Package 'pathroutr'

Title: An R Package for (Re-)Routing Paths Around Barriers
Description: The `pathroutr` package aims to provide a set of tools for routing marine animal tracks around land barriers based on the shortest path through a visibility graph network. The foundation of the package is a graph network created from a Delaunay Triangle mesh created from the vertices of land polygons within the study area. Any network edges that cross or fall completely within the land (barrier) polygons are removed.
Authors: Josh London [aut, cre]
Maintainer: Josh London <[email protected]>
License: CC0
Version: 0.2.1
Built: 2024-10-27 04:06:15 UTC
Source: https://github.com/jmlondon/pathroutr

Help Index

Alaska coastline

Description

Alaska 1:250000 coastal data polygon. This is provided by the Alaska Department of Natural Resources and was obtained from their open data portal (https://gis.data.alaska.gov/datasets/alaska-1250000). Note, only those polygons that intersect with the bounding box of our harbor seal movement are included.

Usage

akcoast

Format

Simple feature collection with 273 features and 5 fields:

geometry

POLYGON

Source

https://gis.data.alaska.gov/datasets/alaska-1250000

Identify track points that intersect with a barrier polygon

Description

This function identifies the segments of consecutive points that intersect with the barrier polygon feature. The result is a data frame of segment records that identify portions of the track that will need to be re-routed. The result from this function can be directly passed into the prt_nearestnode().

Usage

get_barrier_segments(trkpts, barrier)

Arguments

trkpts

Simple Feature points ('sf', 'sfc_POINT'/'sfc_MULTIPOINT') that represent track points. Order is accepted as is and the bounding box of trkpts should be within the bounding box of the barrier polygon.
barrier

Simple Feature polygon ('sf', 'sfc_POLYGON'/'sfc_MULTIPOLYGON') representing the barrier feature. Should be the same barrier as supplied to the prt_visgraph() function.

Value

data.frame representing segments of consecutive points that intersect with barrier feature. the start_pt and end_pt geometry columns represent the bookend points for each segment that do not intersect with the barrier feature. The n_pts column is the number of points to be re-routed.

land barrier

Description

A polygon dataset used to test and demonstrate package functions for routing paths around barriers

Usage

land_barrier

Format

Simple feature collection with 19 features and 0 fields:

geometry

MULTIPOLYGON

Source

geopackage file available in extData

points of interest

Description

A point dataset used to test and demonstrate package functions for routing paths around barriers

Usage

poi

Format

Simple feature collection with 67 features and 0 fields:

geometry

MULTIPOINT

Source

geopackage file available in extData

Extend a path to include given start and end points

Description

Extend a path to include given start and end points

Usage

prt_extend_path(l_geom, start_pt, end_pt)

Arguments

l_geom

geometry passed from inside prt_shortpath()
start_pt

start point
end_pt

end point

Value

linestring

Find the nearest node for start and end points in segs_tbl

Description

Find the nearest node for start and end points in segs_tbl

Usage

prt_nearestnode(segs_tbl, vis_graph)

Arguments

segs_tbl

output from get_barrier_segments()
vis_graph

sfnetwork output from prt_visgraph()

Value

data frame with updated columns for nearest start and end nodes

Re-route track points around barrier feature

Description

This is a convenience wrapper, and the suggested function, for re-routing a trkpts series of ordered POINT features around a barrier polygon via vis_graph built with the prt_visgraph() function. The output can be used as a starting point for a custom process to replace the original geometry. Or, provide the output tibble directly to prt_update_points() along with trkpts for simply updating in place.

Usage

prt_reroute(trkpts, barrier, vis_graph, blend = TRUE)

Arguments

trkpts

Simple Feature points ('sf', 'sfc_POINT'/'sfc_MULTIPOINT') that represent track points. Order is accepted as is and the bounding box of trkpts should be within the bounding box of the barrier polygon.
barrier

Simple Feature polygon ('sf', 'sfc_POLYGON'/'sfc_MULTIPOLYGON') representing the barrier feature. Should be the same barrier as supplied to the prt_visgraph() function.
vis_graph

sfnetwork from prt_visgraph()
blend

boolean whether to blend start/end points into network

Value

a two-column tibble with column fid representing the row index in trkpts to be replaced by the new geometry in geometry column. If trkpts and barrier do not spatially intersect and empty tibble is returned.

Calculate the shortest path through a visibility network between two points

Description

Calculate the shortest path through a visibility network between two points

Usage

prt_shortpath(segs_tbl, vis_graph, blend = TRUE)

Arguments

segs_tbl

tbl from get_barrier_segments()
vis_graph

sfnetwork from prt_visgraph()
blend

boolean whether to blend start/end points into network

Value

segs_tbl data frame with added geometry column for shortest path LINESTRING that connects the start_pt and end_pt coordinates

Trim tracks to start and end outside barrier

Description

Trim tracks to start and end outside barrier

Usage

prt_trim(trkpts, barrier)

Arguments

trkpts

Simple Feature points ('sf', 'sfc_POINT'/'sfc_MULTIPOINT') that represent track points. Order is accepted as is and the bounding box of trkpts should be within the bounding box of the barrier polygon.
barrier

Simple Feature polygon ('sf', 'sfc_POLYGON'/'sfc_MULTIPOLYGON') representing the barrier feature. Should be the same barrier as supplied to the prt_visgraph() function.

Update track points with fixed geometry

Description

Original geometry is updated in place and (currently) no record of those points that were updated is provided.

Usage

prt_update_points(rrt_pts, trkpts)

Arguments

rrt_pts

output from prt_reroute() or tibble with rrt_idx and geometry columns
trkpts

original trkpts Simple Features Collection

Value

trkpts with updated geometry

Create a visibility graph

Description

Create a visibility graph

Usage

prt_visgraph(
  barrier,
  buffer = 0,
  centroids = FALSE,
  centroid_limit = 1e+07,
  aug_points = NULL
)

Arguments

barrier

simple feature 'POLYGON' or 'MULTIPOLYGON' that can be cast into 'POLYGON'
buffer

integer specifying buffer distance for barrier
centroids

logical whether to include centroids in the mesh
centroid_limit

integer minimum size (m^2) for adding centroid to triangles
aug_points

simple feature 'POINT' or 'MULTIPOINT' as additional nodes

Value

SpatialLinesNetwork

Spatial predicates

Description

These are custom spatial predicate functions that are negated versions of the spatial predicates st_within(), st-crosses(), and st_intersects

Usage

not_crosses(x, y)

not_within(x, y)

not_intersects(x, y)

Arguments

x, y

simple features.