Mapgen / sites / coordinates

[Jill Schuler]

%%%From: nra at cix.compulink.co.uk (N R A  )
%%%
%%%(i) can I plot sites with their reference cf. the way I've done it using 
%%%'ps.map' ?
%%%I've tried the 'make.sitefile' but that seems to create the site file - I 
%%%can't see any equivalent to 'make.line', etc.
%%%

(1)
Use the make.symbol and make.label commands together.  The command actually
calls the sites.to.geo command to create a georeferenced file under the 
sites_geo directory.  The contents are: Long\tLat\tDescription

%%%(ii) coordinate system. I've tried the 'make.grid' but that draw lat. & 
%%%long. - being from the UK, I'd rather use the OS National Grid Reference 
%%%system. I'm not sure what projection it is (if any - I thought it was a 
%%%flat easting/northing grid with its 0,0 point just to the SW of the 
%%%Sicily Isles). 

(2)
The make.grid command (USGS grid command) only produces a geographic grid.
You can work around this using GRASS.

Use the v.mkgrid command to build a utm grid file showing your area.
Bring the grid vector file into mapgen using make.line.
Attach labels to the grid using the make.text command.

I have automated this procedure in the 4.13 Interface software for soil
map finishing.  The software is designed to generate a 7.5 x 7.5 quad area
at most.  However, the procedure could be expanded. The script is called
process.utm. It is designed to generate ticks and labels in the margin area
of the map.

%%%Is there some way to either persuade Mapgen to plot based on the 
%%%coordinates of the data - it seems to convert them somehow into lat. & 
%%%long. but shows Manchester area as being somewhere near the equator (3 
%%%degrees lat.) in the Pacific (160 degrees W long.) ??
%%%Or what projection should I use - I'm no geographer - the projection is 
%%%currently 'UTM' (Universal Transverse Mercator ??) and something called 
%%%'Walsbeck ??'

(3)
If you build your geographic grid in mapgen and the grid notation is not
correct, then your original GRASS data is not defined correctly in the
PROJ_INFO file and WIND file. 

Jill


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#  # #### #### ####      ######  #### ##### Jill R. Schuler
#  # #    #  # #  #      #      #     #     USDA 
#  # #### #  # #### ### ####   #     ####   Soil Conservation Service
#  #    # #  # #  #        #  #         #   National Cartography and 
#  #    # #  # #  #       #  #         #    GIS Center
#### #### #### #  #   ####  ###### ####     P.O. Box 6567 
				            Ft. Worth, TX 76115
e-mail: jschuler at ncg.scs.ag.gov             Phone: (817) 334-5559 x3086

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