MERGE2

 

like GRID MERGE, but 1) accepts a wildcard or list file to specify input grids, 2) reprojects input grids into common projection before merging, 3) supports up to 2401 input grids (in theory), and 4) fills gaps between grids after merging.

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MERGE2 <wildcard | list_file> <out_grid> {prj_source} {gap_width}

 

ARGUMENTS

 

<wildcard | list_file> - the wildcard or ascii file that identifies which grids are to be merged.

 

wildcard - e.g. 'dem*'.

 

list_file - an ascii file that list the input grids, one name per line.

 

<out_grid> - the name for the output grid.

 

{prj_source} - the name of the coverage/grid/file whose projection information defines the projection for the output grid.

 

Each input grid whose projection does not match that of the {prj_source} will be reprojected to match.  (A temporary grid is used; the input grid itself is not modified.)  Reprojection is accomplished using the BILINEAR option and the southwest corner of the input grid is used as the registration point.

 

If {prj_source} is not specified, then all grids are assumed to be in the same projection.

 

{gap_width} - the maximum thichness (in cell widths) of gaps to be filled.

 

The default is 4 cells.

 

Gaps are filled using GRID FOCALMEAN to average the values of the cells neighboring the gaps.

 

 

NOTES

 

MERGE2 runs from the GRID module of ARC/INFO.

 

EXAMPLES

 

1) To display usage:

 

Grid: &run merge2 usage

Usage: MERGE2 <wildcard | list_file> <out_grid> {prj_source} {gap_width}

 

2) An example of merging a whole bunch of DEM grids together to create an output grid in UTM Zone 11 without gaps between quads:

 

Grid: &run merge2 dem* och_dem30 utm11.prj 3