[GRASS-user] dxf / v.report puzzle

[Stuart Edwards]

Greetings -

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:

37|G_PF_SYMB3_PR|text|5B-303|1212081.497014|279650.475464|0
38|G_PF_SYMB3_PR|text|5B-305|1211936.354207|279753.605789|0
39|G_PF_SYMB3_PR|text|5B-306|1211736.052427|279843.95891|0

Using 5B-305 as an example, when I display the points and query using  
v.what, it produces:

East: 1212909.91005291
North: 279431.95238095

Map: borings
Mapset: PERMANENT
Type: Point
Line: 58
Point height: 0.000000
Layer: 3
Category: 38

Driver: dbf
Database: /Users/stu/grassdata/Kennedy_SPC/PERMANENT/dbf/
Table: borings_g_pf_symb3_pr
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):

AcDbEntity
   8
G_PF_SYMB3_PR
100
AcDbText
  10
1212909.151125       **
  20
279430.832539          **
  30
0.0
  40
12.0
   1
5B-305                          **
  50
7.581985
   7
1 1 Plan
100


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:

AcDbEntity
   8
G_PF_SYMB3_PR
100
AcDbText
  10
1211936.354207 	**
  20
279753.605789		**
  30
0.0
  40
12.0
   1
5B-329				**
  50
7.581985
   7
1 1 Plan
100

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 ~

Stu
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