gridding rules for DEMs
[globe gridding rules]


Functions

bool surfit::dem (const char *dem_name_or_position="0")
bool surfit::dem_add (REAL weight, const char *dem_name_or_position="0")

Function Documentation

bool dem (  const char *  dem_name_or_position = "0"  ) 
 

Tcl syntax:
dem "dem_name_or_position"
Description:
Using this rule the resulting surface approximates DEM in least squares meaning.
Parameters:
dem_name_or_position name of DEM dataset, or DEM position number
Math:
This command adds the following functional to the functional sequence:

\[ \Phi(u_{1,1},\ldots,u_{N,M}) = \sum_{i,j} \left( u_{i,j} - z(x_i, y_j) \right)^2, \]

where (i,j) - indices of the cells, $z(x_i, y_j)$ - DEM value for the (i,j) cell.

Examples:
dem.tcl.

bool dem_add (  REAL  weight,
const char *  dem_name_or_position = "0"
) 
 

Tcl syntax:
dem_add weight "dem_name_or_position"
Description:
This function modifies previous (modifiable) rule by adding the dem rule with some weight.
Parameters:
weight informational weight for this rule
dem_name_or_position name of DEM dataset, or DEM position number
Math:
This command modifies previous functional $ \Phi_0 $ by adding $ \Phi_1 $:

\[ \Phi(u_{1,1},\ldots,u_{N,M}) = \Phi_0(u_{1,1},\ldots,u_{N,M}) + w\Phi_1(u_{1,1},\ldots,u_{N,M}), \]

where $ w $ - informational weight,

\[ \Phi_1(u_{1,1},\ldots,u_{N,M}) = \sum_{i,j} \left( u_{i,j} - z(x_i, y_j) \right)^2, \]

where (i,j) - indices of the cells, $z(x_i, y_j)$ - DEM value for the (i,j) cell.

Examples:
dem_add.tcl.


surfit: open source gridding and contouring software.