[GRASS-user] Re: [Proj] trouble transforming corine landcover raster projection Lambert laea to lcc

[Yves Jacolin]

Hi Patrick,

I succeed to import Corine Land Cover inside GRASS wittout problem.

First of all, you need to create correct projection for your location. Both of 
them seems to me incorrecte. Here what I get for my location where I import 
corine Land Cover :
-PROJ_INFO-------------------------------------------------
name       : Lambert Conformal Conic
proj       : lcc
a          : 6378249.2
es         : 0.0068034876
lat_1      : 45.89891888901534
lat_2      : 47.69601444454726
lat_0      : 46.8000000000016
lon_0      : 2.3372291666985
x_0        : 600000
y_0        : 2200000
towgs84    : -168,-60,320,0,0,0,0
no_defs    : defined
-PROJ_UNITS------------------------------------------------
unit       : Meter
units      : Meters
meters     : 1

Which is really different from yours. I imported some other data from other 
data provider as well (town, ...) and it seems correct.

Your projection seems to be WGS84 (not defined so default used) and so you got 
some error (latlong begin -180,-90 to 180,90).

When you create a projection, you can try to use EPSG code (27572 for lambert 
2 et.), use french country as region (bbox). If you use raster data, take 
care of the resolution of your region.

Regards,

Y.
PS : why do you talk about raster for corrine land cover? This is a vector 
file! isn't ?
Le Lundi 26 Mars 2007 18:28, Patrick Giraudoux a écrit :
> Dear Hamish and Yves,
>
> Results OK on one hand and screwed up on the other:
> > In the corineurope location try
> >
> > g.region rast=fc
> >
> >
> > and then go back into your franceLIIe mapset and try again.
>
> has not been conclusive, BUT
>
> > another trick is in your source location (corine) zoom around your map
> > and run v.in.region to make a box, then in Lambert location use v.proj
> > to import the box, then "g.region vect=box" to get the zoom ready for
> > the raster map.
>
> Worked excellent...
>
> So definitely one can go a step further with this improved definition of
> GRASS regions (thanks for the trick, will be most helpful, Hamish),
>
> HOWEVER,
>
> The raster obtained failed to fall into the right coordinate range...
>
> which may well fit with Yves' remark:
> > This not a lambert 2 etendu region. 1 000 000 diffents to the west (I may
> > be wrong)
>
> I am a bit loosing my mind on that. The shapefiles given by BD carto
> have a coordinate range and projections given to be "Lambert II etendu"
> (eg Besancon is 2256000 880000) and corine landcover has Lambert
> Azimutal Equal Area. I have parametrized projections from indications
> given on Corine and IGN notices respectively. To sum up, within the
> Corine Land Cover I have got this region for the Franche-Comte window:
>
> GRASS 6.0.2 (corineurope):~ > g.region -p
> projection: 99 (Lambert Azimuthal Equal Area)
> zone:       0
> datum:      ** unknown (default: WGS84) **
> ellipsoid:  grs80
> north:      2781245
> south:      2571341
> west:       3952172
> east:       4110683
> nsres:      100.00190567
> ewres:      100.00694006
> rows:       2099
> cols:       1585
>
> An acceptable window in for France in Lambert II etendu would be
> north:      2677442
> south:      1620430
> west:       47679
> east:       1197823
>
> When I project from what I believe to be Corine Land Cover to what I
> believe to be Lambert II etendu, I get this region for the Franche-Comte
> region:
>
> GRASS 6.0.2 (franceLambertIIe):~ > g.region -p
> projection: 99 (Lambert Conformal Conic)
> zone:       0
> datum:      ** unknown (default: WGS84) **
> ellipsoid:  clark80
> north:      5781377.23822138
> south:      5575874.90520341
> west:       5197476.01104252
> east:       5391683.44065733
> nsres:      100.00113529
> ewres:      100.00382575
> rows:       2055
> cols:       1942
>
> Which is really crazy...
>
> Any suggestion welcome,
>
> Best regards,
>
> Patrick
>
> Hamish a écrit :
> > Patrick Giraudoux wrote:
> >> GRASS 6.0.2 (franceLIIe):~ > r.proj input=fc location=corineurope
> >> mapset=giraudoux output=fc
> >
> > In the corineurope location try
> >
> > g.region rast=fc
> >
> >
> > and then go back into your franceLIIe mapset and try again.
> >
> >
> > another trick is in your source location (corine) zoom around your map
> > and run v.in.region to make a box, then in Lambert location use v.proj
> > to import the box, then "g.region vect=box" to get the zoom ready for
> > the raster map.
> >
> >
> > good luck,
> > Hamish

-- 
Yves Jacolin
-------------
http://yjacolin.gloobe.org
http://softlibre.gloobe.org