[Gdal-dev] Image Reprojection

[Frank Warmerdam]

Matt Lynch wrote:
> Hi Frank,
> 
> I have succeed in reprojecting an image that was in UTM to latlon now.
> An error message still appears, however the reprojected image appears to
> match up correctly.
> 
> C:\gdal>gdalwarp -t_srs "+proj=latlong +datum=WGS84"
> 002026_0100_000703_l7_08_
> utm21.tif memTest.tif
> ERROR 1: Can't find requested entry point: pj_strerrno
> 
> Creating output file is that 18397P x 11549L.
> :0...10...20...30...40...50...60...70...80...90...100 - done.
> 
> I still have some questions:
> 
> 1.  How do I fix the error message, and is it significant?

Matt,

The error is not significant.  Upgrading to a very recent PROJ.4
(such as 4.4.6 or 4.4.7) should resolve the message.

> 2.  How can I specify a 10TM (see below for spec)?

I think:

+proj=tmerc +lon_0=-115 +k_0=0.9992 +x_0=500000 +datum=NAD27

(or change +datum=NAD27 to +ellps=clrk66 if you have problems.  Older
PROJ.4 libraries don't support datums).

> 3.  What are the memory limits (the image used was 197M)? (you had
> mentioned one reason to use gdalwarptest would remove memory
> restrictions)

The gdalwarp program will attempt to hold the entire source and
destination image in memory.  The gdalwarptest does the image in
chunks to limit memory use.

> 10TM spec
> ---------
> datum = Nad27
> central meridan = -115
> scale factor = 0.9992
> lat of origin = 0
> false E = 500,000
> false N = 0

Good luck,

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