initial clean of ctypes vector example

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@44818 15284696-431f-4ddb-bdfa-cd5b030d7da7

doc/python/vector_example_ctypes.py

@@ -1,101 +1,72 @@
 #!/usr/bin/python
 
-# run within GRASS Spearfish session
-# run this before starting python to append module search path:
-#   export PYTHONPATH=$PYTHONPATH:/usr/local/grass-7.0.svn/etc/python
-#   check with "import sys; sys.path"
-# or:
-#   sys.path.append("/usr/local/grass-7.0.svn/etc/python")
-
-"""
-     ****  FIXME: needs to be ported from SWIG to Ctypes!  ****
 """
+Sample Python script to access vector dada using GRASS Ctypes interface
 
+Run this before starting python to append module search path:
+   export PYTHONPATH=$PYTHONPATH:/usr/local/grass-7.0.svn/etc/python
+check with "import sys; sys.path"
+
+or
+   sys.path.append("/usr/local/grass-7.0.svn/etc/python")
+"""
 
 import os, sys
-from grass.lib import grass
-from grass.lib import vector as grassvect
-import grass.script as grassscript
+
+from grass.lib.grass  import *
+from grass.lib.vector import *
 
 if not os.environ.has_key("GISBASE"):
-    print "You must be in GRASS GIS to run this program."
-    sys.exit(1)
+    sys.exit("You must be in GRASS GIS to run this program.")
 
-if len(sys.argv)==2:
+if len(sys.argv) == 2:
   input = sys.argv[1]
 else:
   input = raw_input("Vector Map Name? ")
 
-# initialize
-grass.G_gisinit('')
+# initialize GRASS library
+G_gisinit('')
 
-# find map in search path
-mapset = grass.G_find_vector2(input,'')
+# find vector map in the search path
+mapset = G_find_vector2(input, '')
+if mapset:
+    print "Vector map found in mapset <%s>" % mapset
+else:
+    sys.exit("Vector map <%s> not found" % input)
 
 # define map structure
-map = grassvect.Map_info()
+map = Map_info()
 
 # define open level (level 2: topology)
-grassvect.Vect_set_open_level (2)
+Vect_set_open_level(2)
 
-# open existing map
-grassvect.Vect_open_old(map, input, mapset)
+# open existing vector map
+Vect_open_old(map, input, mapset)
 
 # query
-print 'Vect map: ', input
-print 'Vect is 3D: ', grassvect.Vect_is_3d (map)
-print 'Vect DB links: ', grassvect.Vect_get_num_dblinks(map)
-print 'Map Scale:  1:', grassvect.Vect_get_scale(map)
+print 'Vect map: ',      input
+print 'Vect is 3D: ',    Vect_is_3d(map)
+print 'Vect DB links: ', Vect_get_num_dblinks(map)
+print 'Map Scale:  1:',  Vect_get_scale(map)
 
 # vector box tests
-box = grassvect.bound_box()
-c_easting1  =  599505.0
-c_northing = 4921010.0
-c_easting2  =  4599505.0
-
-grassvect.Vect_get_map_box(map, box)
-print 'Position 1 in box? ', grassvect.Vect_point_in_box(c_easting1, c_northing, 0, box)
-print 'Position 2 in box? ', grassvect.Vect_point_in_box(c_easting2, c_northing, 0, box)
-print 'Vector line 2 in box? ', grassvect.Vect_get_line_box(map, 2, box)
-# misleading:
-# print 'Number of lines:', grassvect.Vect_get_num_lines(map)
+box = bound_box()
+c_easting1  = 599505.0
+c_northing  = 4921010.0
+c_easting2  = 4599505.0
+
+Vect_get_map_box(map, box)
+print 'Position 1   in box? ', Vect_point_in_box(c_easting1, c_northing, 0, box)
+print 'Position 2   in box? ', Vect_point_in_box(c_easting2, c_northing, 0, box)
+print 'Feature id 2 in box? ', Vect_get_line_box(map, 2, box)
+
+print 'Number of features:', Vect_get_num_lines(map)
 # how to access GV_POINT?
 # print 'Number of points: ', grassvect.Vect_get_num_primitives(map,GV_POINT)
 # confusing:
 #print 'Number of lines: ', grassvect.Vect_get_num_primitives(map,GV_LINE)
 #print 'Number of areas:', grassvect.Vect_get_num_primitives(map,GV_AREA)
-print 'Number of areas:', grassvect.Vect_get_num_areas(map)
-
-layer = 1
-tmp = grassscript.tempfile()
-tmpf = file(tmp, 'w')
-
-try:
-    f = grassscript.vector_db(input)[int(layer)]
-except KeyError:
-    grassscript.fatal("There is no table connected to this map. Run v.db.connect or v.db.addtable first.")
-table = f['table']
-database = f['database']
-driver = f['driver']
-
-# call GRASS command
-grassscript.run_command('v.db.select', flags = 'c', map = input,
-                   stdout = tmpf)
-tmpf.close()
-
-# check if result is empty
-tmpf = file(tmp)
-if tmpf.read(1) == '':
-    grassscript.fatal("Table <%s> contains no data.", table)
-
-# print table to stdout
-for line in tmpf:
-    print line
-
-tmpf.close()
-os.remove(tmp)
+print 'Number of areas:',   Vect_get_num_areas(map)
 
 # close map
-grassvect.Vect_close(map)
-## end of the python script
-
+Vect_close(map)