[gdal-dev] need help in arcinfo binary grid format

[Matt Wilkie]

Hi Chandra,

 > This is Chandra Shekhar Tripathi, writing a reader for Arc/Info Binary
 > Grid.We need a little help on this.

Are you aware of the existing gdal aigrd reader?
http://home.gdal.org/projects/aigrid/index.html

cheers,

matt wilkie
--------------------------------------------
Geographic Information,
Information Management and Technology,
Yukon Department of Environment
10 Burns Road * Whitehorse, Yukon * Y1A 4Y9
867-667-8133 Tel * 867-393-7003 Fax
http://environmentyukon.gov.yk.ca/geomatics/
--------------------------------------------


cstripathi wrote:
> Hi All,
> 
> I will explain what I have understood after read the specification ,
> please correct me if I am wrong somewhere.
> In ArcInfo format, entire region is divided into a few number of grids
> and
> each grid is further divided into tiles. Number of tiles in the grid
> can
> be found out by reading fields in hdr.adf  and boundry of grid or
> value of LLX,LLY,URX,URY can  be found out by
> reading fieldes in dblbnd.hdr.
> now after reading all file found out all these value
> 
> 
> After read that hdr.adf file I got this value
> 
> 
> According to specification
> value
> 
> 
> 
> Hcelltype
> 1
> 
> Magic                                                  grid 1.2 /
> 00
> 
> PixelSizeX
> 0.08333
> 
> PixelSizeY
> 0.08333
> 
> TilesPerRow
> 8
> 
> TilesPerColumn
> 512
> 
> TileXSize
> 256
> 
> TileYSize
> 4
> 
> Xref                                                     -58.911352
> 
> Yref                                                     -278.079399
> 
> 
> 
> After read that dblbnd.adf file you got this value
> 
> 
> According to specification
> value
> 
> 
> 
> D_LLX
> 24.
> 
> D_LLY
> -27
> 
> D_URX
> 30
> 
> D_URY
> -22
> 
> now put all value in to spacification
> grid devide in to number of tile=8*512
> & each tile devide into number of block=256*4
> mean each tile contain 1024 cells.& difference  between one cell to
> another cell is 0.08333 according to the geting value
> 
> so   number of collumn in tile*number of block in each tile*pixelsize
> X  =  8 * 256 * 0.08333  =  170
> 
> but if we check with diffreence between ( 30-24 ) then it is only 6
> 
> so where i am wrong or please help me.also explain me how to devide
> grid into tile & tile into block in equal portion
> 
> plz help me
> 
> 
> 
> Thanks
> -Tripathi
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