Package 'rLFT'

Add M values to given feature

Description

Add M values to a given linear feature and store them in the m-coordinate of the sf object. Returns the new sf object with added m-values. For more information on m-values and linear referencing see: http://desktop.arcgis.com/en/arcmap/10.3/guide-books/linear-referencing/what-is-linear-referencing.htm

Usage

addMValues(sfDataObject)

Arguments

sfDataObject

An sf object. Must be a LINESTRING, POLYGON, MULTIPOLYGON, or MULTILINESTRING

Value

Returns the new sfDataObject with added m-values. The class of the output is sf.

Examples

library(rLFT)
data("shpObject")
# Assign M Values to each vertex
mValues <- addMValues(shpObject)
print("M Values Added")
head(st_coordinates(mValues))

---

Boundary Convexity Tool

Description

Calculates raw convexity, convexity index, and sinuosity of a given sf object and returns a data frame with all measurements for each step and feature. If provided, the data will also be output to a tab delimited file.

Usage

bct(sfDataObject, step, window, ridName = NULL, filename = "")

Arguments

sfDataObject	An sf Object containing shape file data.
step	A numeric describing the distance between measurements along an arc.
window	A numeric describing the diameter of the window used to measure convexity.
ridName	A character denoting the column name where the unique ID for each feature is stored in given sf object.
filename	A character denoting the name of the file you wish to output convexity data to in tab delimited format. Must have the .txt extension.

Details

This function will reject any sf object with a geographic coordinate system, so consider projecting your features. Your sf object must be of either type LINESTRING, MULTILINESTRING, POLYGON, or MULTIPOLYGON. If a given POLYGON or MUTLIPOLYGON contains inner rings, they will be ignored. If a unique ID Column name is not provided, the function will generate a unique ID for each feature. The arguments step and window can be any non-negative numeric. The argument ridName MUST be a character indicating the name of the column in your sf object where the route id is stored.

Value

The output of this function is a data.frame that contains all measurements for each step and feature.

Reference

Albeke, S.E. et al. “Measuring boundary convexity at multiple spatial scales using a linear “moving window” analysis: an application to coastal river otter habitat selection.” Landscape Ecology 25 (2010): 1575-1587. [linked phrase](https://link.springer.com/article/10.1007/s10980-010-9528-4)

Examples

library(rLFT)
data("shpObject")
#store convexity output data in a variable 'outputTable'
outputTable <- bct(shpObject, step = 50, window = 100, ridName = "RID")

---

An example sf object outlining boundaries of a group of islands in Alaska in the lat/lon CRS.

Description

A dataset with coordinates (x, y, z) of 3 linear features with a geometry type of MULTIPOLYGON and a geographic coordinate system (longlat)

Usage

latlongShpObject

Format

A data frame with 1 row and 10 variables

---

An example sf object with geometry type of POINT, used for testing.

Description

An example sf object with geometry type of POINT, used for testing.

Usage

pointObject

Format

An object of class sf (inherits from data.frame) with 1 rows and 2 columns.

---

An example sf object outlining boundaries of a group of islands in Alaska cast as POLYGON.

Description

A dataset with coordinates (x, y) of 37 features with a geometry type of POLYGON and a projected coordinate system (aea). These features represent the same data as 'shpObject' but this sf object has been cast to be of geometry type POLYGON. There are also inner polygons on some features.

Usage

polygonShpObject

Format

A data frame with 37 rows and 2 variables

Id

Id's of all features

geometry

coordinates of feature (x,y)

---

An example sf object outlining boundaries of a group of islands in Alaska cast as LINESTRING.

Description

A dataset with coordinates (x, y) of 37 linear features with a geometry type of LINESTRING and a projected coordinate system (aea). These particular features represent several small islands in Alaska.

Usage

shpObject

Format

A data frame with 37 rows and 2 variables

RID

Route ID of the features

geometry

coordinates of feature (x, y)

---