get part of very large raster

[Bart van den Eijnden]

Hi Ivan,

you can use GDAL to do this:

gdal.maptools.org

More specifically, the gdal_translate utility can clip:

-srcwin xoff yoff xsize ysize:
Selects a subwindow from the source image for copying based on pixel/line
location.

-projwin ulx uly lrx lry:
Selects a subwindow from the source image for copying (like -srcwin) but
with the corners given in georeferenced coordinates.

Best regards,
Bart

> Hi, everybody
>
> I have little problem,
>
>
>
> I have very large raster over 100M, and I have to programming small
> program, that on input get Xmin, Xmax, Ymin, Ymax and return small wedge
> of this large raster.
>
>
>
> My first test was using GD library but problem is that this library  load
> whole raster into memory and its mean, that its take very long time.
>
>
>
> I know (I am developing something on mapserver), that mapserver is doing
> this and very fast and my question is, which library mapserver is using ,
> or  which part of code is processing this ?
>
>
>
>
>
> Thanks very much for your reply
>
> ivan mjartan
>