coyote: CGMAPCONTINENTS__DEFINE

Description
Provides an object wrapper to the cgMAP_CONTINENTS or the cgMap_GSHHS commands.
Coyote Library routines are required.
Categories
Graphics, Map Projections
Author
FANNING SOFTWARE CONSULTING::
David W. Fanning 
1645 Sheely Drive 
Fort Collins, CO 80526 USA 
Phone: 970-221-0438 <
E-mail: david@idlcoyote.com 
Coyote's Guide to IDL Programming: http://www.idlcoyote.com
History
Written by David W. Fanning, 7 November 2011.
Added a BACKGROUND keyword. 31 Aug 2012. DWF.
Copyright
Copyright (c) 2011, Fanning Software Consulting, Inc.
e initialization routine for the cgMapContinents object. 
Params
class: out, optional, type=structure
   Occasionally, it is useful to have an object class definition as
   a structure variable. Using this output keyword will allow that.
Keywords
background: in, optional, type=string
   The name of the background color. A polygon of this color is drawn
   in the map space set up by the map projection before continents and
   other items are drawn.
coasts: in, optional, type=boolean, default=0
   Set this keyword if you want coasts to be drawn. This keyword is ignored if using FILENAME.
color: in, optional, type=string, default='opposite'
   The name of the drawing color for the program.
continents: in, optional, type=boolean  
   Set this keyword if you want continental outlines to be drawn. This will be
   set automatically if COASTS, COUNTRIES, RIVERS, AND USA keywords are all set
   to zero. This keyword is ignored if using FILENAME.
filename: in, optional, type=string
   The name of the GSHHS file to open. If a fully qualified file name is not provided,
   the program will look for the GSHHS file using cgFindPathTo() function. Only if
   this fails and a file is not found, will an error be issued. This keyword applies only
   to GSHHS data files currently. If the GSHHS keyword is set, and this keyword is undefined,
   then the filename will be set to "gshhs_i.b", unless the HIRES keyword is set, in which
   case it will be set to "gshhs_h.b."
fill: in, optional, type=boolean, default=0
   Set this keyword to draw filled polygons rather than outlines.
gshhs: in, optional, type=boolean, default=0
   Set this keyword to indicate you want to draw continents with the GSHHS data set.
   Using the FILENAME keyword automatically sets this keyword.
hires: in, optional, type=boolean, default=0
   Set this keyword to use the high-resolution data supplied with IDL for MAP_CONTINENTS.
   This keyword is ignored if using FILENAME.
land_color: in, optional, type=string, default='tan8'         
   The name of a color to be used for "land". Used when the FILL keyword is set.
level: in, optional, type=integer, default=2  
   The polygon LEVEL. All polygons less than or equal to this value
   are drawn. 1-land, 2-lakes, 3-island in lake, 4-pond in island.
   This keyword applies only to GSHHS data sets.
linestyle:  in, optional, type=integer, default=0
   Set to the type of linestyle in drawing outlines. Set solid lines by default.
minarea: in, optional, type=float, default=500 km^2
   The minimum feature area. By default, 500 km^2. Polygons with areas less
   than this are not drawn. This keyword applies only to GSHHS data sets.
outline: in, optional, type=boolean, default=0
   Set this keyword to draw shorelines. Set by default if FILL=0. This keyword applies 
   only to GSHHS data sets.
rivers: in, optional, type=boolean, default=0  
   Set this keyword if you wish to draw rivers. This keyword is ignored if using FILENAME.
t3d: in, optional, type=boolean, default=0  
   Set this graphics keyword if you wish to draw outlines use the T3D transformation matrix.
   This keyword is ignored if using FILENAME.
thick: in, optional, type=integer, default=1
   Set this keyword to the thickness of the lines that are drawn.
usa: in, optional, type=boolean, default=0  
   Set this keyword if you wish do draw United States state boundaries. This keyword is 
   ignored if using FILENAME.
water_color: in, optional, type=string, default='sky blue'
   The name of the water color. This keyword applies only to GSHHS data sets.
zvalue: in, optional, type=float, default=0.0  
   Set this keyword to the ZVALUE where the outlines should be drawn. Set to 0 by default.
   This keyword is ignored if using FILENAME.
is method is the clean-up method for the object.
is is the class definition module. Structures used to manipulate
p projection information are also created here.