[gdal-dev] gdalwarp - Clip raster using mask

[Alisson Barbosa]

Hi,

Thanks for the suggestions. I had to ​​buffer the mask. After, I clipped
the raster with the new mask. Worked for me!

Thank you very much!

2012/11/22 Peter Halls <p.halls at york.ac.uk>

> Alisson,
>
>     the advice I give my students in such a circumstance is to buffer the
> boundary by either one half of the pixel size or by the pixel size.  This
> has the effect of increasing the mask to include all cells along the
> boundary and gain a closer equivalent of a vector clip.
>
>     For another discussion of the issues, see Burrough, P.A., and
> McDonnell, Rachael A., 1998, Principles of Geographic Information Systems,
> Oxford: OUP.
>
> Best wishes,
>
> Peter
>
>
> On 22 November 2012 14:02, Joaquim Luis <jluis at ualg.pt> wrote:
>
>>  Alisson,
>>
>> It's not so easy to follow what is "desired" and "not-desired". For an
>> excellent discussion of the details involved in such operations see
>>
>> http://blogs.mathworks.com/steve/2006/12/22/poly2mask-and-roipoly-part-3/
>>
>> As a solution for your 'wish-behavior'  case maybe what you can do is to
>> previously expand your polygon with a buffer of half cell width.
>>
>> Joaquim
>>
>>  Hi friends,
>>
>> By using gdalwarp to clip a raster with a mask (shape), I get a new
>> raster of smaller size, which is the boundary of the polygon shape (mask).
>> However, the pixels do not pass the polygon. I would like to pass the
>> pixels just a little of the polygon mask.
>>
>> For clarity, I send two pictures of what I desire and not desire:
>> http://postimage.org/image/hlrc3911z/
>> http://postimage.org/image/4vn3q5t3r/
>>
>>  The used command is: gdalwarp -dstnodata 0 -q -cutline
>> C:/Users/Hugo/Final.shp -crop_to_cutline -of GTiff
>> C:/Users/Hugo/Elevation-DEM-CLIPPED.img
>> C:/Users/Hugo/Elevation-DEM-CLIPPED.img
>>
>> Can you help me?
>>
>> Best Regards,
>>  --
>> Alisson Barbosa
>> Systems Analyst - FUNCEME
>> M.Sc. in Computer Science - MACC
>> Graduate in Computer Science  - UECE
>>
>>
>>
>>
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>
>
>
> --
>
> ----------------------------------------------------------------------------------------------------------------
> Peter J Halls, GIS Advisor & Team Leader Applications Support and
> Training,
>                Information Directorate, University of York
> Telephone: 01904 323806     Fax: 01904 323740
> Snail mail: Harry Fairhurst Building, University of York,
>                 Heslington, York YO10 5DD
> This message has the status of a private and personal communication
>
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-- 
Alisson Barbosa
Systems Analyst - FUNCEME
M.Sc. in Computer Science - MACC
Graduate in Computer Science  - UECE
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