rland: Produces landscapes with descriptive statistics within input...

In gregorp/rlandscape: Generates random landscapes with specifiable spatial characteristics

Description

Uses the results from a series of regressions to find appropriate control parameters to call rlandscape and produce output landscapes with input characteristics. Useful for generating series of landscapes. Any descriptive statistics not specified will be allowed to vary freely. If not using a complete filepath set your working directly appropriately! You may need to increase effort (and wait a long time!) if the constraints are very narrow. About 0.5, 0.25, and 25 are the minimum ranges I'd recommend for degMean, degSD and areaCV, respectively.

Usage

rland(targets = list(), bounds = list(), reps = 10, effort = 0.95,
  filename = "landscape", saveAdj = TRUE, saveAreas = TRUE,
  saveSummary = TRUE, savePlot = FALSE, saveLand = FALSE,
  setSeed = NULL, method = c("linear", "random"), ...)

Arguments

targets	a list with min and max targets for any or all of the landscape characteristics. Targetable characteristics are n, degMean, degSD, areaCV and hAsp. Each item should be of the form n = c(nMin, nMax). It's okay if min == max.
bounds	a list with min and max allowable values for any or all of the landscape characteristics. (Input format as targets. hAsp is ignored as it has no associated randomness). Unspecified characteristics will be unrestricted. Works quickly if the min and max bounds cover the min and max targets with some wiggle room.
reps	the number of landscapes with these characteristics to create.
effort	the maximum failure rate to not self-terminate. Evaluated every 500 tries, default 0.95.
filename	character string prefix for all saved files created. Can include a filepath.
saveAdj	boolean, whether or not to save adjacency tables. Default TRUE
saveAreas	boolean, whether or not to save area tables. Default TRUE
saveSummary	boolean, whether or not to save summary statistics. Default TRUE
savePlot	boolean, whether or not to save plots. Default FALSE
saveLand	boolean, whether or not to save landscapes as R objects. Default FALSE
setSeed	single integer or NULL (default). If a value, will set the random seed to that value before simulations so that behavior can be reproduced.
method	Charachter, the name of the function that takes targets as arguments and retuns parameters for rlandscape. "linear" and "random" work, other methods may be added in the future. are built-in. Defaults to the linear method.
...	Additional parameters passed to plot if applicable.

Details

As for the methods, "linear" uses the linear models as described in the paper (in review). The "random" option picks completely random parameters ignoring the targets. It opens the possibility of more pathological landscapes. Generalized Additive Models might be available soon as a seperate download. Currently, the models I have for that are too big to put on CRAN.

See the examples at the bottom! The defaults for targets are list(n = c(30, 120), areaCV = c(40, 70), degMean = c(4.5, 5.5), degSD = c(1, 2), hAsp = c(1, 3)) Any of the targets that are not set explicitly will revert to these defaults. Note that degMean must be between 2 and 6, degSD should be positive and less than 3, and areaCV needs to be positive, below 40 is small and above 80 is big, though it is unbounded above. hAsp is the horizontal to vertical aspect ratio, so a value of 2 is equivalent to a 90-degree rotation of a value of 1/2.

Bounds are specified in the same way as targets. hAsp is not eligible for bounds because the targets are always hit exactly.

Use the method = "random" to ignore the targets and bounds and just pick control parameters randomly.

If saveLand = TRUE is used, each individual 'landscape' object will be writtent to its own .rds file. These can be read into R using the readRDS function. Any other objects saved (adjacency lists, areas, summary statistics, plots) are saved in common file formats such as .txt or .png.

Value

Returns the number of successes and failures. All other results are written to file.

See Also

rlandscape

Examples

## Not run: 
rland(reps = 2, setSeed = 47)
rland(reps = 5, method = "random", saveLand = TRUE, savePlot = TRUE)
rland(targets = list(n = c(100, 100), areaCV = c(40, 60)), reps = 5, savePlot = TRUE)
rland(targets = list(n = c(30, 80), degMean = c(5, 5.5), areaCV = c(30, 80), degSD = c(1, 2)),
    bounds = list(n = c(30, 80), degMean = c(4.9, 5.6), areaCV = c(25, 85), degSD = c(0.9, 2.1)))

## End(Not run)

gregorp/rlandscape documentation built on May 17, 2019, 8:36 a.m.