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

[Patrick Giraudoux]

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
>
>
>
>   

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