[mapserver-users] How to tile a large TIF image?

Fri Apr 18 09:07:50 EDT 2008

Sounds like a problem with your gdal install - I'm running a mac also  
and have no problems.  I recommend going back to the kyngchaos site  
and downloading the latest GDAL and installing it.

Cheers

Paul

On 18-Apr-08, at 9:02 AM, Stefan Schwarzer wrote:
> Thanks a lot for these details. That should be added to the existing  
> documents!
>
> But unfortunately I still get a "Segmentation fault" message...
>
> Stef
>
>> Stefan,
>>
>> I don't think you can specify 10'', you need something in pixels.   
>> But the command is also probably not what you really need to do.
>>
>> More likely, you should be doing the following:
>>
>> gdal_translate -co "TILED=YES" gebco/bathymetry.tif gebco/ 
>> bathmetry_tiled.tif
>>
>> This will create a single tif file that has an internal block size  
>> of 256x256 - you can think of this as having broken your tif up  
>> into 256x256 tiles but keeps them all within the same file.  This  
>> is equivalent to breaking the tif up into individual files,  
>> creating a shapefile that has rectangles for each individual files'  
>> extent, and using that as a tile index in mapserver.
>>
>> Next, you want to do this:
>>
>> gdaladdo gebco/bathymetry.tif 2 4 6 8 16
>>
>> this will pre-compute smaller versions of the tif image called  
>> overviews at 1/2, 1/4 1/6 1/8 and 1/16 of the original size of the  
>> tif - this makes it much more efficient for gdal to return exactly  
>> what mapserver is asking for at any given scale.  Depending on the  
>> range of scales that you need to display your raster image at, you  
>> can add more overview levels (or take some away).
>>
>> With this two commands, you can make your rasters much more  
>> efficient for mapserver and probably avoid the need to split them  
>> up into many files.
>>
>> It does make the file somewhat larger.  If you are working with  
>> very large files ( > 4GB ) then you may run into some problems with  
>> tiff and may need to investigate another format or a compressed  
>> format like ECW or MrSID (both requiring commercial licenses I  
>> believe).
>>
>> There are also some built in compression schemes for tiffs in gdal  
>> which you can apply when running gdal_translate (see http://www.gdal.org/frmt_gtiff.html 
>>  for creation options), for instance:
>>
>> gdal_translate -co "TILED=YES" -co "COMPRESS=JPEG" -co  
>> "JPEG_QUALITY=80" gebco/bathymetry.tif gebco/bathmetry_tiled.tif
>>
>> would compress the tif using JPEG compression (lossy) set to 80%  
>> (low compression, small loss).
>>
>> Cheers
>>
>> Paul
>>
>>
>>
>> On 18-Apr-08, at 5:47 AM, Stefan Schwarzer wrote:
>>> Thanks for the info.
>>>
>>> Did it like this:
>>>
>>> Library/Frameworks/GDAL.framework/Versions/1.5/Programs/ 
>>> gdal_translate -outsize 10'' 10'' -co TILED=YES gebco/ 
>>> bathymetry.tif gebco/bathymetry_tiled.tif
>>>
>>> But get the message: "Segmentation fault"
>>>
>>> Anything that I did wrong? Or should do differently?
>>>
>>> Thanks for a hint,
>>>
>>> Stef
>>>
>>>> Hi,
>>>>
>>>> Gdal_translate program has options for you:
>>>>
>>>> c:\FWTools>gdal_translate
>>>> Usage: gdal_translate [--help-general]
>>>>      [-ot {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/
>>>>            CInt16/CInt32/CFloat32/CFloat64}] [-strict]
>>>>      [-of format] [-b band] [-outsize xsize[%] ysize[%]]
>>>>      [-scale [src_min src_max [dst_min dst_max]]]
>>>>      [-srcwin xoff yoff xsize ysize] [-projwin ulx uly lrx lry]
>>>>      [-a_srs srs_def] [-a_ullr ulx uly lrx lry] [-a_nodata value]
>>>>      [-gcp pixel line easting northing [elevation]]*
>>>>      [-mo "META-TAG=VALUE"]* [-quiet] [-sds]
>>>>      [-co "NAME=VALUE"]*
>>>>      src_dataset dst_dataset
>>>>
>>>> By playing with -srcwin or possibly with -outsize and -projwin  
>>>> you should be able to split your image as you wish.  Read more from
>>>> http://gdal.org/gdal_translate.html
>>>>
>>>> -Jukka Rahkonen-
>>>>
>>>>
>>>>
>>>> Lähettäjä: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org 
>>>> ] Puolesta Stefan Schwarzer
>>>> Lähetetty: 18. huhtikuuta 2008 12:05
>>>> Vastaanottaja: mapserver-users at lists.osgeo.org
>>>> Aihe: [mapserver-users] How to tile a large TIF image?
>>>>
>>>> Hi there,
>>>>
>>>> I would like to use instead of single large tif image smaller  
>>>> tiles. Although I am well aware of mapserver's and gdal's  
>>>> possibilities to create the shapes for it, I first need to  
>>>> "split" the large tif into 20 or 50 or 100 tiles.
>>>>
>>>> Can anyone give me a hint with what kind of software this is  
>>>> possible?
>>>>
>>>> There is an ArcGIS script, but it doesn't work on my machine ( http://arcscripts.esri.com/details.asp?dbid=13978 
>>>>  ).
>>>>
>>>> Thanks for any hints,
>>>>
>>>> Stef
>>>>
>>>> ____________________________________________________________________
>>>>
>>>> Stefan Schwarzer
>>>>
>>>> Lean Back and Relax - Enjoy some Nature Photography
>>>> http://photoblog.la-famille-schwarzer.de
>>>>
>>>> Appetite for Global Data? UNEP GEO Data Portal:
>>>> http://geodata.grid.unep.ch
>>>> ____________________________________________________________________
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
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>>
>>
>> __________________________________________
>>
>>  Paul Spencer
>>  Chief Technology Officer
>>  DM Solutions Group Inc
>>  http://www.dmsolutions.ca/
>

__________________________________________

    Paul Spencer
    Chief Technology Officer
    DM Solutions Group Inc
    http://www.dmsolutions.ca/