The data will be exported as a rectangular grid composed of square grid cells. This means that if the kriged data present covers an irregularly shaped sample area, the kriged data will still be exported as a rectangular grid, with no data values present for those cells that fall outside the sample area, as shown below. In addition, although VSP allows rectangular kriged data grid cells, the ESRI grid format supports only square grid cells. The smaller dimension of the kriged cells in VSP will be used as the ESRI grid cell size, so the results may appear distorted when imported into another program.
The first 6 lines of the file describe the dimensions and other properties of the grid. The meaning of the header lines are:
ncols: |
The number of columns in the grid |
nrows: |
The number of rows in the grid |
xllcenter: |
The x coordinate of the center of the grid cell in the lower left corner of the grid |
yllcenter: |
The y coordinate of the center of the grid cell in the lower left corner of the grid |
cellsize: |
The length of one side of the square grid cell |
nodata_value: |
The value used to signify that no data is present for a particular grid cell. Grid cells that fall outside the sample area will have this value, as well as grid cells for which no kriged estimate could be calculated. |
The last lines of the file are the rows of grid values, starting with the upper leftmost value and moving left to right and top to bottom.
Example of kriged data from non-rectangular sample area exported from VSP and imported into ArcMap. 'no_data' values are colored gray.