Adding a site to a map - amongst other things

charnotw charnotw at helios.aston.ac.uk
Fri Aug 25 08:00:00 EDT 1995


> 
> Hello - 
>         I had wanted to ask 2 questions.
> 
> 1) How does one add a site to a map. I saw a directory called "sites" in the 
>         "spearfish" sample data. I wanted to add sites to the "global" sample
>         data but this directory did not exist there. I have seen routines tha
t
>         allow one to display site -ex: d.sites, d.points, etc. but I have not
 
>         located one that will allow you to add a site to a sitefile - or even
 to
>         create a site file.



s.menu is the principle program for dealing with sites, it allows you to
create or edit a site file using a standard texteditor. ( a site directory
will be created automatically when you first create a site file). Alternativly
you can use v.to.sites if you want to digitise the data using v.digit. The
structure of a site file is very simple, basically a file containing a list
of coordinates and description seperated by a '|' so it is very easy to
create one manually, eg:

easting|northing|description
easting|northing|description
easting|northing|description

> 2) How can one overlay two or more rasters in the display window.-e.g. I 
>         have raster file 1 and raster file 2 and I would like to place 
> raster 2 on 
>         top of raster 1.

d.rast -o raster_name

allows a raster to be displayed without erasing the previous raster(s), they
show through in areas of no data (ie 0's). If there are no area of no-data
of course the raster will be completely overwritten. Alternatively you could
try d.rgb to display three rasters represented respectively by the intensity
of red green and blue, this is most usefull for remote sensed imagery. 


> Thanks in advance
> 
> Casey
> 
> 
> One must note the importance of setting reasonable and achievable goals for
>                     "If you aim for nothing, you'll hit it every time" 
>                                -Theodore Roosevelt
> 

cheers Tom  8-)


Tom Charnock                       O--O
Dept Civil Engineering            (~~~~)
Aston University                 (  __  )
Birmingham B4 7ET UK             /|\  /|\
charnotw at sun.aston.ac.uk







More information about the grass-user mailing list