The spatial surrogates files contain the spatial allocation factors for all area sources and non-link mobile sources. One file may be used for both area and mobile sources, however, multiple surrogate files may also be used to futher separate and refine the detail of the spatial allocation. The location of these files can be found in Table 8.3, “Spatial Allocation Input File Locations” The format for these files is shown in Table 8.36, “Format for Area and Mobile spatial surrogate files.”.
Table 8.36. Format for Area and Mobile spatial surrogate files.
| Line | Position | Description |
|---|---|---|
| 1 | A | #GRID |
| B | Grid name | |
| C | X origin in units of the projection | |
| D | Y origin in units of the projection | |
| E | X direction cell length in units of the projection | |
| F | Y direction cell length in units of the projection | |
| G | Number of columns | |
| H | Number of rows | |
| I | Number of boundary cells | |
| J |
Projection types:
|
|
| K | Projection units | |
| L | Projection alpha value | |
| M | Projection beta value | |
| N | Projection gamma value | |
| O | X-direction projection center in units of the projection | |
| P | Y-direction projection center in units of the projection | |
| 2+ | A | Spatial surrogates code (area) or county feature/roadway type (mobile) (Integer) (required) |
| B | Country/state/county code (6-digit Integer YSSCCC) (required) | |
| C | Grid column number (Integer) (required) | |
| D | Grid row number (Integer) (required) | |
| E | Spatial surrogate ratio (area) or fraction of county feature in cell (mobile) (Real) (required) |