v.transform: update manual

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@55253 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.transform/v.transform.html

@@ -18,25 +18,13 @@ map. In this case vector objects can be transformed with different
 parameters based on their category number. If the parameter cannot be
 fetched from the table, default value is used instead.<p>
 
-<h3>Affine Transformation Matrix</h3>
-The affine transfomation matrix can optionally be printed with the '-m'
-flag. The format of the matrix is:
-<div class="code" style="width:30%;"><pre>
-| x_offset a b |
-| y_offset d e |
-</pre></div>
-
-This format can be used in the <a href="http://postgis.refractions.net/docs/ch06.html#id2904406">Affine() function of PostGIS</a>
-[Affine(geom, a, b, d, e, xoff, yoff)], or directly compared to the
-output of a similar operation performed in R.
-
 <h2>EXAMPLE</h2>
 
 <h3>DXF/DWG drawings</h3>
 
 <p>Most DXF/DWG drawings are done within XY coordinate space. To transform 
 them to a national grid, we can use <em>v.transform</em> together with 
-<em>v.rectify</em> and a first-order 4 point transformation.
+<em>v.rectify</em> and a first-order transformation.
 
 <div class="code"><pre>
 v.transform -t in=watertowerXY out=watertower_z zscale=0.04 zshift=1320
@@ -48,12 +36,11 @@ v.rectify in=watertower_z out=watertowerUTM points=wt.points order=1
 Spearfish example with manual table editing for vertical shift:
 
 <div class="code"><pre>
-# create table containing transformation parameters:
-echo "create table archsites_t (cat int, zs double)" | db.execute
-# insert transformation parameters for category 1:
-echo "insert into archsites_t values (1, 1000)" | db.execute
-# insert transformation parameters for category 2 (and so forth):
-echo "insert into archsites_t values (2, 2000)" | db.execute
+# work on own map copy:
+g.copy vect=archsites@PERMANENT,myarchsites
+# add new 'zs' column to later store height of each site:
+v.db.addcolumn myarchsites col="zs double precision"
+v.db.update myarchsites layer=1 column=zs value="cat * 1000"
 
 # perform z transformation:
 v.transform -t input=archsites output=myarchsites3d column="zshift:zs" table="archsites_t"
@@ -79,7 +66,7 @@ v.what.rast myarchsites rast=elevation.10m col=zs
 v.db.select myarchsites
 
 # perform transformation to 3D
-v.transform -t myarchsites output=myarchsites3d column="zshift:zs" table=myarchsites
+v.transform -t myarchsites output=myarchsites3d column="zshift:zs" layer=1
 # drop table containing transformation parameters
 v.db.dropcolumn myarchsites3d col=zs
 </pre></div>