driver: GTiff/GeoTIFF
Size is 3528, 4282
Coordinate System is `'
Origin = (230371.000000,1370761.000000)
Pixel Size = (1000.00000000,-999.96746800)
Metadata:
  TIFFTAG_SOFTWARE=IMAGINE TIFF Support
Copyright 1991 - 1999 by ERDAS, Inc. All Rights Reserved
@(#)$RCSfile: etif.c $ $Revision: 1.9.1.3 $ $Date: 2002/07/29 15:39:06EDT $
  TIFFTAG_XRESOLUTION=1
  TIFFTAG_YRESOLUTION=1
  TIFFTAG_RESOLUTIONUNIT=1 (unitless)
Corner Coordinates:
Upper Left  (  230371.000, 1370761.000) 
Lower Left  (  230371.000,-2911099.698) 
Upper Right ( 3758371.000, 1370761.000) 
Lower Right ( 3758371.000,-2911099.698) 
Center      ( 1994371.000, -770169.349) 
Band 1 Block=3528x2 Type=Byte, ColorInterp=Red
Band 2 Block=3528x2 Type=Byte, ColorInterp=Green
Band 3 Block=3528x2 Type=Byte, ColorInterp=Blue

That's pretty much the way may layer looks.  I've played around with
the projection a bit, but no luck.

This is what my map looks like on a globabl scale with that layer on:

http://mapserver1.rkiq.com/workshop/World11188387357318.gif

I'm sure there's a way to scale it, but just haven't been able to work
it out yet.
My layer looks like:

LAYER
    NAME "US_Relief"
    TRANSFORM FALSE
    DATA "89014205.tif"
    TYPE RASTER
    STATUS DEFAULT
    PROJECTION
      "init:epsg=9820"
      "proj=laea"
      "lat_0=-100"
      "lon_0=45"
      "x_0=0"
      "y_0=0"
      "units=m"
    END
  END

Thanks,

jerl

On 6/15/05, William E Reid <wer at cstone.net> wrote:
> Jerl,
> 
> 
> 
>         I have only used geotiffs that I have made.  They are geotiff/TAB
> format.  But your LAYER should be very simple as far as  I know.  This
> worked for me....
> 
>          LAYER
>            NAME "geotiff"
>            TYPE RASTER
>            STATUS ON
>            DATA "geotiff/65729931.tif"
>          END
> 
> 
> All the magic (aside from the wonderful things mapsserver does for
> us...) is stored in the TIF or TAB depending on what type of geotiff you
> have.
> 
> You should be able to run 'gdalinfo <file.tif>' on the tif file and it
> should reveal coordinates stored in the tif (or accompanying tab file).
> 
> Be sure to read the man page on gdalinfo.....
> 
> gdalinfo --formats
> 
> will show you what formats are supported (ie. did I forget to compile in
> geotiff support....?)
> 
> Make sure your extents are set to display what is in the tiff ( are you
> looking at it on the currently displayed map, or are you looking at a
> peiece of farm equipment?  You extents need to encompass the tiff or
> part of it...)
> 
> $ gdalinfo 65729931.tif
> Driver: GTiff/GeoTIFF
> Size is 300, 3300
> Coordinate System is:
> GEOGCS["NAD83",
>      DATUM["North_American_Datum_1983",
>          SPHEROID["GRS 1980",6378137,298.2572221010042,
>              AUTHORITY["EPSG","7019"]],
>          AUTHORITY["EPSG","6269"]],
>      PRIMEM["Greenwich",0],
>      UNIT["degree",0.0174532925199433],
>      AUTHORITY["EPSG","4269"]]
> Origin = (-78.083333,37.000000)
> Pixel Size = (0.00027778,-0.00027778)
> Metadata:
>    TIFFTAG_SOFTWARE=IMAGINE TIFF Support
> Copyright 1991 - 1999 by ERDAS, Inc. All Rights Reserved
> @(#)$RCSfile: etif.c $ $Revision: 1.9.1.3 $ $Date: 2002/07/29 15:39:06EDT $
>    TIFFTAG_XRESOLUTION=1
>    TIFFTAG_YRESOLUTION=1
>    TIFFTAG_RESOLUTIONUNIT=1 (unitless)
> Corner Coordinates:
> Upper Left  ( -78.0833333,  37.0000000) ( 78d 5'0.00"W, 37d 0'0.00"N)
> Lower Left  ( -78.0833333,  36.0833333) ( 78d 5'0.00"W, 36d 5'0.00"N)
> Upper Right ( -78.0000000,  37.0000000) ( 78d 0'0.00"W, 37d 0'0.00"N)
> Lower Right ( -78.0000000,  36.0833333) ( 78d 0'0.00"W, 36d 5'0.00"N)
> Center      ( -78.0416667,  36.5416667) ( 78d 2'30.00"W, 36d32'30.00"N)
> Band 1 Block=300x6 Type=Float32, ColorInterp=Gray
> 
> 
> Hope that helps.
> 
> -=Bill
> 
> 
> Jerl Simpson wrote:
> > Would you mind sharing your LAYER definition?  I have the file, but
> > can't seem to get it to display properly.  It's scale is wrong or
> > something and I can't get it worked out.  I see the layer, but can't
> > really tell what I'm looking at.
> >
> > I appreciate it.
> >
> > jerl
> >
> > On 6/14/05, William E Reid <wer at cstone.net> wrote:
> >
> >>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
> >>>
> >>
> >>
> >
> 
>