[GRASS-SVN] r36479 - grass/trunk/vector/lidar/v.surf.bspline

[svn_grass at osgeo.org]

Author: neteler
Date: 2009-03-25 03:34:44 -0400 (Wed, 25 Mar 2009)
New Revision: 36479

Modified:
   grass/trunk/vector/lidar/v.surf.bspline/main.c
   grass/trunk/vector/lidar/v.surf.bspline/v.surf.bspline.html
Log:
merged parameter description fixes from previous HTML submission

Modified: grass/trunk/vector/lidar/v.surf.bspline/main.c
===================================================================
--- grass/trunk/vector/lidar/v.surf.bspline/main.c	2009-03-25 07:18:17 UTC (rev 36478)
+++ grass/trunk/vector/lidar/v.surf.bspline/main.c	2009-03-25 07:34:44 UTC (rev 36479)
@@ -86,7 +86,7 @@
     cross_corr_flag = G_define_flag(); {
 	cross_corr_flag->key = 'c';
 	cross_corr_flag->description =
-	    _("Find best parameters using a cross validation method");
+	    _("Find the best Tykhonov regularizing parameter using a \"leave-one-out\" cross validation method");
     }
 
     in_opt = G_define_standard_option(G_OPT_V_INPUT);
@@ -111,7 +111,7 @@
 	passoE_opt->required = NO;
 	passoE_opt->answer = "4";
 	passoE_opt->description =
-	    _("Interpolation spline step value in east direction");
+	    _("Length of each spline step in the east-west direction");
 	passoE_opt->guisection = _("Settings");
     }
 
@@ -121,7 +121,7 @@
 	passoN_opt->required = NO;
 	passoN_opt->answer = "4";
 	passoN_opt->description =
-	    _("Interpolation spline step value in north direction");
+	    _("Length of each spline step in the north-south direction");
 	passoN_opt->guisection = _("Settings");
     }
 
@@ -129,7 +129,7 @@
 	type->key = "type";
 	type->type = TYPE_STRING;
 	type->required = NO;
-	type->description = _("Spline type of interpolation");
+	type->description = _("Spline interpolation algorithm");
 	type->options = "bilinear,bicubic";
 	type->answer = "bilinear";
 	type->guisection = _("Settings");
@@ -139,7 +139,7 @@
 	lambda_f_opt->key = "lambda_i";
 	lambda_f_opt->type = TYPE_DOUBLE;
 	lambda_f_opt->required = NO;
-	lambda_f_opt->description = _("Tykhonov regularization weight");
+	lambda_f_opt->description = _("Tykhonov regularization parameter (affects smoothing)");
 	lambda_f_opt->answer = "1";
 	lambda_f_opt->guisection = _("Settings");
     }

Modified: grass/trunk/vector/lidar/v.surf.bspline/v.surf.bspline.html
===================================================================
--- grass/trunk/vector/lidar/v.surf.bspline/v.surf.bspline.html	2009-03-25 07:18:17 UTC (rev 36478)
+++ grass/trunk/vector/lidar/v.surf.bspline/v.surf.bspline.html	2009-03-25 07:34:44 UTC (rev 36479)
@@ -3,9 +3,9 @@
 Tykhonov regularization. The input is a 2D or 3D vector points map. Values to
 interpolate can be the z values of 3D points or the values in a user-specified
 attribue column in a 2D or 3D map. Output can be a raster or vector map.
-Optionally, a "sparse point" vector map can be input specify vector points
-output.
-<br> <br>
+Optionally, a "sparse point" vector map can be input which indicates the
+location of <b><i>output</i></b> vector points.
+<p>
 From a theoretical perspective, the interpolating procedure takes place in two
 parts: the first is an estimate of the linear coefficients of a spline function
 is derived from the observation points using a least squares regression; the
@@ -63,8 +63,8 @@
 If output is a vector points map and a "<b><i>sparse=</i></b>" vector points map
 is not specified, the output vector map will contain points at the same
 locations as observation points in the input map, but the values of the output
-points are interpolated values. If a "<b><i>sparse=</i></b>" vector points map
-is specified, the output vector map will contain points at the same locations as
+points are interpolated values. If instead a "<b><i>sparse=</i></b>" vector points
+map is specified, the output vector map will contain points at the same locations as
 the sparse vector map points, and values will be those of the interpolated
 raster surface at those points.
 
@@ -73,7 +73,8 @@
 the optimal <b><i>lambda_i</i></b> value that produces an interpolation that
 best fits the original observation data. The more points used for
 cross-validation, the longer the time needed for computation. Empirical testing
-indicates a threshold of a maximum of 100 points is recommended. The
+indicates a threshold of a maximum of 100 points is recommended. Note that cross
+validation can run very slowly if more than 100 observations are used. The
 cross-validation output reports <i>mean</i> and <i>rms</i> of the residuals from
 the true point value and the estimated from the interpolation for a fixed series
 of <b><i>lambda_i</i></b> values. No vector nor raster output will be created