Import Linear Habitat Mask
Construct a linearmask from line data in a text file, a polyline shapefile, a dataframe or a SpatialLinesDataFrame object.
data frame or SpatialLinesDataFrame
length of each discretized segment
numeric criterion for joining mask points
logical; if TRUE the igraph representation of the mask is saved as an attribute
logical; if TRUE then
other arguments passed to
Only one of ‘file’ or ‘data’ should be specified. The file name should include the extension (e.g., "silverstream.shp").
Input from a text file, polyline shapefile or dataframe is first converted to a SpatialLinesDataFrame object. Points are spaced equally along each SpatialLine, starting at spacing / 2.
For dataframe input via
data the coordinates are expected to be
in columns ‘x’ and ‘y’; if these names are missing, or input is from a
file, the first two columns are used.
spacingfactor is used by
asgraph to determine
which points are joined when computing distances. It should be between
1 and 2.
A ‘linearmask’ object, i.e. a ‘mask’ object in which each point
represents a line segment of length
spacing, and with
additional attributes ‘SLDF’, ‘spacingfactor’ and possibly ‘graph’ (see
A valid shapefile includes at least three files with extensions ‘.shp’, ‘.dbf’ and ‘.shx’. The full name of the .shp file is provided as the ‘file’ argument of
read.linearmask. The shapefile name without any extension is used as the first argument to the maptools function
Line-level covariates are copied from SpatialLinesDataFrame input. Point-specific covariates may be added
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