Differences
This shows you the differences between two versions of the page.
| Next revision | Previous revision | ||
|
calc_interaction_potential_map [2011/07/25 15:36] hermann created |
calc_interaction_potential_map [2026/08/28 03:11] (current) hermann Sync from local documentation review |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | ====== Calc Interaction Potential Map ====== | + | ====== Calc Interaction Potential Map ====== |
| ===== Description ===== | ===== Description ===== | ||
| - | This functor generates an interaction potential map, which is a gravitational model between null cells and non-null cells whose values represent the gravitational masses. The denominator is a function of distance to the non-null cells raised to an exponent denoting a friction coefficient. | + | This functor generates an interaction potential map: a gravitational model between null cells and non-null cells, whose values represent the gravitational masses. The denominator is a function of the distance to the non-null cells, raised to an exponent that acts as a friction coefficient. |
| ===== Inputs ===== | ===== Inputs ===== | ||
| - | ^ Name ^ Type ^ Description ^ | + | ^ Name ^ Type ^ Description ^ |
| - | | Source | [[Map Type|Map ]] | Map whose non-null cells correspond to attraction features. | | + | | Source | [[Map Type]] | Map whose non-null cells correspond to source features. The values of the non-null cells are used as the gravity factor. | |
| ===== Optional Inputs ===== | ===== Optional Inputs ===== | ||
| - | ^ Name ^ Type ^ Description ^ Default Value ^ | + | ^ Name ^ Type ^ Description ^ Default Value ^ |
| - | | Mask | [[Map Type|Map ]] | Map whose null cells mask the calculation of the interaction potential. | None | | + | | Mask | [[Map Type]] | Map whose null cells mask the interaction-potential calculation. | .none | |
| - | | Distance Decay Exponent | [[Double Type|Double ]] | Exponent used as a friction coefficient. | 2.0 | | + | | Distance Decay Exponent | [[Real Value Type]] | Exponent used by the decay function applied to the distance from each point to the source features, when calculating the total interaction potential. | 2 | |
| - | | Cell Type | [[Cell Type Type|Cell Type ]] | Data cell type. This type must be compatible with source map values, or an error will be reported during execution. | Signed 32 Bit Integer | | + | | Cell Type | [[Cell Type Type]] | Cell type of the interaction potential map. The calculated potentials are converted to this type, which must be compatible with the values in Source, or this functor reports an error during execution. | Signed 32 Bit Integer | |
| - | | Null Value | [[Int Type|Int ]] | Null Value. | -2147483648 | | + | | Null Value | [[Null Value Type]] | Null value of the interaction potential map. | .default | |
| - | ===== Output ===== | + | ===== Outputs ===== |
| - | ^ Name ^ Type ^ Description ^ | + | ^ Name ^ Type ^ Description ^ |
| - | | Interaction Potential | [[Map Type|Map ]] | Area of each map category in cells. | | + | | Interaction Potential | [[Map Type]] | Map of the total interaction potential of the source features. Interaction Potential has the same dimensions as Source. | |
| ===== Group ===== | ===== Group ===== | ||
| Line 29: | Line 29: | ||
| ===== Notes ===== | ===== Notes ===== | ||
| - | The interaction potential is calculated using float and converted to "Signed 32 Bit Integer". In case cell type is set to "IEEE 754 32 Bit Real", no conversion is done. | + | Total interaction potentials are calculated as real values and converted to the interaction potential map's representable range, where 0 maps to 0 and the greatest potential maps to the greatest value the cell type can represent. No conversion is performed when the interaction potential map's cell type is a floating-point type; the values are kept in their original range in that case. |
| - | The mask map does not mask the feature cells, only the calculation for the null-cells. | + | Mask does not affect which source-feature cells are collected, only the final calculation: a source feature located outside the area indicated by Mask still influences the result. |
| - | For each null cell, the interaction potential is the sum of the mass of each feature cell divided by the distance to it raised to an exponent of decay. | + | The potential of each cell is the sum, over every source feature, of the feature's value divided by the distance between the current cell and the feature, raised to Distance Decay Exponent. |
| - | + | ||
| - | <m 10>p(i) = sum{j=0}{n}{{value(j)}/{dist(i,j)}^de}</m> | + | |
| ===== Internal Name ===== | ===== Internal Name ===== | ||