1 Spatial spreading/distances methods

Spatial contagion is a key phenomenon for spatially explicit simulation models. Contagion can be modelled using discrete approaches or continuous approaches. Several functions assist with these:

adj
An optimized (i.e., faster) version of adjacent
cir
Identify pixels in a circle around a SpatialPoints* object
directionFromEachPoint
Fast calculation of direction and distance surfaces
distanceFromEachPoint
Fast calculation of distance surfaces
rings
Identify rings around focal cells (e.g., buffers and donuts)
spokes
TO DO: need description
spread
Contagious cellular automata
wrap
Create a torus from a grid

2 Spatial agent methods

Agents have several methods and functions specific to them:

crw
Simple correlated random walk function
heading
Determines the heading between SpatialPoints*
makeLines
Makes SpatialLines object for, e.g., drawing arrows
move
A meta function that can currently only take "crw"
specificNumPerPatch
Initiate a specific number of agents per patch

3 GIS operations

In addition to the vast amount of GIS operations available in R (mostly from contributed packages such as sp, raster, maps, maptools and many others), we provide the following GIS-related functions:

equalExtent
Assess whether a list of extents are all equal

4 Map-reduce - type operations

These functions convert between reduced and mapped representations of the same data. This allows compact representation of, e.g., rasters that have many individual pixels that share identical information.

rasterizeReduced
Convert reduced representation to full raster

5 Random Map Generation

It is often useful to build dummy maps with which to build simulation models before all data are available. These dummy maps can later be replaced with actual data maps.

gaussMap
Creates a random map using Gaussian random fields
randomPolygons
Creates a random polygon with specified number of classes

6 SELES-type approach to simulation

These functions are essentially skeletons and are not fully implemented. They are intended to make translations from SELES. You must know how to use SELES for these to be useful:

agentLocation
Agent location
initiateAgents
Initiate agents into a SpatialPointsDataFrame
numAgents
Number of agents
probInit
Probability of intiating an agent or event
transitions
Transition probability

7 Package options

SpaDES packages use the following options to configure behaviour:

  • spades.lowMemory: If true, some functions will use more memory efficient (but slower) algorithms. Default FALSE.

See also

Useful links: