[GRASS-user] dxf / v.report puzzle
sedwards2 at cinci.rr.com
Sat Jun 7 10:31:56 EDT 2008
I am processing some geotechnical data that is geolocated on a CAD
drawing (Bentley dgn is the original pedigree).
This has been exported as a dxf file and brought into GRASS with
v.in.dxf -- no problem.
The region is set up in state plane coordinates (KY-N) with US survey
feet as units.
When I run v.report on the layer that contains the boring data the
file content is displayed, for example:
Using 5B-305 as an example, when I display the points and query using
v.what, it produces:
Point height: 0.000000
Key column: cat
cat : 38
layer : G_PF_SYMB3_PR
entity : text
These coordinates bear little resemblance to the v.report values.
Opening the dxf file in an editor and poking about, I found what
appears to be the data set for 5B-305 (it is the only time 5B-305
appears in the file):
1 1 Plan
These correspond fairly well to the values produced by v.what.
The question for anyone patient enough to still be with me is -- what
is v.report reporting? There appears to be no pattern to the dx and
dy between the two reports over a reasonable sampling of the borings.
Partial answer! I was about to hit the send button, but decided first
to run a search in the dxf file for the coordinates that are shown in
v.report. To my surprise there was one hit:
1 1 Plan
The coordinates for 5B-305 in v.report are actually those of 5B-329!
So the data appear to be shuffled rather than distorted.
Thanks for any help you can provide ~
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