[Gdal-dev] Warp / rotation

Geographic Wizard geowiz at shaw.ca
Tue Aug 19 16:37:14 EDT 2003


The coordinates in the sample are UTMs and the rectangle is a rectangle, just rotated. I guess what I am looking for is a quick and easy way to pull the subimage with a rotation applied, maybe.

These are UTM's, but they really could be any kind of coordinate.
  ----- Original Message ----- 
  From: Ed McNierney 
  To: gdal-dev at remotesensing.org 
  Sent: Tuesday, August 19, 2003 11:10 AM
  Subject: RE: [Gdal-dev] Warp / rotation


  Dear Wizard -

  The problem is that your "rectangle" isn't a rectangle!  You seem to be trying to reproject your image - can you describe the input and output projections you're using?  Those numbers make it look like your input data might be in UTM (but it could certainly be something else), but what is your desired output projection?

      - Ed
  Ed McNierney
  President and Chief Mapmaker
  TopoZone.com / Maps a la carte, Inc.
  73 Princeton Street, Suite 305
  North Chelmsford, MA  01863
  ed at topozone.com
  (978) 251-4242 

    -----Original Message-----
    From: Geographic Wizard [mailto:geowiz at shaw.ca]
    Sent: Tuesday, August 19, 2003 12:58 PM
    To: gdal-dev at remotesensing.org
    Subject: [Gdal-dev] Warp / rotation


    Hi, everybody

    New to GDAL as well as using georeferenced raster images. I am trying to figure out how to do the following, and any help / insight would be greatly appreciated. I have put some numbers together as an example :

    I have an image (tif/jpg/png) 5000 x 5000 that is georef with a world file

    2
    0
    0
    -2
    667500
    5864000

    I would like to pull a sub image of this that is bound by a rectangle

     669273--------------------------- 670898
    5862482--------------------------- 5862538



     669330--------------------------- 670956
    5860859---------------------------5860910


    I would like line # 1 of the sub-image to be along the top boundary of the rectangle, therefore it needs to be rotated by about 2 degrees cw.

    Any help would be appreciated.

    Thanks,
    Steve
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