[gdal-dev] Combine aerial images

[Frank Broniewski]

Am 2012-10-14 11:43, schrieb Jukka Rahkonen:
> Frank Broniewski <brfr <at> metrico.lu> writes:
>
>>
>> Hi,
>>
>> I have a directory with appr. 2800 aerial images, each 1kmx1km. I'm
>> using this source for a Mapserver WMS layer. Unfortunately the amount of
>> data to process is way too much for a Mapserver WMS service.
>>
>> Now I want to create larger overview images where the aerial images are
>> combined together. The route I wanted to was
>>
>> 1) build a VRT from the images
>> 2) use gdal_translate to get a new geotiff with a smaller size (pixel wise)
>>
>> Is this a valid route to go?
>
> Yes it is.
>
> I have configured Mapserver orthoimage layers so that Mapserver does not
> ever need to to open more that about 12-16 original tiff images per one
> screenful of output. We have 12000x12000 pixel images with 0.5 m pixel
> size. Four such side by side makes 48000 pixels and if they are pressed
> to 1000 pixel wide output image the pixel size in output is roughly 25 m.
> Therefore I have prepared resampled layer with 25 m pixel size which
> is used for small scale output.
>
> Prepare new set of images, each covering 50x50 kilometers or more
> with 50 times bigger pixels than the originals. Create scale
> dependent GROUP layer for Mapserver and you should get good speed.
> Naturally you must run gdaladdo for the resampled images and perhaps
> make one more re-resampled set if your coverage is very big.
>
> -Jukka Rahkonen-
>
>>
>> Many thanks,
>>
>> Frank
>
>
>
>
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Hi Jukka,

thanks for your answer. This is what I wanted to hear :-)
My whole area is not larger than 83km x 58km or 166.000 x 116.000 Pixel, 
so its not as big as yours. Your numbers are really helpful, thanks 
again. This should get me going ...

Frank



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