R: Select parts of a GEOmap

SELGEOmap {GEOmap} | R Documentation

## Select parts of a GEOmap

### Description

Using area, number of points and Lat-Lon Limits, extracts map strokes and creates a new GEOmap

### Usage

    SELGEOmap(MAP, ncut = 3, acut = c(0, 1e+05), proj = NULL, LIM = NULL)

### Arguments

`MAP` | Map structure
`ncut` | minimum number of points in polygon
`acut` | vector, min and max of areas to include
`proj` | map projection
`LIM` | vector, c(lon1, lat1, lon2, lat2)

### Details

Uses splancs function. If proj and LIM are NULL then no selection on limits are used ncut is used to eliminate area calculations with strokes less than the specified number.

### Value

GEOmap LIST

`STROKES` | list
`nam` | name of stroke
`num` | number of points in stroke
`index` | index of stroke
`col` | color of stroke
`style` | style of stroke
`code` | code of stroke
`LAT1` | lower left Lat of stroke
`LAT2` | upper right Lat of stroke
`LON1` | lower left Lon of stroke
`LON2` | upper right Lon of stroke
`POINTS` | list
`lat` | vector of lats
`lon` | vector of lons

### Author(s)

Jonathan M. Lees<jonathan.lees@unc.edu>

### See Also

geoarea

### Examples

    library(geomapdata)
    data(worldmap)
    skam = SELGEOmap(worldmap, ncut=3, acut=c(10000, Inf), proj=NULL, LIM=NULL)

    par(mfrow=c(2,1))

    #######  plot world map, with all lines:
    plotGEOmap(worldmap)
    length(worldmap$STROKES$num)
    ######   same plot with some lines removed:
    plotGEOmap(skam)
    length(skam$STROKES$num)

    #####################
    #####################

[Package GEOmap version 2.4-0 Index]