Description Usage Arguments Details Value Warning Author(s) References See Also Examples
Get map lines in the model projection units.
1 | get.map.lines.M3.proj(file, database = "state", units, ...)
|
file |
File name of Models3-formatted file providing the model projection. |
database |
Geographical database to use. Choices include
“state” (default), “world”, “worldHires”,
“canusamex”, etc. Use “canusamex” to get the national
boundaries of the Canada, the USA, and Mexico, along with the
boundaries of the states. The other choices (“state”,
“world”, etc.) are the names of databases included with the
maps and mapdata packages. (See the
|
units |
Units for coordinates of grid rows or columns. Must be one of “m”, “km”, or “deg”. If unspecified, the default is “deg” if the file has a longitude/latitude grid, and “km” otherwise. |
... |
Other arguments to pass to |
This function depends on the maps and mapdata
packages to get the appropriate map boundary lines (for states,
countries, etc.), ncdf4 to read the projection information from
the Models3-formatted file (using a call to function
get.proj.info.M3
), and rgdal (which is an interface to
GDAL (Geospatial Data Abstraction Library, http://www.gdal.org)
to project the boundary lines to the specified projection.
Map lines for the projection described in file
in either
kilometers or meters (depending on value of units.km). This is a
matrix, with x-coordinates in the first column and y-coordinates in
the second column.
This function will only work with Lambert conic conformal or polar stereographic projections.
Jenise Swall
get.proj.info.M3
, map
,
project
, get.canusamex.bds
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | ## Find the path to the demo file.
polar.file <- system.file("extdata/surfinfo_polar.ncf", package="M3")
## Read in the terrain elevation variable.
elev <- get.M3.var(file=polar.file, var="HT")
## Make a plot.
image(elev$x.cell.ctr, elev$y.cell.ctr, elev$data[,,1],
xlab="Projection x-coord (km)", ylab="Projection y-coord (km)",
zlim=range(elev$data[,,1]), col=heat.colors(15))
## Superimpose national boundaries on the plot
nat.bds <- get.map.lines.M3.proj(file=polar.file, database="world")$coords
lines(nat.bds)
## Subset to a smaller geographic area in southwestern U.S.
subset.elev <- var.subset(elev, llx=-2000, urx=0, lly=-6500, ury=-4000)
## Make a plot of this subset.
image(subset.elev$x.cell.ctr, subset.elev$y.cell.ctr,
subset.elev$data[,,1], xlab="Projection x-coord (km)",
ylab="Projection y-coord (km)", zlim=range(subset.elev$data[,,1]),
col=heat.colors(15))
## Superimpose Mexico, US, and Candadian national borders on the plot,
## along with state borders.
canusamex.bds <- get.map.lines.M3.proj(file=polar.file, "canusamex")$coords
lines(canusamex.bds)
|
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