[GRASSLIST:2264] Re: Another incomplete DEM file (fwd)

Fri Aug 3 17:09:08 EDT 2001

  This may be old hat to most of you, but I hadn't seen all this information
before. The sender, Elizabeth McCartney, just called to tell me that they'll
fix the two incomplete SDTS tarballs as soon as they can download them from
GeoComm. :-)

  Excellent response by the USGS, and a request from them to be notified of
other problem quads. Nice to see tax money well spent.

Rich

Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
            2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
 + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard at appl-ecosys.com
                 Making environmentally-responsible mining happen.

---------- Forwarded message ----------

Hello Dr. Shepard,

Below is the information we discussed earlier today.

The U.S. Geological Survey (USGS) has entered into an agreement with the
GeoCommunity to serve updated, SDTS format, Digital Elevation Models
(DEMs) through the GIS Data Depot at http://www.gisdatadepot.com for no charge.  The 7.5' SDTS DEM data are also available for purchase
via premium (fast) download and on CD-ROM from GeoCommunity.

USGS distribution of SDTS DEMs through Earth Explorer has been
discontinued.  A link to the GIS Data Depot from the USGS Geographic Data
Download Web site, http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/ndcdb.html , provides direct access to SDTS DEMs for customers coming to the USGS
for these files.

The decision to provide SDTS DEMs through the GIS Data Depot is consistent
with the USGS goal of making more public domain data available at no
charge while enabling the private sector to have a greater role in the
distribution of USGS data.  SDTS DEMs placed on media in response to
customer orders will be sold by the GeoCommunity at a price less than the
USGS currently charges.

The GeoCommunity will continue to receive SDTS versions of the DEMs as
they are made available by the USGS.  Native format DEMs are still
available for sale from USGS on various media and via ftp.

In addition to correcting positional errors, the draft SDTS Raster Profile
was replaced during the conversion process.  Some slight differences exist
between the two standards which may (if hard coded in GIS software from
the draft standard) cause application failures when using with the new
SDTS DEMs.  Below is a list of some of the differences.  We are currently
investigating an initial work around.

A. The differences between pre and post jan2001SDTS DEMs:

  1)The Profile Identification PRID subfield in the xxxxIDEN.DDF:
      pre  jan2001 have PRID of "SDTS RASTER PROFILE"
      post jan2001 have PRID of "SRPE: RASTER PROFILE and EXTENSIONS"

2)Data type for CEL0 values of SDTS DEMs:
     pre jan2001 z-units were in feet or meters .....data type BI16.
     post jan2001 z-units can be feet, meters or decimal meters....
                       data type can be BI16 (feet or meters)
                       or BFP32 (for decimal meter)

B. The Sol Katz sdts2dem/sdtsedem .exe's does not work on the SDTS decimal
meter DEMs.
     Also, the sdtsedem/sdts2dem .exe's (versions .011 and .012) have map
boundary info in the pre-2001 SDTS DEMs, but incorrect/missing boundary
numbers in the post-2001 SDTS DEMS .... along with incorrect z-values...

C. ArcView 3.2/ERDAS Imagine 8.4 does not recognize PRID of SRPE: RASTER
PROFILE and EXTENSIONS as a
     valid SDTS Profile. There is no problem with ArcInfo8 and
ArcView8...ArcToolbox works OK.

D. DLGv32 does not display SDTS decimal meter DEMs correctly...color
stretch/z values incorrect.

E.  Software vendors that support the new SDTS DEMs with z-units of feet,
meters, and decimal meters:
     ArcInfo 8, ArcView 8 via ArcToolbox.
    ArcView3.2 (requires editing of xxxxIDEN.DDF----contact me if you
would like to try the test work-around)
    ERDAS Imagine 8.4 (requires editing of xxxxIDEN.DDF---contact me if
you would like to try the test work-around )
    Manifold 5
    FME
    3DEM
    MicroDEM

Please monitor the following websites for updates regarding the new
changes.

http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/ndcdb.html

and

http://mcmcweb.er.usgs.gov/sdts/

Free native format DEMs:  The sites below have been forwarded to me from
other users.  Use the data from these sites at your own risk.  I do not
know if these are the most current DEMs or if they are in the original
native USGS DEM format or if they have been translated from SDTS to the
native format.  The most current DEMs continue to be at GeoCommunity in the SDTS format or
purchased from the USGS in the Native format.

http://lighthouse.nrcs.usda.gov/gateway/NextPage.asp

or

http://www.webmet.com/terrain75min.html

Another web site with links to all kinds of free data is

http://www.cast.uark.edu/local/hunt/

We appreciate your comments and understand your concern.   The
relationship with GeoComm is not an exclusive one, and I expect to see
others hosting the USGS SDTS DEMs in the near future.  Please send any
additional comments or questions to sdts at usgs.gov, or if you prefer, to me
directly.

Sincerely,

Elizabeth McCartney
USGS Earth Science Information Center
1400 Independence Road
Rolla, MO  46501

Voice:   573-308-3696
Fax:      573-308-3615

"Hylan L Beydler" <hbeydler at usgs.gov>
Sent by: owner-sdts at savitar.er.usgs.gov
08/03/2001 07:22 AM

        To:     sdts at savitar.er.usgs.gov
        cc:
        Subject:        Another incomplete DEM file

Date: Thu, 2 Aug 2001 20:01:47 -0700 (PDT)
From: Rich Shepard <rshepard at appl-ecosys.com>

  The Congress Canyon 7.5-minute quadrangle DEM (in Nevada) is also
incomplete:

[rshepard at salmo coeur]$ tar xzvf congress_canyon.tar.gz
README
1418CATD.DDF
1418CATS.DDF
1418CEL0.DDF

gzip: stdin: unexpected end of file
tar: Unexpected EOF on archive file
tar: Child returned status 1
tar: Error exit delayed from previous errors

  Please fix these as I need them for a project. You can attach them to an
e-mail directly to me, please so I can use them as soon as they are
complete.

  While I have your attention, why do so many different (but adjacent quad
DEMS untar to the same file names? The Congress Canyon is the fourth one
today that untarred to 1418.

Thanks,

Rich

Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
            2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
 + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) |
rshepard at appl-ecosys.com
                 Making environmentally-responsible mining happen.