raster representation problems

[Frank Warmerdam]

cfb wrote:
> Hi there, 
> 
> I've some problems with the representation of a raster image (.img). I've
> clasiffied it by its pixels, but when I zoom it I get white areas with no
> data (and if I make the GetFeatureInfo I get: "msQueryByPoint(): Search
> returned no results. No matching record(s) found" in the ms_error file. 
> 
> I've been trying with several processing directives, but it doesn't change
> anything. The image is ok, and I don't know where is the problem... 
> 
> Here it is the layer object of my .map 
> 
> LAYER 
>  TRANSPARENCY ALPHA 

Carla,

What is TRANSPARENCY ALPHA supposed to do?  I'm sure I *should* know this.

>   #PROCESSING "CLOSE_CONNECTION=DEFER" 
>   PROCESSING "DITHER=YES"     
>   #PROCESSING "SCALE_1=1,255" 
>   #PROCESSING "SCALE_2=2,255" 
>   #PROCESSING "SCALE_3=3,255" 
>   #OFFSITE 255 255 255 
>   #PROCESSING "SCALE=AUTO" 
>   #PROCESSING "DITHER=YES" 

When using explicit [pixel] classification, it is inappropriate to use
scaling directives and they might screw stuff up.

>   TOLERANCE 3 
>   TOLERANCEUNITS pixels 
>   DUMP TRUE 
>   OFFSITE 255 255 255 

I don't think OFFSITE is going to work properly in a classification
situation.  You might want to omit this.

However, fundamentally I don't know why you are getting the problem
you get.  I assume the GetFeatureInfo is for a point that should have
data?

You have a template and dump set to true so it seems that all the basic
requirements are in place.

If you can boil your mapfile and data down to something that could be
provided to me along with a particular GetFeatureInfo request that
is failing I could dig into it a bit.  But you need to pass things over
in a form that I can get the problem reproduced easily or I will get
distracted before getting any deeper.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | President OSGeo, http://osgeo.org