View source: R/filter_islands.R
ms_filter_islands | R Documentation |
Remove small detached polygons, keeping those with a minimum area and/or a minimum number of vertices. Optionally remove null geometries.
ms_filter_islands( input, min_area = NULL, min_vertices = NULL, drop_null_geometries = TRUE, force_FC = TRUE, sys = FALSE, sys_mem = 8 )
input |
spatial object to filter. One of:
|
min_area |
minimum area of polygons to retain. Area is calculated using planar geometry, except for the area of unprojected polygons, which is calculated using spherical geometry in units of square meters. |
min_vertices |
minimum number of vertices in polygons to retain. |
drop_null_geometries |
should features with empty geometries be dropped?
Default |
force_FC |
should the output be forced to be a FeatureCollection (or
Spatial*DataFrame) even if there are no attributes? Default |
sys |
Should the system mapshaper be used instead of the bundled mapshaper? Gives better performance on large files. Requires the mapshaper node package to be installed and on the PATH. |
sys_mem |
How much memory (in GB) should be allocated if using the system
mapshaper ( |
object with only specified features retained, in the same class as the input
library(geojsonio) library(sp) poly <- structure("{\"type\":\"FeatureCollection\", \"features\":[{\"type\":\"Feature\",\"properties\":{}, \"geometry\":{\"type\":\"Polygon\", \"coordinates\":[[[102,2],[102,4],[104,4],[104,2],[102,2]]]}}, {\"type\":\"Feature\",\"properties\":{}, \"geometry\":{\"type\":\"Polygon\", \"coordinates\":[[[100,2],[98,4],[101.5,4],[100,2]]]}}, {\"type\":\"Feature\",\"properties\":{}, \"geometry\":{\"type\":\"Polygon\", \"coordinates\":[[[100,0],[100,1],[101,1],[101,0],[100,0]]]}}]}", class = c("json", "geo_json")) poly <- geojson_sp(poly) plot(poly) out <- ms_filter_islands(poly, min_area = 12391399903) plot(out)
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