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Automatic limits for basemap

Source: R/auto_limits.R
auto_limits.Rd

Find limits for a basemap from a data frame.

Usage

auto_limits(
  data,
  lon = NULL,
  lat = NULL,
  proj.in = 4326,
  proj.out = NULL,
  expand.factor = NULL,
  verbose = FALSE
)

Arguments

data

Data frame or a spatial object containing data for which the limits should be calculated.

lon, lat

Names of longitude and latitude columns in data as character or integer index. If NULL, the column names are guessed.

proj.in

Original CRS projection. Must be defined as character argument.

proj.out

Resulting map projection. See transform_coord.

expand.factor

Expansion factor for map limits. Set to NULL to ignore.

verbose

Logical indicating whether information about the projection and guessed column names should be returned as message. Set to FALSE to make the function silent.

Value

A list of limits and projections in proj.in and proj.out formats.

Details

This is an internal function, which is automatically run by the basemap function.

See also

Other customize shapefiles: reorder_layers(), theme_map()

Author

Mikko Vihtakari

Examples

auto_limits(data = expand.grid(lon = c(-120, 180, 120),
   lat = c(60, 60, 80)))
#> $ddLimits
#>       xmin       xmax       ymin       ymax 
#> -139.10661  139.10661   50.94316   90.00000 
#> 
#> $projLimits
#>       xmin       xmax       ymin       ymax 
#> -2886578.7  2886578.7   544589.7  3333134.0 
#> 
#> $projBound
#> Geometry set for 1 feature 
#> Geometry type: POLYGON
#> Dimension:     XY
#> Bounding box:  xmin: -2886579 ymin: 544589.7 xmax: 2886579 ymax: 3333134
#> Projected CRS: WGS 84 / Arctic Polar Stereographic
#> POLYGON ((-2886579 544589.7, -2886579 3333134, ...
#> 
#> $proj.in
#> Coordinate Reference System:
#>   User input: EPSG:4326 
#>   wkt:
#> GEOGCRS["WGS 84",
#>     ENSEMBLE["World Geodetic System 1984 ensemble",
#>         MEMBER["World Geodetic System 1984 (Transit)"],
#>         MEMBER["World Geodetic System 1984 (G730)"],
#>         MEMBER["World Geodetic System 1984 (G873)"],
#>         MEMBER["World Geodetic System 1984 (G1150)"],
#>         MEMBER["World Geodetic System 1984 (G1674)"],
#>         MEMBER["World Geodetic System 1984 (G1762)"],
#>         MEMBER["World Geodetic System 1984 (G2139)"],
#>         ELLIPSOID["WGS 84",6378137,298.257223563,
#>             LENGTHUNIT["metre",1]],
#>         ENSEMBLEACCURACY[2.0]],
#>     PRIMEM["Greenwich",0,
#>         ANGLEUNIT["degree",0.0174532925199433]],
#>     CS[ellipsoidal,2],
#>         AXIS["geodetic latitude (Lat)",north,
#>             ORDER[1],
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>         AXIS["geodetic longitude (Lon)",east,
#>             ORDER[2],
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>     USAGE[
#>         SCOPE["Horizontal component of 3D system."],
#>         AREA["World."],
#>         BBOX[-90,-180,90,180]],
#>     ID["EPSG",4326]]
#> 
#> $proj.out
#> Coordinate Reference System:
#>   User input: EPSG:3995 
#>   wkt:
#> PROJCRS["WGS 84 / Arctic Polar Stereographic",
#>     BASEGEOGCRS["WGS 84",
#>         ENSEMBLE["World Geodetic System 1984 ensemble",
#>             MEMBER["World Geodetic System 1984 (Transit)"],
#>             MEMBER["World Geodetic System 1984 (G730)"],
#>             MEMBER["World Geodetic System 1984 (G873)"],
#>             MEMBER["World Geodetic System 1984 (G1150)"],
#>             MEMBER["World Geodetic System 1984 (G1674)"],
#>             MEMBER["World Geodetic System 1984 (G1762)"],
#>             MEMBER["World Geodetic System 1984 (G2139)"],
#>             ELLIPSOID["WGS 84",6378137,298.257223563,
#>                 LENGTHUNIT["metre",1]],
#>             ENSEMBLEACCURACY[2.0]],
#>         PRIMEM["Greenwich",0,
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>         ID["EPSG",4326]],
#>     CONVERSION["Arctic Polar Stereographic",
#>         METHOD["Polar Stereographic (variant B)",
#>             ID["EPSG",9829]],
#>         PARAMETER["Latitude of standard parallel",71,
#>             ANGLEUNIT["degree",0.0174532925199433],
#>             ID["EPSG",8832]],
#>         PARAMETER["Longitude of origin",0,
#>             ANGLEUNIT["degree",0.0174532925199433],
#>             ID["EPSG",8833]],
#>         PARAMETER["False easting",0,
#>             LENGTHUNIT["metre",1],
#>             ID["EPSG",8806]],
#>         PARAMETER["False northing",0,
#>             LENGTHUNIT["metre",1],
#>             ID["EPSG",8807]]],
#>     CS[Cartesian,2],
#>         AXIS["easting (X)",south,
#>             MERIDIAN[90,
#>                 ANGLEUNIT["degree",0.0174532925199433]],
#>             ORDER[1],
#>             LENGTHUNIT["metre",1]],
#>         AXIS["northing (Y)",south,
#>             MERIDIAN[180,
#>                 ANGLEUNIT["degree",0.0174532925199433]],
#>             ORDER[2],
#>             LENGTHUNIT["metre",1]],
#>     USAGE[
#>         SCOPE["Polar research."],
#>         AREA["Northern hemisphere - north of 60°N onshore and offshore, including Arctic."],
#>         BBOX[60,-180,90,180]],
#>     ID["EPSG",3995]]
#>