GMS:Importing/Exporting GIS Grids

GMS includes an option to import and export grid files from/to either the GRASS or ARC/INFO (ArcView) geographic information systems formats.

Importing

Grids are imported using the Open command in the File menu.

With GRASS and ARC/INFO grid files, the grid and the attributes are saved to a single file. When a grid file is imported, GMS constructs the grid, and then reads in the attribute matrix as a data set.

When a grid in GRASS or ARC/INFO contains multiple attributes (data sets), each attribute is written to a separate grid file. In such cases, it is possible to read in one instance of the grid file to create a grid with a single data set, and then read in the other grids as extra data sets on the first grid. This can be accomplished as follows:

1. Select the Open command from the File menu.
2. Choose either the GRASS or ARC/INFO file filter.
3. Select the grid file.
4. Select the OK button.

At this point, the first grid file is imported resulting in a grid with a single data set. For the additional data sets, steps 1-5 are repeated but now GMS will detect that there is already a 2D grid in memory that matches the grid being imported and will ask whether you want to replace the existing grid, or add the new grid as a data set of the existing grid.

Exporting

Grids can be exported from GMS in the GRASS or ARC/INFO format by right-clicking on the grid in the Project Explorer and selecting the Export menu command. Only grids with equal row heights and equal column widths can be exported. When a grid is exported, the grid and the active data set are written to the GIS file. If multiple data sets are associated with the grid, each data set should be made the active data set and the grid should be exported repeatedly so that each data set is written to a separate grid file.

See also

• 2D Grid Module