Changeset 60247 for grass/trunk/raster/r.in.lidar

Timestamp:

May 15, 2014, 3:21:58 AM (10 years ago)

Author:

neteler

Message:

r.in.lidar: return filter added (from v.in.lidar)

Location:

grass/trunk/raster/r.in.lidar

Files:

• main.c (modified) (9 diffs)
• r.in.lidar.html (modified) (1 diff)

grass/trunk/raster/r.in.lidar/main.c

@@ -27 +27 @@
 #include <grass/gprojects.h>
 #include <grass/glocale.h>
+#include <liblas/capi/liblas.h>
 #include "local_proto.h"
 
@@ -40 +41 @@
 struct node *nodes;
 
+#define LAS_ALL 0
+#define LAS_FIRST 1
+#define LAS_LAST 2
+#define LAS_MID 3
 
 int new_node(void)
@@ -139 +144 @@
 
     struct GModule *module;
-    struct Option *input_opt, *output_opt, *percent_opt, *type_opt;
+    struct Option *input_opt, *output_opt, *percent_opt, *type_opt, *filter_opt;
     struct Option *method_opt, *zrange_opt, *zscale_opt;
     struct Option *trim_opt, *pth_opt, *res_opt;
@@ -149 +154 @@
     LASSRSH LAS_srs;
     LASPointH LAS_point;
+    int return_filter;
 
     struct Key_Value *loc_proj_info = NULL, *loc_proj_units = NULL;
@@ -155 +161 @@
     struct Cell_head cellhd, loc_wind;
 
+    unsigned int n_filtered;
 
     G_gisinit(argv[0]);
@@ -237 +244 @@
         _("Output raster resolution");
 
+    filter_opt = G_define_option();
+    filter_opt->key = "filter";
+    filter_opt->type = TYPE_STRING;
+    filter_opt->required = NO;
+    filter_opt->label = _("Only import points of selected return type");
+    filter_opt->description = _("If not specified, all points are imported");
+    filter_opt->options = "first,last,mid";
+
     print_flag = G_define_flag();
     print_flag->key = 'p';
@@ -303 +318 @@
 
         exit(EXIT_SUCCESS);
+    }
+
+    return_filter = LAS_ALL;
+    if (filter_opt->answer) {
+        if (strcmp(filter_opt->answer, "first") == 0)
+            return_filter = LAS_FIRST;
+        else if (strcmp(filter_opt->answer, "last") == 0)
+            return_filter = LAS_LAST;
+        else if (strcmp(filter_opt->answer, "mid") == 0)
+            return_filter = LAS_MID;
+        else
+            G_fatal_error(_("Unknown filter option <%s>"), filter_opt->answer);
     }
 
@@ -322 +349 @@
         /* Does the projection of the current location match the dataset? */
         /* G_get_window seems to be unreliable if the location has been changed */
-        G_get_set_window(&loc_wind);
+        G_get_set_window(&loc_wind); /* TODO: v.in.lidar uses G_get_default_window() */
         /* fetch LOCATION PROJ info */
         if (loc_wind.proj != PROJECTION_XY) {
@@ -736 +763 @@
             y = LASPoint_GetY(LAS_point);
             z = LASPoint_GetZ(LAS_point);
+
+        if (return_filter != LAS_ALL) {
+            int return_no = LASPoint_GetReturnNumber(LAS_point);
+            int n_returns = LASPoint_GetNumberOfReturns(LAS_point);
+            int skipme = 1;
+
+            if (n_returns > 1) {
+
+                switch (return_filter) {
+                case LAS_FIRST:
+                    if (return_no == 1)
+                        skipme = 0;
+                    break;
+                case LAS_LAST:
+                    if (return_no == n_returns)
+                        skipme = 0;
+                    break;
+                case LAS_MID:
+                    if (return_no > 1 && return_no < n_returns)
+                        skipme = 0;
+                    break;
+                }
+            }
+            if (skipme) {
+                n_filtered++;
+                continue;
+            }
+        }
 
             if (y <= pass_south || y > pass_north) {

grass/trunk/raster/r.in.lidar/r.in.lidar.html

@@ -85 +85 @@
 <!-- explained: memory use for regular stats will be based solely on region size,
  but for the aggregate fns it will also depend on the number of data points. (?) -->
-
+<p>
+A LiDAR pulse can have multiple returns. The first return values can be 
+used to obtain a digital surface model (DSM) where e.g. canopy cover is 
+represented. The last return values can be used to obtain a digital 
+terrain model (DTM) where e.g. the forest floor instead of canopy 
+cover is represented. The <b>filter</b> option allows to select one of 
+first, mid, or last returns.
 <p>
 The default map <b>type</b>=<tt>FCELL</tt> is intended as compromise between