[GRASS-SVN] r45895 - grass/trunk/doc/python
svn_grass at osgeo.org
svn_grass at osgeo.org
Sun Apr 10 17:47:05 EDT 2011
Author: martinl
Date: 2011-04-10 14:47:05 -0700 (Sun, 10 Apr 2011)
New Revision: 45895
Modified:
grass/trunk/doc/python/m.distance.py
Log:
m.distance: major update for ctypes
Modified: grass/trunk/doc/python/m.distance.py
===================================================================
--- grass/trunk/doc/python/m.distance.py 2011-04-10 21:12:17 UTC (rev 45894)
+++ grass/trunk/doc/python/m.distance.py 2011-04-10 21:47:05 UTC (rev 45895)
@@ -1,206 +1,149 @@
-#!/usr/bin/python
+#!/usr/bin/env python
############################################################################
#
# MODULE: m.distance
#
# AUTHOR(S): Hamish Bowman, Dunedin, New Zealand
+# Updated for Ctypes by Martin Landa <landa.martin gmail.com>
#
# PURPOSE: Find distance between two points
# If the projection is latitude-longitude, this distance
# is measured along the geodesic.
-# Demonstrates GRASS SWIG-Python interface
+# Demonstrates GRASS Python Ctypes interface
#
-# COPYRIGHT: (c) 2008 Hamish Bowman, and The GRASS Development Team
+# COPYRIGHT: (c) 2008, 2011 Hamish Bowman, and the GRASS Development Team
#
-# This program is free software under the GNU General Public
-# License (>=v2). Read the file COPYING that comes with GRASS
-# for details.
+# This program is free software under the GNU General
+# Public License (>=v2). Read the file COPYING that
+# comes with GRASS for details.
#
############################################################################
#
-# Requires GRASS SWIG-Python interface
+# Requires GRASS Python Ctypes interface
# Requires Numeric module (NumPy) from http://numpy.scipy.org/
# Requires NumPrt module from http://geosci.uchicago.edu/csc/numptr/
#
-"""
- **** FIXME: needs to be ported from SWIG to Ctypes! ****
-"""
+#%module
+#% label: Finds the distance between two or more points.
+#% description: If the projection is latitude-longitude, this distance is measured along the geodesic.
+#% keywords: miscellaneous, distance, measure
+#%end
+#%option
+#% key: coord
+#% type: string
+#% required: yes
+#% multiple: yes
+#% key_desc: easting,northing
+#% description: Comma separated list of coordinate pairs
+#%end
+#%flag
+#% key: i
+#% description: Read coordinate pairs from stdin
+#% suppress_required: yes
+#%end
-
-#%Module
-#% label: Finds the distance between two or more points.
-#% description: If the projection is latitude-longitude, this distance is measured along the geodesic.
-#% keywords: miscellaneous, distance, measure
-#%End
-#%Option
-#% key: coord
-#% type: string
-#% required: no
-#% multiple: yes
-#% key_desc: x,y
-#% description: Comma separated list of coordinate pairs
-#%End
-#%Flag
-#% key: i
-#% description: Read coordinate pairs from stdin
-#%End
-
-
import os, sys
-if not os.environ.has_key("GISBASE"):
- print "You must be in GRASS GIS to run this program."
- sys.exit(1)
+import grass.script as grass
+from grass.lib.gis import *
def main():
+ G_gisinit('m.distance')
- #### add your code here ####
-
- # 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")
- from grass.lib import gis as g7lib
-
- # for passing pointers
- import Numeric
- import NumPtr
-
- g7lib.G_gisinit('m.distance')
- # returns 0 on success
-
-
- ### calc distance ###
+ # calc distance
- proj_type = g7lib.G_begin_distance_calculations()
+ proj_type = G_begin_distance_calculations()
# returns 0 if projection has no metrix (ie. imagery)
# returns 1 if projection is planimetric
# returns 2 if projection is latitude-longitude
-
# parser always creates at least an empty variable, and sys.argv is
- # toast, so no way to check if option was given. So it hangs if
- # --q was the only option given and there is no data from stdin.
- coord_ans = os.getenv("GIS_OPT_COORD")
- stdin_flag = bool(int(os.getenv("GIS_FLAG_I")))
-
- if stdin_flag is True:
- coords = []
+ # toast, so no way to check if option was given. So it hangs if
+ # --q was the only option given and there is no data from stdin.
