# st_urban_sprawl: Calculate urban sprawl In ggRaver/Lslide: Functions for object-oriented image analysis in landslide science

## Description

This function calculates the urban sprawl of urban area.

## Usage

 ```1 2 3 4 5``` ```st_urban_sprawl(geom.urban, geom.boundary = NULL, dist = c(100, 100), trans = function(x, trans.k) { x - 1 + 1/(x + trans.k) }, trans.k = 1, tol = 0.1, extent = NULL, force.extent = FALSE, precision = 0, do.preProcessing = TRUE, env.rsaga = NULL, use.saga = FALSE, return.geom = FALSE, quiet = TRUE) ```

## Arguments

 `geom.urban` polygon of class sf representing the fragmentation geometry `geom.boundary` polygon of class sf representing subregions, e.g. administrative boundaries `dist` vector containing distance between lines in x and y direction. Default: c(100, 100) [m] `trans` transformation function x-1+1/(x+trans.k) with x as free line and trans.k a constant `trans.k` constant in km for transformation function trans. Default: 1 `tol` tolerance value for intersection with erased lines. Buffering procedure is used.Default: 0.1 [m] `extent` Numeric value representing extent for area. Format of vector: c(xmin, xmax, ymax, ymin) . Default: NULL `force.extent` If TRUE extent is used instead of geom.boundary (if both are present). Default: FALSE `precision` precision for process. See sf::st_set_precision(). Default: 0 `do.preProcessing` If TRUE (default), the input of geom.frag is, first, dissolved to single part feature, and second, splitted to multi-parts. By this step it is assured, that polygon connected to each other are summarized `env.rsaga` environment of SAGA GIS. If st_erase fails then SAGA GIS erase is used. Default: NULL, but in function call if not set: RSAGA::rsaga.env() `use.saga` use SAGA GIS for erase process. Default: FALSE `return.geom` If set to TRUE, intermediate geometries are returned as well. Default: FALSE `quiet` If set to FALSE, actual state is printed to console. Default: TRUE.

## Value

strong urban sprawl: 40-50

ggRaver/Lslide documentation built on June 20, 2019, 2:29 p.m.