lidR: merge_spatial – R documentation

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merge_spatial

Merge a point cloud with a source of spatial data

Description

Merge a point cloud with a source of spatial data. It adds an attribute along each point based on a value found in the spatial data. Sources of spatial data can be a SpatialPolygons*) , a sf data.frame or a Raster*.

SpatialPolygons*, sf: it checks if the points belongs within each polygon. If the parameter attribute is the name of an attribute in the table of attributes it assigns to the points the values of that attribute. Otherwise it classifies the points as boolean. TRUE if the points are in a polygon, FALSE otherwise.
RasterLayer: it attributes to each point the value found in each pixel of the RasterLayer.
RasterStack or RasterBrick must have 3 channels for RGB colors. It colorizes the point cloud with RGB values.

Usage

merge_spatial(las, source, attribute = NULL)

Arguments

`las`	An object of class `LAS`
`source`	An object of class `SpatialPolygons*` or `sf` or `RasterLayer` or a `RasterStack` or `RasterBrick` with RGB colors.
`attribute`	character. The name of an attribute in the table of attributes of the shapefile or the name of a new column in the LAS object. Not relevant for RGB colorization.

Value

An object of the class LAS.

Examples

LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
shp     <- system.file("extdata", "lake_polygons_UTM17.shp", package = "lidR")

las   <- readLAS(LASfile, filter = "-keep_random_fraction 0.1")
lakes <- sf::st_read(shp)

# The attribute "inlake" does not exist in the shapefile.
# Points are classified as TRUE if in a polygon
las    <- merge_spatial(las, lakes, "inlakes")     # New attribute 'inlakes' is added.
forest <- filter_poi(las, inlakes == FALSE)
#plot(forest)

# The attribute "LAKENAME_1" exists in the shapefile.
# Points are classified with the values of the polygons
las <- merge_spatial(las, lakes, "LAKENAME_1")     # New column 'LAKENAME_1' is added.

lidR

Airborne LiDAR Data Manipulation and Visualization for Forestry Applications

v3.1.2

GPL-3

Authors

Jean-Romain Roussel [aut, cre, cph], David Auty [aut, ctb] (Reviews the documentation), Florian De Boissieu [ctb] (Fixed bugs and improved catalog features), Andrew Sánchez Meador [ctb] (Implemented wing2015() for segment_snags()), Bourdon Jean-François [ctb] (Contributed to Roussel2020() for track_sensor()), Gatziolis Demetrios [ctb] (Implemented Gatziolis2019() for track_sensor())

Initial release

2021-03-11