[GRASS-user] Reprojection help
rchirgwin at ozemail.com.au
Sat Aug 11 03:59:27 EDT 2007
Vincent BAIN wrote:
> Hello Richard,
> don't know if it can help, but for me it works, from conformal conic
> Lambert to rgf93 (the official geographic coord system in France,
> compliant with wgs84).
> Could you send us the proj information from each of your locations, and
> make sure they correspond to your project ?
The XY location was defined using EPSG code 20356 (Australia from
Geosciences). It shows UTM projection, zone 56, AGD84 datum, and
The LCC location was "self-defined" during import - that is, I created a
new location during import. The project info it created is below:
projection: 99 (Lambert Conformal Conic)
ellipsoid: a=6378160 es=0.006694541854587638
The problem is that I don't know what EPSG code the creator of the
mapset I'm trying to import was using!
> I advise you to define the coordinate systems from epsg codes, the best
> way -- i think -- to avoid problems defining the right ellipsoïd, datum,
> and so on...
> And be cautious: the coordinates read from the display are decimal...
<whacks forehead> I suspect you're telling me I should be using
degree-minute-second format in my transformation?
Thanks, I will go back and look at how I can get the projections lined
up ... I might try defining a standard Australian LCC and see if the
import works; then from a standard location to a standard location might
well be easier.
> Bon courage,
> Le samedi 11 août 2007 à 09:32 +1000, Richard Chirgwin a écrit :
>> It's me again ... I suspect I must be stupider than most Grass users
>> because I seem to be hitting the list with questions so often!
>> I have my own maps which are in lat-long format, using Australian
>> I need to analyse some points relative to some centroids supplied in
>> MapInfo format. They import fine, but they're in Lambert Conformal
>> Conical projection.
>> Without being long-winded, my attempts to reproject the LCC location
>> into a lat-long UTM using WGS84 keep failing - the utilities work but
>> the result isn't right.
>> Is there something about LCC projections that make them hard to reproject?
>> grassuser mailing list
>> grassuser at grass.itc.it
More information about the grass-user