Generates spatiotemporal point pattern from origins sampled based on real sample dataset.
psim_real(n_events, ppt, start_date = NULL, poly = NULL,
netw = NULL, s_threshold = NULL, step_length = 20, n_origin=50,
restriction_feat=NULL, field=NA,
p_ratio=20, interactive = FALSE, s_range = 150,
s_interaction = "medium", tolerance = 0.07,
crsys = NULL)A list of artificial spatiotemporal point patterns and interaction generated based on a sample (real) data.
number of points
(events) to simulate. Default: 1000.
A vector of integer values can be supplied, such as,
c(a1, a2, ....), where a1, a`2, ...
represent different integer values.
A 3-column matrix or list containing
x - eastings, y - northing, and t - time of occurrence
(in the format: `yyyy-mm-dd')
the start date of the temporal pattern.
The date should be in the format "yyyy-mm-dd".
The temporal pattern will normally cover
1-year period.
(An sf or S4 object) a polygon shapefile defining the extent of the landscape
(An sf or S4 object)
The network path of the landscape
(e.g. road and/or street). Default: NULL.
If provided each event is snapped to the closest
network path/segment.
defines the spatial
perception range of a walker at a given
location. Default: 250 (in the same
linear unit
as the poly - polygon shapefile).
the maximum step taken by a walker from one point to the next.
number of locations to serve as
origins for walkers. Default:50.
(An S4 object) optional
shapefile containing features
in which walkers cannot walk through.
Default: NULL.
a number in the range of [0-1]
(i.e. restriction values) assigned
to all features; or
the name of a numeric field to extract such
restriction values for different classes of
feature.
Restriction value 0 and 1 indicate the
lowest and the highest obstructions, respectively.
Default: NULL.
the smaller of the
two terms of proportional ratios.
For example, a value of 20
implies 20:80 proportional ratios.
Whether to run the process in
interactive mode. Default is FALSE. If TRUE,
a user is able to preview the spatial and temporal models
of the expected distribution of the final simulated
events (points).
A value (in metres), not less than 150,
specifying the maximum range of spatial
interaction across the space. For example, for 150m,
the intervals of spatial interactions are created as
(0, 50], (50 - 100], and (100-150],
representing the "small", "medium", and "large",
spatial interaction ranges, respectively. If
s_range is set as NULL, simulation
focusses only on generating point pattern with
similar spatiotemporal patterns as the sample
dataset.
(string) indicating the
type of spatial interaction to detect.
Default: "medium" (See parameter 's_range')
Pvalue to use for the extraction of
space-time interaction in the sample data. Default
value: 0.05.
(string) the EPSG code of the projection
system of the ppt coordinates. This is only used if
poly argument is NULL.
See "http://spatialreference.org/" for the list of
EPSG codes for different regions of the world.
As an example, the EPSG code for the British National Grid
projection system is: "EPSG:27700".
The spatial and temporal patterns and interactions detected in sample datasets are extrapolated to synthetise larger data size. Details of the spatiotemporal interactions detected in the sample dataset are provided. If the street network of the area is provided, each point is snapped to its nearest street segment.
Davies, T.M. and Hazelton, M.L. (2010), Adaptive kernel estimation of spatial relative risk, Statistics in Medicine, 29(23) 2423-2437. Terrell, G.R. (1990), The maximal smoothing principle in density estimation, Journal of the American Statistical Association, 85, 470-477.