GIS-Datei-Format

Siehe auch Geodaten.

ESRI GIS-Datei-Formate

ArcInfo (ESRI) ASCII Grid format (.grd)

Refers to a specifc interchange format developed for ARC/INFO rasters in ASCII format. The format consists of a header that specifies the geographic domain and resolution, followed by the actual grid cell values. Usually the file extension is .asc, but recent versions of ESRI software also recognize the extension .grd.

Es können Werte von entweder integer (+/- 2 Milliarden) oder Float (+/- 10E38, 15 Digits) verwaltet werden.

Links:

• http://docs.codehaus.org/display/GEOTOOLS/ArcInfo+ASCII+Grid+format
• http://www.safe.com/support/online-documentation/ReadersWriters/ReadersWriters.htm#esriasciigrid_-_esri_ascii_grid_reader_writer.htm

Description:

The numbers of rows and columns are defined in the Grid NDX, NDY fields of the corresponding windows.

This format is used to export distributions in a ArcInfo compatible ASCII grid format. Cell Origin 0 or 0.5.

Syntax:

 ncols [number of columns]
 nrows [number of rows]
 xllcorner [x coordinate of lower left corner]
 yllcorner [y coordinate of lower left corner]
 cellsize  [cell size in meters]
 nodata_value [value which will be used if no data in grid cell; default is -9999]
 row 1 
 row 2
 ...

.tfw ESRI world file

The ESRI World format stores the image-coordinates-to-world-coordinates transformation data resulting from the georeferencing process executed in the Map Assistant. The resulting file contains the transformation factors A to F defining the registering of the image in accordance with the equation below:

  1. x' = A x + B y + C

  2. y' = D x + E y + F

with x,y = Image coordinates

    x',y'= Real world coordinates
    A = x-scale
    B,D = rotation terms
    C,F = translation terms
    E = y-scale (negative)
    

Example for a .tfw file:

   4.23214625853148 - A
   0.00000000000000 - D
   0.00000000000000 - B
  -4.23214625853148 - E
   3404018.70881921 - C
   5819863.55539414 - F

Weblinks

• GIS-Datei-Format auf Wikipedia