[GRASS-user] Import, project

[stn]

2010/6/17 Hamish <hamish_b at yahoo.com>

>
> you have to create a GRASS Location for each source map projection, then
> pull them all into the target Location with r.proj or v.proj.
>

Hi Hamish, thanks for the infos.


Here is one thing I can't get into my head.

First there is the problem that I do not know the coordinates and projection
etc of the two files mentioned. Of course I can go to someone with
esri-software and ask him to check that for me.

But in my (apparently very naive) view I this is completely not the point.
If I have to use esri anyway then why bother taking data into grass ??

What I would think is this: If I can find out the projection/coordinates etc
of the shapefile by any manual means then this info MUST BE included in the
shapefile itself. Along with the actual geodata.

More so the import-program within grass cannot import even a single byte
without thorough knowledge of the imported format, but i seems that it can
only read objects but not their coordinate-system.


So: If all the info is already in the shapefile there then why

1) do I have to manually find it by some way outside grass and

2) why doesn't the import-program simply read that info from the file, read
the coordinates and projection from the current location and the call the
appropriate projection-program to reproject the imported file to fit the
current location.

All the infos (proj/coord/bounds/etc) of import and target are there (says
the naive man :-) , the sequence of operations is completely obvious and
always exactly the same and yet everything has to be done manually.

If I want to recode a moviefile to another format I tell the encoder what I
want to have as an output and the encoder then looks by itself what format
the original has. What is different about geodata ?

I don't really mind doing that for one map. But somehow I expect lots more
maps from different sources being added later and each one causing lots of
work. What is it I don't understand here?




 > 3) how to export an ascii/excel/csv-list of every raster-point with a)
> > the corresponding scalar and b) the administrative region and c) the
> > coordinates lat/long of the raster-point
>
> r.out.xyz, or r.to.vect + v.out.ascii
> maybe with some other custom magic along the way.
>

Thanks, that sounds promising. I will try ASAP.




> from the command line GDAL's ogr2ogr and gdalwarp can reproject shapefiles
> and GeoTiffs etc directly.
>

Tried that (on ubuntu) :

user at nb ~ $ gdalwarp file1.shp file1.out
ERROR 4: `file1.shp' not recognised as a supported file format.

and: gdalwrap --formats lists 88 formats including a few from esri, but no
shapefile.


stn
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