MAP_CONTINENTS
Name
MAP_CONTINENTS
Purpose
The MAP_CONTINENTS procedure draws continental boundaries,
filled continents, political boundaries, coastlines, and/or rivers,
over an existing map projection established by MAP_SET. Outlines can
be drawn in low or high-resolution (if the optional high-resolution
CIA World Map database is installed). If MAP_CONTINENTS is called
without any keywords, it draws low-resolution, unfilled continent
outlines.
MAP_SET must be called before MAP_CONTINENTS to establish the
projection type, the center of the projection, polar rotation
and geographic limits.
Keywords not recognized are passed along in _EXTRA to PLOTS and/or
POLYFILL depending on options requested.
Category
MAPPING
Calling Sequence
MAP_CONTINENTS
Inputs
NONE
Input Keyword Parameters
COASTS -- Set this keyword to draw coastlines, islands, and lakes instead of
the default continent outlines. Note that if you are using the
low-resolution map database (if the HIRES keyword is not set), many
islands are drawn even when COASTS is not set. If you are using the
high-resolution map database (if the HIRES keyword is set),
no islands are drawn unless COASTS is set.
COLOR -- The color index of the lines being drawn.
CONTINENTS: Set this keyword to plot the continental boundaries.
This is the default.
Note that if you are using the low-resolution map database
(if the HIRES keyword is not set), outlines for continents, islands,
and lakes are drawn when the CONTINENTS keyword is set. If
you are using the high-resolution map database (if the HIRES keyword
is set), only continental outlines are drawn when the CONTINENTS
keyword is set. To draw islands and lakes when using the
high-resolution map database, use the COASTS keyword.
COUNTRIES -- Set this keyword to draw political boundaries as of 1993.
_EXTRA -- Other keywords passed along to PLOTS/POLYFILL depending on
options selected. Note that command line keywords (like
MLINETHICK) will take precedence over options specified with
_EXTRA or their natural names (like THICK).
FILL_CONTINENTS -- Set this keyword to 1 to fill continent boundaries with
a solid color. The color is set by the COLOR keyword.
Set this keyword to 2 to fill continent boundaries with a
line fill. For line filling, the COLOR, MLINESTYLE,
MLINETHICK, ORIENTATION, and SPACING keywords can be used
to control the type of line fill. Any option valid for
polyfill can also be used (i.e. PATTERN).
HIRES -- Set this keyword to use high-resolution map data instead of the
default low-resolution data. This option is only available if you
have installed the optional high-resolution map datasets. If the
high-resolution data is not available, a warning is printed and
the low-resolution data is used instead.
This keyword can be used in conjunction with the COASTS, COUNTRIES,
FILL_CONTINENTS, and RIVERS keywords.
LIMIT: Set this keyword to a four-element vector
[Lat min, Lon min, Lat max, Lon max ] to only plot continents that
pass through the LIMIT rectangle.
The points (Lat min, Lon min ) and (Lat max, Lon max ) are
the latitudes and longitudes of two points diagonal from each other
on the region�s boundary.
The default is to use the limits from the current map projection.
Note - Line segments for continents which extend outside of the
LIMIT rectangle will still be plotted.
MLINESTYLE -- The line style of the boundaries being drawn.
The default is solid lines.
MLINETHICK -- The thickness of the boundary or fill lines.
The default thickness is 1.
ORIENTATION -- Set this keyword to the counterclockwise angle in degrees
from horizontal that the line fill should be drawn. The
default is 0. This keyword only has effect if the
FILL_CONTINENTS keyword is set to 2.
RIVERS -- Set this keyword to draw rivers.
SPACING -- Set this keyword to the spacing, in centimeters, for a line fill.
This keyword only has effect if the FILL_CONTINENTS keyword is
set to 2. The default is 0.5 centimeters.
T3D: Set this keyword to indicate that the generalized transformation
matrix in !P.T is to be used. If not present, the user-supplied
coordinates are simply scaled to screen coordinates.
USA -- Set this keyword to draw borders for each state in the United States
in addition to continental boundaries.
ZVALUE: Sets the Z coordinate, in normalized coordinates in the
range of 0 to 1, at which to output the continents.
Note - This keyword has effect only if keyword T3D is set and the
transformation is stored in !P.T
Output Keyword Parameters
NONE
Outputs
Draws continents, etc. over the current map display.
Common Blocks
None.
Side Effects
None.
Restrictions
See DESCRIPTION.
Description
See PURPOSE.
Examples
Draw Low-Resolution continents, with high resolution
political boundaries.
MAP_SET
MAP_CONTINENTS
MAP_CONTINENTS,/hires,/countries
DEVELOPMENT NOTES:
This version uses !type=3 and uses the NEW (IDL5) map software.
requires map_struct_append in map_set.pro
Modification History
SVP, 11/96 ; Added header template.
KDM, 05/01 ; Now works with cmagnetic keyword
NOTE: magnetic files are in custom dir, not
IDL distrobution directory. Hard-wired in code.