generateLineHash: Generate a unique ID for line segments
In sharpshootR: A Soil Survey Toolkit

Description Usage Arguments Details Value Note Author(s)

Generate a unique ID for a line segment, based on the non-cryptographic murmur32 hash.

1	generateLineHash(x, precision=-1, algo='murmur32')

`x`	a `SpatialLinesDataFrame` object, with 1 line segment per feature (e.g. simple features)
`precision`	digits are rounded to this many places to the right (negative) or left (positive) of the decimal place
`algo`	hash function algorithm

The input SpatialLinesDataFrame object must NOT contain multi-part features. The precision specified should be tailored to the coordinate system in use and the snapping tolerance used to create join decision line segments. A precision of 4 is reasonable for geographic coordinates (snapping tolerance of 0.0001 degrees or ~ 10 meters). A precision of -1 (snapping tolerance of 10 meters) is reasonable for projected coordinate systems with units in meters.

A vector of unique IDs created from the hash of line segment start and end vertex coordinates. Unique IDs are returned in the order of records of x and can therefore be saved into a new column of the associated attribute table.

An error is issued if any non-unique IDs are generated. This could be casued by using coordiantes that do not contain enough precision for unique hashing.

D.E. Beaudette

sharpshootR documentation built on May 2, 2019, 4:46 p.m.