v.cluster: add image to manual

make simple example primary, show how to display, add see also


git-svn-id: https://svn.osgeo.org/grass/grass/trunk@66136 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.cluster/v.cluster.html

@@ -91,55 +91,113 @@ Analysis of random points for areas in areas of the vector
 <i>urbanarea</i> (North Carolina sample dataset).
 
 <p>
-10000 random points within the areas the vector urbanarea and within the 
-subregion:
+First generate 1000 random points within the areas the vector urbanarea
+and within the subregion, then do clustering and visualize the result:
 
 <div class="code"><pre>
 # pick a subregion of the vector urbanarea
 g.region -p n=272950 s=188330 w=574720 e=703090 res=10
 
-# create clustered points
-v.random output=rand_clust npoints=10000 restrict=urbanarea@PERMANENT
+# create random points in areas
+v.random output=random_points npoints=1000 restrict=urbanarea
 
 # identify clusters
-v.cluster in=rand_clust out=rand_clusters method=dbscan
+v.cluster input=random_points output=clusters_optics method=optics
 
-# create colors for clusters
-v.db.addtable map=rand_clusters layer=2 columns="cat integer,grassrgb varchar(11)"
-v.colors map=rand_clusters layer=2 use=cat color=random rgb_column=grassrgb
+# set random vector color table for the clusters
+v.colors map=clusters_optics layer=2 use=cat color=random
 
-# display with your preferred method
+# display in command line
+d.mon wx0
+
+# note the second layer and transparent (none) color of the circle border
+d.vect map=clusters_optics layer=2 icon=basic/point size=10 color=none
 </pre></div>
 
-<p>
-100 random points for each area in the vector urbanarea and within the 
-subregion:
 
+<center>
+<img src="v_cluster_4_methods.png">
+<p><em>
+    Figure: Four different methods with default settings applied to
+    1000 random points generated in the same way as in the example.
+</em></p>
+</center>
+
+<!--
+g.region -p n=272950 s=188330 w=574720 e=703090 res=10
+v.random output=rand_clust npoints=1000 restrict=urbanarea
+
+v.cluster in=rand_clust out=rand_clusters_dbscan method=dbscan
+v.colors map=rand_clusters_dbscan layer=2 use=cat color=random
+
+v.cluster in=rand_clust out=rand_clusters_dbscan2 method=dbscan2
+v.colors map=rand_clusters_dbscan2 layer=2 use=cat color=random
+
+v.cluster in=rand_clust out=rand_clusters_density method=density
+v.colors map=rand_clusters_density layer=2 use=cat color=random
+
+v.cluster in=rand_clust out=rand_clusters_optics2 method=optics2
+v.colors map=rand_clusters_optics2 layer=2 use=cat color=random
+
+v.cluster in=rand_clust out=rand_clusters_optics method=optics
+v.colors map=rand_clusters_optics layer=2 use=cat color=random
+
+# seems we have to remove first to avoid drawing into an old image
+rm v_cluster_4_methods.png
+
+d.mon cairo out=v_cluster_4_methods.png
+
+# the font doesn't work
+d.font "LiberationSans-Regular"
+
+d.frame frame=dbscan at=50,100,0,50 -c
+d.vect map=rand_clusters_dbscan layer=2 icon=basic/point size=10 color=none
+d.text text="dbscan" at=5,5 size=10 bgcolor=white
+
+d.frame frame=optics at=50,100,50,100 -c
+d.vect map=rand_clusters_optics layer=2 icon=basic/point size=10 color=none
+d.text text="optics" at=5,5 size=10 bgcolor=white
+
+d.frame frame=density at=0,50,0,50 -c
+d.vect map=rand_clusters_density layer=2 icon=basic/point size=10 color=none
+d.text text="density" at=5,5 size=10 bgcolor=white
+
+d.frame frame=optics2 at=0,50,50,100 -c
+d.vect map=rand_clusters_optics2 layer=2 icon=basic/point size=10 color=none
+d.text text="optics2" at=5,5 size=10 bgcolor=white
+
+d.mon stop=cairo
+-->
+
+Generate random points for analysis (100 points per area), use different
+method for clustering and visualize using color stored the attribute table.
 <div class="code"><pre>
 # pick a subregion of the vector urbanarea
 g.region -p n=272950 s=188330 w=574720 e=703090 res=10
 
-# create 100 clustered points
-v.random output=rand_clust npoints=100 restrict=urbanarea@PERMANENT -a
+# create clustered points
+v.random output=rand_clust npoints=100 restrict=urbanarea -a
 
 # identify clusters
-v.cluster input=rand_clust output=rand_clusters method=density
+v.cluster in=rand_clust out=rand_clusters method=dbscan
 
 # create colors for clusters
-v.db.addtable map=rand_clusters layer=2 columns="cat integer"
-v.colors map=rand_clusters layer=2 use=cat color=random
+v.db.addtable map=rand_clusters layer=2 columns="cat integer,grassrgb varchar(11)"
+v.colors map=rand_clusters layer=2 use=cat color=random rgb_column=grassrgb
 
 # display with your preferred method
-d.mon wx0
-# show clusters by color
-d.vect rand_clusters layer=2
+# remember to use the second layer and RGB column
+# for example use
+d.vect map=rand_clusters layer=2 color=none rgb_column=grassrgb icon=basic/circle
 </pre></div>
 
 
 <h2>SEE ALSO</h2>
 
 <em>
-<a href="r.clump.html">r.clump</a>
+<a href="r.clump.html">r.clump</a>,
+<a href="v.hull.html">v.hull</a>,
+<a href="v.distance.html">v.distance</a>
 </em>
 
 <h2>AUTHOR</h2>