[Mapserver-users] mapscript and float32 geotiffs

Thu Jun 10 07:59:54 PDT 2004

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Sean Gillies wrote:

> Hi John,
>
> The Python MapScript maintainer (me) and the GDAL guru (Frank)
> are both away from work at the users meeting.  I don't have
> the resources to test, but I do see several things right away.
>
> Here is 4.2 code that should work.  Note the differences
>
>     # format name should be passed as an arg to factory
>     new_format = mapscript.outputFormatObj('GDAL/GTiff', 'fgtiff')
>     new_format.imagemode = mapscript.MS_IMAGEMODE_FLOAT32
>
>     # Everything else is OK, no need to set mimetype or extension
>
>     # Insert into map.
>     your_map.appendOutputFormat(new_format)
>
>     # Activate
>     your_map.setImageType('fgtiff')
>
> I can't help but make a style suggestion -- mapscript.mapObj is
> a class.  If you name instances of this class mapObj as well, you
> will eventually run into trouble right?  Or maybe you are using
> the experimental next generation API with 'Map', 'Layer', etc, in
> which case carry on. :)
>
> Back to follow up on Monday.
> cheers,
> Sean
>
> -- 
> Sean Gillies
> sgillies at frii dot com
> http://users.frii.com/sgillies
>

Hi Sean,

Thanks for the prompt reply. Certainly your suggestion has helped me 
tidy up that part of my code which I was never very happy with. However, 
the segmentation fault remains. I have traced it to the msImageInitGD 
function where it tries to execute the line:

tpixels = image->img.gd->tpixels[line];

The problem being is that image->img.gd->tpixels is NULL and hence 
indexing it creates the segfault. I'm afraid that I don't know enough 
about the internals of Mapserver to work out why it is zero in this case.

Regards,

- John

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Sean Gillies wrote:<br>
<blockquote cite="mid0EFB4769-BAE2-11D8-9095-000D9329D732 at frii.com"
 type="cite">Hi John,
  <br>
  <br>
The Python MapScript maintainer (me) and the GDAL guru (Frank)
  <br>
are both away from work at the users meeting.  I don't have
  <br>
the resources to test, but I do see several things right away.
  <br>
  <br>
Here is 4.2 code that should work.  Note the differences
  <br>
  <br>
    # format name should be passed as an arg to factory
  <br>
    new_format = mapscript.outputFormatObj('GDAL/GTiff', 'fgtiff')
  <br>
    new_format.imagemode = mapscript.MS_IMAGEMODE_FLOAT32
  <br>
  <br>
    # Everything else is OK, no need to set mimetype or extension
  <br>
  <br>
    # Insert into map.
  <br>
    your_map.appendOutputFormat(new_format)
  <br>
  <br>
    # Activate
  <br>
    your_map.setImageType('fgtiff')
  <br>
  <br>
I can't help but make a style suggestion -- mapscript.mapObj is
  <br>
a class.  If you name instances of this class mapObj as well, you
  <br>
will eventually run into trouble right?  Or maybe you are using
  <br>
the experimental next generation API with 'Map', 'Layer', etc, in
  <br>
which case carry on. :)
  <br>
  <br>
Back to follow up on Monday.
  <br>
cheers,
  <br>
Sean
  <br>
  <br>
--
  <br>
Sean Gillies
  <br>
sgillies at frii dot com
  <br>
<a class="moz-txt-link-freetext" href="http://users.frii.com/sgillies">http://users.frii.com/sgillies</a>
  <br>
  <br>
</blockquote>
<br>
Hi Sean,<br>
<br>
Thanks for the prompt reply. Certainly your suggestion has helped me
tidy up that part of my code which I was never very happy with.
However, the segmentation fault remains. I have traced it to the
msImageInitGD function where it tries to execute the line:<br>
<br>
<small><tt>tpixels = image->img.gd->tpixels[line];<br>
</tt></small><br>
The problem being is that <small><tt>image->img.gd->tpixels</tt>
<big>is NULL and hence indexing it creates the segfault. I'm afraid
that I don't know enough about the internals of Mapserver to work out
why it is zero in this case.<br>
<br>
Regards,<br>
<br>
- John<br>
<br>
</big></small>
<pre class="moz-signature" cols="72">-- 
Website: <a class="moz-txt-link-abbreviated" href="http://www.pml.ac.uk">www.pml.ac.uk</a>
Registered Charity No. 1091222
Company No. 4178503
-------------------------------------------------------------------
This e-mail, its content and any file attachments are confidential.
If you have received this e-mail in error please do not copy,
disclose it to any third party or use the contents or attachments
in any way. Please notify the sender by replying to this e-mail or
e-mail <a class="moz-txt-link-abbreviated" href="mailto:forinfo at pml.ac.uk">forinfo at pml.ac.uk</a> and then delete the email without making
any copies or using it in any other way.

The content of this message may contain personal views which are
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