+ coords = []
+ if flags['i']:
# read line by line from stdin
- while 1:
+ while True:
line = sys.stdin.readline().strip()
- if not line: # EOF
+ if not line: # EOF
break
else:
- coords += line.split(',')
+ coords.append(line.split(','))
else:
# read from coord= command line option
- coords = coord_ans.split(',')
-
-
- if len(coords) < 4:
- print "A minimum of two input coordinate pairs are needed"
- return
-
-
+ p = None
+ for c in options['coord'].split(','):
+ if not p:
+ p = [c]
+ else:
+ p.append(c)
+ coords.append(p)
+ p = None
+
+ if len(coords) < 2:
+ grass.fatal("A minimum of two input coordinate pairs are needed")
+
# init variables
overall_distance = 0.0
-
+ coord_array = c_double * len(coords)
+ x = coord_array()
+ y = coord_array()
if proj_type == 2:
# lat/lon scan for DDD:MM:SS.SSSS
- easting = Numeric.array(0., Numeric.Float64)
- eastPtr = NumPtr.getpointer(easting)
- northing = Numeric.array(0., Numeric.Float64)
- northPtr = NumPtr.getpointer(northing)
-
- # TODO: for clarity, figure out how to replace "3" with
- # the defined LOCATION_LL constant from gis.i
- g7lib.G_scan_easting(coords[0], eastPtr, 3)
- g7lib.G_scan_northing(coords[1], northPtr, 3)
- x1 = float(easting)
- y1 = float(northing)
+ easting = c_double()
+ northing = c_double()
+ G_scan_easting(coords[0][0], byref(easting), PROJECTION_LL)
+ G_scan_northing(coords[0][1], byref(northing), PROJECTION_LL)
+ x[0] = float(easting.value)
+ y[0] = float(northing.value)
else:
- # plain old coordinates
- x1 = float(coords[0])
- y1 = float(coords[1])
-
- x = [x1]
- y = [y1]
-
- for i in range(1, (len(coords) / 2)):
-
+ # plain coordinates
+ x[0] = float(coords[0][0])
+ y[0] = float(coords[0][1])
+
+ for i in range(1, len(coords)):
if proj_type == 2:
- g7lib.G_scan_easting (coords[ i*2 + 0 ], eastPtr, 3)
- g7lib.G_scan_northing(coords[ i*2 + 1 ], northPtr, 3)
- x2 = float(easting)
- y2 = float(northing)
+ easting = c_double()
+ northing = c_double()
+ G_scan_easting(coords[i][0], byref(easting), PROJECTION_LL)
+ G_scan_northing(coords[i][1], byref(northing), PROJECTION_LL)
+ x[i] = float(easting.value)
+ y[i] = float(northing.value)
else:
- x2 = float(coords[ i*2 + 0 ])
- y2 = float(coords[ i*2 + 1 ])
-
- segment_distance = g7lib.G_distance(x1, y1, x2, y2)
+ x[i] = float(coords[i][0])
+ y[i] = float(coords[i][1])
+
+ segment_distance = G_distance(x[i-1], y[i-1], x[i], y[i])
overall_distance += segment_distance
-
+
print "segment %d distance is %.2f meters" % (i, segment_distance)
-
+
# add to the area array
-
- # setup for the next loop
- x1 = x2
- y1 = y2
-
- x += [x2]
- y += [y2]
-
- print
- print " total distance is %.2f meters" % overall_distance
- print
-
-
- ### calc area ###
- if len(coords) < 6:
- return
-
- g7lib.G_begin_polygon_area_calculations()
+
+ print "\ntotal distance is %.2f meters\n" % overall_distance
+
+ # calc area
+ if len(coords) < 3:
+ return 0
+
+ G_begin_polygon_area_calculations()
# returns 0 if the projection is not measurable (ie. imagery or xy)
# returns 1 if the projection is planimetric (ie. UTM or SP)
# returns 2 if the projection is non-planimetric (ie. latitude-longitude)
# do not need to close polygon (but it doesn't hurt if you do)
- npoints = len(x)
-
- # unset variables:
- #del [Xs, Xptr, Ys, Yptr]
- # or
- #Xs = Xptr = Ys = Yptr = None
-
- Xs = Numeric.array(x, Numeric.Float64)
- Xptr = NumPtr.getpointer(Xs)
- Ys = Numeric.array(y, Numeric.Float64)
- Yptr = NumPtr.getpointer(Ys)
+ area = G_area_of_polygon(x, y, len(coords))
+ print "area is %.2f square meters\n" % area
- area = g7lib.G_area_of_polygon(Xptr, Yptr, npoints)
- print "AREA: %10.2f square meters" % area
- print
-
-
# we don't need this, but just to have a look
- if False:
- if proj_type == 1:
- g7lib.G_database_units_to_meters_factor()
- # 1.0
- print "Location units are", g7lib.G_database_unit_name(True)
+ if proj_type == 1:
+ G_database_units_to_meters_factor()
+ grass.message("Location units are %s" % G_database_unit_name(True).lower())
+
+ return 0
-
- #### end of your code ####
- return
-
if __name__ == "__main__":
- if ( len(sys.argv) <= 1 or sys.argv[1] != "@ARGS_PARSED@" ):
- os.execvp("g.parser", [sys.argv[0]] + sys.argv)
- else:
- main();
-
+ options, flags = grass.parser()
+ sys.exit(main())
More information about the grass-commit
mailing list