[GRASS-SVN] r60359 - grass/trunk/scripts/v.report

[svn_grass at osgeo.org]

Author: hcho
Date: 2014-05-19 20:32:42 -0700 (Mon, 19 May 2014)
New Revision: 60359

Modified:
   grass/trunk/scripts/v.report/v.report.py
Log:
v.report: cat mismatch bug fixed.

How to reproduce the bug

1. Merge multiple lines into polylines:
   v.build.polylines input=lines output=polylines cat=first

   lines attribute table is copied to polylines attribute table, but not all
   records have associated polyline features because only first attribute was
   linked to a feature.

2. v.db.select -c map=polylines, which is called by v.report, returns all
   records, which then are stored in records1.

   E.g,. three lines 1, 2, and 3 are merged into a polyline 3. Attributes 1 and
   2 are orphaned.

   cat|desc
   1|
   2|
   3|new polyline

3. v.to.db -p map=polylines option=option... returns only attributes that are
   linked to features and they are stored in records2.

   E.g.,
   cat|length
   3|1000

4. Now, sorted records1 and sorted records2 may not have the same ordered cats
   or even len(records1) != len(records2).

5. v.report always reports cats starting from 1 to #features, which can be
   wrong, because records1 has all the records in the attribute table, but
   records2 only has a subset of records1. Zipping two lists of different
   sizes...

   E.g., 1 from v.db.select, new polyline|1000 from v.to.db

   cat|desc|length
   1|new polyline|1000



Modified: grass/trunk/scripts/v.report/v.report.py
===================================================================
--- grass/trunk/scripts/v.report/v.report.py	2014-05-20 03:11:33 UTC (rev 60358)
+++ grass/trunk/scripts/v.report/v.report.py	2014-05-20 03:32:42 UTC (rev 60359)
@@ -4,6 +4,7 @@
 #
 # MODULE:       v.report
 # AUTHOR(S):    Markus Neteler, converted to Python by Glynn Clements
+#               Bug fixed by Huidae Cho <grass4u gmail.com>
 # PURPOSE:      Reports geometry statistics for vector maps
 # COPYRIGHT:    (C) 2005, 2007-2009 by MN and the GRASS Development Team
 #
@@ -67,9 +68,8 @@
         grass.fatal(_("Vector map <%s> not found") % mapname)
 
     colnames = grass.vector_columns(mapname, layer, getDict = False, stderr = nuldev)
-    
-    if not colnames:
-        colnames = ['cat']
+#    if not colnames:
+#        colnames = ['cat']
 
     if option == 'coor':
         columns = ['dummy1','dummy2','dummy3']
@@ -124,7 +124,11 @@
         records2.sort()
 
         #make pre-table
-        records3 = [r1 + r2[1:] for r1, r2 in zip(records1, records2)]
+	# len(records1) may not be the same as len(records2) because
+	# v.db.select can return attributes that are not linked to features.
+        records3 = []
+        for r2 in records2:
+            records3.append(filter(lambda r1: r1[0] == r2[0], records1)[0] + r2[1:])
     else:
         records1 = []
         p = grass.pipe_command('v.category', inp = mapname, layer = layer, option = 'print')