Polar reprojection (again)

Ed McNierney ed at TOPOZONE.COM
Thu Feb 16 13:06:55 PST 2006


What is the file format and geographic extent of the raster image you're
trying to reproject?  Raster data in "lat/lon" projection (EPSG:4326) in
polar regions is rather badly distorted if not undefined or infinite in
extent.

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Christopher Condit
Sent: Thursday, February 16, 2006 3:44 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] Polar reprojection (again)

All my data is epsg:4326

Each layer has:

PROJECTION
  "init=epsg:4326"
END

I want proj.4 to re-project this on the fly to a polar view, but it only
works for vector data.


>
>What does the PROJECTION of your RASTER LAYER look like?  It needs to
match
>whatever PROJECTION your raster data is in.

>MAP
>  PROJECTION
>    "proj=laea"
>    "lat_0=-90"
>  END
>  LAYER
>    TYPE RASTER
>    PROJECTION
>      ???
>    END
>  END
>END

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Charlton Purvis
Sent: Thursday, February 16, 2006 12:18 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] Polar reprojection (again)

> Under certain application conditions, I need to re-project the map
into a
> polar view.  To do this I change projection string to
> 
> PROJECTION
> 
> "proj=laea"
> 
> "lat_0=-90"
> 
> END
> 
> This works very well for all of my vector data, but none of my raster
data
> appears.  The raster data is in AAI/Grid format.  Will this raster
format
> not re-project?  Should I use a different projection string?



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