[GRASS-SVN] r59991 - grass/branches/releasebranch_6_4/vector/v.buffer2

[svn_grass at osgeo.org]

Author: neteler
Date: 2014-04-30 09:18:23 -0700 (Wed, 30 Apr 2014)
New Revision: 59991

Modified:
   grass/branches/releasebranch_6_4/vector/v.buffer2/description.html
Log:
v.buffer manual: examples cleanup

Modified: grass/branches/releasebranch_6_4/vector/v.buffer2/description.html
===================================================================
--- grass/branches/releasebranch_6_4/vector/v.buffer2/description.html	2014-04-30 15:38:24 UTC (rev 59990)
+++ grass/branches/releasebranch_6_4/vector/v.buffer2/description.html	2014-04-30 16:18:23 UTC (rev 59991)
@@ -8,11 +8,16 @@
 
 <h2>NOTES</h2>
 
+Internal buffers for areas can be generated with negative distance 
+values ("inward buffer" or "negative buffer").
 <!-- Q: True?  A: Sure. if two point buffers overlap and are merged, which
      area's attribute is the one to use in the combined area? -->
 Attributes are not transferred due to potential buffer overlap, which
 cannot be resolved automatically.
 
+<p>
+Buffers for lines and areas are generated using the algorithms from
+the GEOS library.
 
 <h2>EXAMPLES</h2>
 
@@ -33,28 +38,31 @@
 <h3>Circles around input points</h3>
 
 <div class="code"><pre>
-v.buffer input=hospitals output=hospitals_circled type=point distance=1000 
+v.buffer input=hospitals output=hospitals_circled type=point distance=2000 
 </pre></div>
 
+<center>
+<img src="v_buffer_points.png" border="1"><br>
+Buffer of 2000m around the "hospitals" points (map subset, original points
+shown in black, new area centroids in red)
+</center>
+
 <h3>Overlapping circles around input points with attribute transfer</h3>
 
 <div class="code"><pre>
-v.buffer input=hospitals output=circles type=point distance=2000
+# copy map to current mapset (for easier DB linking)
+g.copy vect=hospitals,myhospitals
+v.buffer input=myhospitals output=circles type=point distance=2000
 # change original points to centroids: 
-v.type in=hospitals out=hospital_centroids type=point,centroid 
+v.type in=myhospitals out=hospital_centroids type=point,centroid 
 # patch circles and centroids: 
 v.patch in=hospital_centroids,circles out=circles_db 
 # attach attributes, either use db.copy or link to the original table: 
-v.db.connect map=circles_db table=hospitals layer=1 key=cat driver=dbf \
+v.db.connect map=circles_db table=myhospitals layer=1 key=cat driver=dbf \
      database='$GISDBASE/$LOCATION_NAME/$MAPSET/dbf'
+v.db.select circles_db
 </pre></div>
 
-<center>
-<img src="v_buffer_points.png" border="1"><br>
-Buffer of 2000m around the "hospitals" points (map subset, original points
-shown in black, new area centroids in red)
-</center>
-
 <h3>Buffer around input areas</h3>
 
 <div class="code"><pre>
@@ -67,6 +75,12 @@
 shown in black)
 </center>
 
+<h2>REFERENCE</h2>
+
+<ul>
+<li><a href="http://trac.osgeo.org/geos">GEOS Library</a></li>
+</ul>
+
 <h2>SEE ALSO</h2>
 
 <em>