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| GeoCommunity Mailing List |
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| Mailing List Archives |
| Subject: | GISList: DEM to XYZ? |
| Date: |
02/13/2002 07:37:16 AM |
| From: |
Travis G. Smith |
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Hi Listers,
I am seeking an alternative approach for converting DEM (.dem) files to
an ASCII X/Y/Z format (or similarly compatible format such as DBF,
Excel, etc...). We have used the procedure listed below successfully by
utilizing Arc/Info, however, we need an alternative approach. We would
like to be able to do this conversion without the use of Arc/Info and
preferably with the use of existing shareware or inexpensive programs.
If anyone has any ideas, would you please let me know?
Thanks in advance,
Travis
>>>
The Mt. Hood XYZ Project will entail the production of two ASCII X/Y/Z
(point cloud) files from two (2) existing DEMs. The two existing DEM
files are both 10M DE-DEMs in USGS Level 2 format. These DEMs are in UTM
coordinates, zone 10: datum is NAD-27: units are in meters: and Z-units
are in decimeters.
The objective of this project is to convert the DEM files to ARC/INFO
GRID (ARC/INFO 7.2.1) format using the ‘DEMLATTICE’ command. Within this
conversion to GRID format, a ‘z_factor’ parameter of 10.0 will be used
in order to convert the Z-units from decimeters to whole meters,
synonymous with the X and Y units. Second, the resulting GRID file will
be converted to a vector point coverage using the ‘GRIDPOINT’ command.
This command generates a point at the centroid of each pixel except
where a value of ‘0’ or ‘NODATA’ is found. The X and Y coordinates for
each point are then joined with the Z coordinates in the Point Attribute
Table via the command ‘ADDXY’.
Once ARC/INFO processing is complete, final text editing is performed
within ArcView 3.2. Using the table editing interface, all unnecessary
Items are removed: the required Items are re-ordered to X/Y/Z, and
finally all records are exported to ASCII text file format for delivery.
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