[Gdal-dev] Image Reprojection

[Matt Lynch]

Hi Frank,

That did the trick!  Over the next few days I will work on a usage
tutorial for gdalwarp and submit.  That way you don't have to answer the
same questions repetively.

Thanks again,

Matt

-----Original Message-----
From: gdal-dev-admin at remotesensing.org
[mailto:gdal-dev-admin at remotesensing.org] On Behalf Of Frank Warmerdam
Sent: Saturday, April 05, 2003 1:41 AM
To: gdal-dev at remotesensing.org
Subject: Re: [Gdal-dev] Image Reprojection


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,

-- 
---------------------------------------+--------------------------------
---------------------------------------+------
I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent


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