[GRASSLIST:3410] How do I annotate DRG topomaps (geo-referenced tiff files) ?

Don Harter harter_d at bellsouth.net
Thu May 13 23:03:38 EDT 2004

I have some USGS DRG topographic maps that I downloaded.  I want to 
create a raster that has vecotr and/or site data plotted on the 
topographic map.  Then I will export the raster to create another DRG 
topographic map that has my data plotted on it.  I am wondering how to 
do that.  One approach would be to display the raster data, vector data 
and then the site data and labels.  Then use the png driver.  That seems 
to be only suitable for a small area not a whole 7.5" topo map.  The 
other approach is to use the cell driver.  That generates a file but it 
is not geo-referenced.  If I could modify its region from (x y pixel 
coordinates) back to my NAD27 topo then that might work.  That is not 
too straightforward.

I thought about using mapcal.  I would convert the site data to a raster 
map then I could superimpose that on the topo raster.  That does not 
seem to work becasue there doesn't appear to be a feature to convert 
site labels to raster.

What would work out best is  if I could just reference my whole region 
in a display where I have already plotted the vector and site data on 
top of the raster, and create a raster layer of plotted data.  I could 
then export this layer to a geo-referenced tiff.  Is there any way that 
I could reference the displayed cells with site data on it so that I 
could use mapcalc to create another raster layer? 

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