extentofview

Total length of the lines in a number of directions from the cell under consideration to the first cell with a different value.

```
Result = extentofview(classes, nrdirections)
```

- nrdirections
- non spatial scalar
- classes
- spatial boolean, nominal, ordinal
- Result
- spatial scalar

`--unittrue` or `--unitcell`

`--unittrue`- distance is measured in true distance (default)
`--unitcell`- distance is measured in number of cell lengths

For each cell and for each direction this function determines the distance untill a cell with a different value than the current cell value is encountered. For each cell these distances are summed. To calculate the average distance, divide the result by the number of distances. This average extent of view can be used as an indicator for the openness of the landscape, for example.

This operation belongs to the group of Neigbourhood operator; operators for visibility analysis