[GRASS-SVN] r70739 - grass-addons/grass7/raster/r.lfp

[svn_grass at osgeo.org]

Author: hcho
Date: 2017-03-10 21:06:28 -0800 (Fri, 10 Mar 2017)
New Revision: 70739

Modified:
   grass-addons/grass7/raster/r.lfp/r.lfp.py
Log:
r.lfp: thin output map; write metadata

Modified: grass-addons/grass7/raster/r.lfp/r.lfp.py
===================================================================
--- grass-addons/grass7/raster/r.lfp/r.lfp.py	2017-03-11 04:07:29 UTC (rev 70738)
+++ grass-addons/grass7/raster/r.lfp/r.lfp.py	2017-03-11 05:06:28 UTC (rev 70739)
@@ -58,6 +58,7 @@
 def calculate_lfp(input, output, coords):
     prefix = "r_lfp_%d_" % os.getpid()
 
+    # create the outlet vector map
     outlet = prefix + "outlet"
     p = grass.feed_command("v.in.ascii", overwrite=True,
             input="-", output=outlet, separator=",")
@@ -65,37 +66,42 @@
     p.stdin.close()
     p.wait()
     if p.returncode != 0:
-        grass.fatal(_("Cannot create outlet vector map"))
+        grass.fatal(_("Cannot create the outlet vector map"))
 
+    # convert the outlet vector map to raster
     try:
         grass.run_command("v.to.rast", overwrite=True,
                           input=outlet, output=outlet, use="cat", type="point")
     except CalledModuleError:
-        grass.fatal(_("Cannot convert outlet vector to raster"))
+        grass.fatal(_("Cannot convert the outlet vector to raster"))
 
+    # calculate the downstream flow length
     flds = prefix + "flds"
     try:
         grass.run_command("r.stream.distance", overwrite=True, flags="om",
-                          stream_rast=outlet, direction=input, method="downstream",
-                          distance=flds)
+                          stream_rast=outlet, direction=input,
+                          method="downstream", distance=flds)
     except CalledModuleError:
-        grass.fatal(_("Cannot create flow length downstream raster map"))
+        grass.fatal(_("Cannot calculate the downstream flow length"))
 
+    # calculate the upstream flow length
     flus = prefix + "flus"
     try:
         grass.run_command("r.stream.distance", overwrite=True, flags="o",
-                          stream_rast=outlet, direction=input, method="upstream",
-                          distance=flus)
+                          stream_rast=outlet, direction=input,
+                          method="upstream", distance=flus)
     except CalledModuleError:
-        grass.fatal(_("Cannot create flow length upstream raster map"))
+        grass.fatal(_("Cannot calculate the upstream flow length"))
 
+    # calculate the sum of downstream and upstream flow lengths
     fldsus = prefix + "fldsus"
     try:
         grass.run_command("r.mapcalc", overwrite=True,
                           expression="%s=%s+%s" % (fldsus, flds, flus))
     except CalledModuleError:
-        grass.fatal(_("Cannot create flds+flus raster map"))
+        grass.fatal(_("Cannot calculate the sum of downstream and upstream flow lengths"))
 
+    # find the longest flow length
     p = grass.pipe_command("r.info", flags="r", map=fldsus)
     max = ""
     for line in p.stdout:
@@ -105,19 +111,39 @@
             break
     p.wait()
     if p.returncode != 0 or max == "":
-        grass.fatal(_("Cannot find max flds+flus cell value"))
+        grass.fatal(_("Cannot find the longest flow length"))
 
     min = float(max) - 0.0005
 
+    # extract the longest flow path
+    lfp = prefix + "lfp"
     try:
-        grass.run_command("r.mapcalc",
-                          expression="%s=if(%s>=%f, 1, null())" % (output, fldsus, min))
+        grass.run_command("r.mapcalc", overwrite=True,
+                          expression="%s=if(%s>=%f, 1, null())" %
+                                     (lfp, fldsus, min))
     except CalledModuleError:
-        grass.fatal(_("Cannot create longest flow path raster map"))
+        grass.fatal(_("Cannot create the longest flow path raster map"))
 
-    grass.run_command("g.remove", flags="f",
-            type="raster,vector", pattern="%s*" % prefix)
+    # thin the longest flow path raster map
+    try:
+        grass.run_command("r.thin", input=lfp, output=output)
+    except CalledModuleError:
+        grass.fatal(_("Cannot thin the longest flow path raster map"))
 
+    # remove intermediate outputs
+    grass.run_command("g.remove", flags="f", type="raster,vector",
+                      pattern="%s*" % prefix)
+
+    # write history
+    tmphist = grass.tempfile()
+    f = open(tmphist, "w+")
+    f.write(os.environ["CMDLINE"])
+    f.close()
+
+    grass.run_command("r.support", map=output, title="Longest flow path",
+                      loadhistory=tmphist, description="generated by r.lfp")
+    grass.try_remove(tmphist)
+
 if __name__ == "__main__":
     options, flags = grass.parser()
     sys.exit(main())