Question about gdal2tiles

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jorgearevalo

Question about gdal2tiles

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Hello,

I've a problem with gdal2tiles. I need to create tiles from an image
of 5 GB, more or less. The image has been created rasterizing a
shapefile. The shapefile's original projection was epsg:23028, but I
had to reproject it to epsg:23030 (because I had to cross this
shapefile with other ones in epsg:23030). To reproject, I used this:

ogr2ogr -s_srs epsg:23028 -t_srs epsg:23030 -f "Mapinfo File" dst.mif src.mif


Then, I rasterized the shapefile reprojected.

After this, I execute gdal2tiles, using resampling method 'near', but
it takes a loooooooooong time to complete the process. With other non
reprojected shapefiles (in epsg 23030 originally), the process is much
faster. What am I doing wrong?

Thanks in advance, and best regards

Jorge
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Rahkonen Jukka

Re: Question about gdal2tiles

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Jorge Arévalo <jorge.arevalo <at> gmail.com> writes:

>
> Hello,
>
> I've a problem with gdal2tiles. I need to create tiles from an image
> of 5 GB, more or less. The image has been created rasterizing a
> shapefile. The shapefile's original projection was epsg:23028, but I
> had to reproject it to epsg:23030 (because I had to cross this
> shapefile with other ones in epsg:23030). To reproject, I used this:
>
> ogr2ogr -s_srs epsg:23028 -t_srs epsg:23030 -f "Mapinfo File" dst.mif src.mif
>
> Then, I rasterized the shapefile reprojected.
>
> After this, I execute gdal2tiles, using resampling method 'near', but
> it takes a loooooooooong time to complete the process. With other non
> reprojected shapefiles (in epsg 23030 originally), the process is much
> faster. What am I doing wrong?
>
> Thanks in advance, and best regards

Hi,

Have a look at gdalinfo reports about the slow image and about one of the fast
ones.  Check if there are considerable differences in image sizes in pixels. If
images are about as big then look at the file formats and see if they are
somehow different.

-Jukka Rahkonen-

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jorgearevalo

Re: Re: Question about gdal2tiles

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On Thu, Oct 29, 2009 at 1:12 PM, Jukka Rahkonen
<[hidden email]> wrote:

> Jorge Arévalo <jorge.arevalo <at> gmail.com> writes:
>
>>
>> Hello,
>>
>> I've a problem with gdal2tiles. I need to create tiles from an image
>> of 5 GB, more or less. The image has been created rasterizing a
>> shapefile. The shapefile's original projection was epsg:23028, but I
>> had to reproject it to epsg:23030 (because I had to cross this
>> shapefile with other ones in epsg:23030). To reproject, I used this:
>>
>> ogr2ogr -s_srs epsg:23028 -t_srs epsg:23030 -f "Mapinfo File" dst.mif src.mif
>>
>> Then, I rasterized the shapefile reprojected.
>>
>> After this, I execute gdal2tiles, using resampling method 'near', but
>> it takes a loooooooooong time to complete the process. With other non
>> reprojected shapefiles (in epsg 23030 originally), the process is much
>> faster. What am I doing wrong?
>>
>> Thanks in advance, and best regards
>
> Hi,
>
> Have a look at gdalinfo reports about the slow image and about one of the fast
> ones.  Check if there are considerable differences in image sizes in pixels. If
> images are about as big then look at the file formats and see if they are
> somehow different.
>
> -Jukka Rahkonen-
>
> _______________________________________________
> gdal-dev mailing list
> [hidden email]
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>

Hello,

Sorry, I forgot to answer. Many thanks for your suggestion. I got some
shapefiles with epsg:23028 original projection and everything worked
fine.

I'll look for information about mathematical projections, I think. I
need to know...

Best regards,
Jorge
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