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

[cstripathi]

Hi All,

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