tiff files not displaying

[Matthew Perry]

Matt,

On 9/15/05, Matt Garrish <matthew.garrish at sympatico.ca> wrote:
> 
> Is there any way to mix two types of images, (one in decimal degrees and 
> one in metres?), or do I have to convert one or the other? If I do have to 
> convert (bearing in mind I am complete newbie), would gdalwarp be the right 
> tool? And can it be done when the tif file does not contain coordinate 
> system info?
> 

You can convert them up front using gdalwarp but you have to know the 
original projection. Even if the tiff's projection is not internally 
defined, you can set it using the -s_srs option. The -t_srs option is the 
output projection. Having all the datasets in the same coordinate space as 
your mapfile output will be the fastest option, esp for large datasets.

Alternatively you can mix and match coordiante systems by defining a) a 
PROJECTION object for your MAP which determines the output projection and b) 
a PROJECTION object for each LAYER with a projection other than the output 
projection. If you have huge datasets, reprojecting on the fly like this 
will slow you down a bit but you can keep/maintain each dataset in it's 
native coordinate system. 

-- 
Matt Perry
perrygeo at gmail.com
http://www.perrygeo.net
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