Changeset 67380

Timestamp:

Dec 26, 2015, 4:35:21 AM (9 years ago)

Author:

martinl

Message:

v.what.rast: create a new column if not exists

Location:

grass/trunk/vector/v.what.rast

Files:

• main.c (modified) (3 diffs)
• v.what.rast.html (modified) (3 diffs)

grass/trunk/vector/v.what.rast/main.c

@@ -10 +10 @@
  *  PURPOSE:      Query raster map
  *                
- *  COPYRIGHT:    (C) 2001-2013 by the GRASS Development Team
+ *  COPYRIGHT:    (C) 2001-2015 by the GRASS Development Team
  * 
  *                This program is free software under the GNU General
@@ -39 +39 @@
     int width;
     int row, col;
-    char buf[2000];
+    char buf[DB_SQL_MAX];
     struct
     {
@@ -163 +163 @@
 
     if (!print_flag->answer) {
-        /* Check column type */
         col_type = db_column_Ctype(driver, Fi->table, opt.col->answer);
 
-        if (col_type == -1)
-            G_fatal_error(_("Column <%s> not found"), opt.col->answer);
-
-        if (col_type != DB_C_TYPE_INT && col_type != DB_C_TYPE_DOUBLE)
-            G_fatal_error(_("Column type not supported"));
-
-        if (out_type == CELL_TYPE && col_type == DB_C_TYPE_DOUBLE)
-            G_warning(_("Raster type is integer and column type is float"));
-
-        if (out_type != CELL_TYPE && col_type == DB_C_TYPE_INT)
-            G_warning(_("Raster type is float and column type is integer, some data lost!!"));
+        if (col_type == -1) {
+            /* column doesn't exist, create it */
+            G_important_message(_("Column <%s> not found in the table <%s>. Creating..."),
+                                opt.col->answer, Fi->table);
+            sprintf(buf, "ALTER TABLE \"%s\" ADD COLUMN \"%s\" %s",
+                    Fi->table, opt.col->answer,
+                    out_type == CELL_TYPE ? "INTEGER" : "DOUBLE PRECISION");
+            db_set_string(&stmt, buf);
+            if (db_execute_immediate(driver, &stmt) != DB_OK)
+                G_fatal_error(_("Unable to add column <%s> to table <%s>"),
+                              opt.col->answer, Fi->table);
+        }
+        else {
+            /* check column type */
+            if (col_type != DB_C_TYPE_INT && col_type != DB_C_TYPE_DOUBLE)
+                G_fatal_error(_("Column type not supported"));
+
+            if (out_type == CELL_TYPE && col_type == DB_C_TYPE_DOUBLE)
+                G_warning(_("Raster type is integer and column type is float"));
+
+            if (out_type != CELL_TYPE && col_type == DB_C_TYPE_INT)
+                G_warning(_("Raster type is float and column type is integer, some data lost!!"));
+        }
     }
 

grass/trunk/vector/v.what.rast/v.what.rast.html

@@ -3 +3 @@
 <em>v.what.rast</em> retrieves raster value from a given raster map for each point
 or centroid stored in a given vector map. It can update a <b>column</b> in the linked
-vector attribute table with the retrieved raster cell value or print it. The column type
-needs to be numeric (integer, float, double, ...).
+vector attribute table with the retrieved raster cell value or print it.
+
+<p>The column type needs to be numeric (integer, float, double,
+...). If the column doesn't exist in the vector attribute table than
+the module will create the new column of type correspoding with the
+input raster map.
+
 <p>
 If the <b>-p</b> flag is used, then the attribute table is not updated
-and the results are printed to <tt>stdout</tt>.
+and the results are printed to standard output.
 <p>
 If the <b>-i</b> flag is used, then the value to be uploaded to the database
@@ -13 +18 @@
 distance weighting method (IDW). This is useful for cases when the vector
 point density is much higher than the raster cell size.
-<p>
-Points and centroid with shared category number cannot be processed.
-To solved this, unique categories may be added with <em>v.category</em> in
-a separate layer.
 
 <h2>NOTES</h2>
 
+<p>
+Points and centroid with shared category number cannot be processed.
+To solved this, unique categories may be added
+with <em><a href="v.category.html">v.category</a></em> in a separate
+layer.
+
+<p>
 If multiple points have the same category, the attribute value is set to NULL.
 If the raster value is NULL, then attribute value is set to NULL.
 <p>
 <em>v.what.rast</em> operates on the attribute table. To modify the vector
-geometry instead, use <em>v.drape</em>.
+geometry instead, use <em><a href="v.drape.html">v.drape</a></em>.
 <p>
 Categories and values are output unsorted with the print flag. To sort them
 pipe the output of this module into the UNIX <tt>sort</tt> tool
 (<tt>sort&nbsp;-n</tt>). If you need coordinates, after sorting use
-<em>v.out.ascii</em> and the UNIX <tt>paste</tt> tool
+<em><a href="v.out.ascii.html">v.out.ascii</a></em> and the UNIX <tt>paste</tt> tool
 (<tt>paste&nbsp;-d'|'</tt>). In the case of a NULL result, a "<tt>*</tt>"
 will be printed in lieu of the value.
@@ -58 +66 @@
 g.region raster=elev_state_500m -p
 
-# add new column to existing table
-v.db.addcolumn map=mygeodetic_pts column="height double precision"
+# query raster cells (a new column will be added to existing table)
 v.what.rast map=mygeodetic_pts raster=elev_state_500m column=height