Documentation for SpatialMap class from SLiM
This class represents a "spatial map": a grid of values overlaid across a simulated spatial landscape, representing some variable that varies across space. This variable could be something environmental (elevation, temperature), something that affects local dynamics (local carryingcapacity density, local mean dispersal distance), or anything else needed for the model (years since the last wildfire in that location, for example). A new spatial map is created with the defineSpatialMap() method of Subpopulation, because spatial maps are tightly associated with subpopulations; in particular, they must share the spatial bounds of any subpopulation to which they have been added, because the spatial map's grid of values is overlaid onto those spatial bounds. There is a constructor for SpatialMap, but it is only used to copy an existing spatial map: (object<SpatialMap>$)SpatialMap(string$ name, object<SpatialMap>$ map) Creates a new SpatialMap object that is a copy of map, named name. That can be useful if you wish to derive a new spatial map from an existing map, but it is not very commonly used. Usually a new map is created with defineSpatialMap(), often using spatial data from a PNG image file that has been loaded using the Eidos class Image. If you wish to add a spatial map to additional subpopulations, beyond the subpopulation for which the map was originally defined, the Subpopulation method addSpatialMap() can be used to do so, thereby sharing the map across more than one subpopulation. The SpatialMap class was added in SLiM 4.1; before that, spatial maps were a sub-component of Subpopulation. Splitting spatial maps out into their own class provides more flexibility to extend their capabilities in the future. This class has the following methods (functions):
This class has the following properties:
A property of type integer or logical or string or float or string or integer. This property is a constant, so it is not modifiable. Property Description: The dimensions of the spatial map's grid of values, in the order of the components of the map's spatiality. For example, a map with spatiality "xz" and a grid of values that is 500 in the "x" dimension by 300 in the "z" dimension would return c(500, 300) for this property.
A property of type integer or logical or string or float or string or integer. It is of length one (a singleton). This property is a variable, so it is modifiable. Property Description: Whether interpolation between grid values is enabled (T) or disabled (F). The initial value of this property is set by defineSpatialMap(), but it can be changed. The interpolation performed is linear; for cubic interpolation, use the interpolate() method.
A property of type integer or logical or string or float or string or integer. It is of length one (a singleton). This property is a constant, so it is not modifiable. Property Description: The name of the spatial map, usually as provided to defineSpatialMap(). The names of spatial maps must be unique within any given subpopulation, but the same name may be reused for different spatial maps in different subpopulations. The name is used to identify a map for methods such as spatialMapValue(), and is also used for display in SLiMgui.
A property of type integer or logical or string or float or string or integer. This property is a constant, so it is not modifiable. Property Description: The spatial bounds to which the spatial map is aligned. These bounds come from the subpopulation that originally created the map, with the defineSpatialMap() method, and cannot be subsequently changed. All subpopulations that use a given spatial map must match that map's spatial bounds, so that the map does not stretch or shrink relative to its initial configuration. The components of the spatial bounds of a map correspond to the components of the map's spatiality; for example, a map with spatiality "xz" will have bounds (x0, z0, x1, z1); bounds for "y" are not included, since that dimension is not used by the spatial map.
A property of type integer or logical or string or float or string or integer. It is of length one (a singleton). This property is a constant, so it is not modifiable. Property Description: The spatiality of the map: the subset of the model's dimensions that are used by the spatial map. The spatiality of a map is configured by defineSpatialMap() and cannot subsequently be changed. For example, a 3D model (with dimensionality "xyz") might define a 2D spatial map with spatiality "xz", providing spatial values that do not depend upon the "y" dimension. Often, however, the spatiality of a map will match the dimensionality of the model.
A property of type integer or logical or string or float or string or integer. It is of length one (a singleton). This property is a variable, so it is modifiable. Property Description: A user-defined integer value. The value of tag is initially undefined, and it is an error to try to read it; if you wish it to have a defined value, you must arrange that yourself by explicitly setting its value prior to using it elsewhere in your code. The value of tag is not used by SLiM; it is free for you to use. See also the getValue() and setValue() methods (provided by the Dictionary class; see the Eidos manual), for another way of attaching state to spatial maps.
Other SpatialMap:
add(),
blend(),
changeColors(),
changeValues(),
divide(),
exp(),
gridValues(),
interpolate(),
mapColor(),
mapImage(),
mapValue(),
multiply(),
power(),
range(),
rescale(),
sampleImprovedNearbyPoint(),
sampleNearbyPoint(),
smooth(),
subtract()