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CGGOOGLEMAPWIDGET

CGGOOGLEMAPWIDGET
  This is the driver for the cgGoogleMapWidget object, which is a compound widget
  object that obtains a Google static map from Google Maps and displays it in the
  program's draw widget window. It can be used either as a stand-alone program or
  to create a map image in draw widget in a larger widget program.
  This program implements a subset of the Google Static Map API, which can be found in
  more detail here: https://developers.google.com/maps/documentation/staticmaps/. The
  program works by building a URL for a map image. A connection to the Internet is
  required to then request a map image (in GIF, JPEG or PNG format) to be returned from
  Google Maps. The returned image is then read and loaded into a draw widget window
  of the right size for the returned map image. The default is to delete the image file
  that is created, but the user can also set keywords to retain the image that is downloaded
  from Google Maps. Users are able to control button and motion events in the resulting
  draw widget with their own event handler module. A cgMap coordinate object is created
  to establish a map reference coordinate system on top of the returned map image, allowing
  other map information to be drawn on top of the returned map image.

Categories


    Graphics, Widgets
   

Params


    parent: in, optional, type=long
        The identifier of the parent widget of the draw widget that is going to be
        created by the program. If not provided, the program will create its own
        top-level base widget as the parent.
     

Keywords


    box_axes: in, optional, type=boolean, default=0
        Set this keyword to draw box axes around the Google Map.
    button_events: in, optional, type=boolean, default=0
        Set this keyword to turn button events on for the draw widget in the program.
    center_latitude: in, optional, type=float, default=40.60
        The center latitude of the requested Google map. If not provided, the latitude of
        Fort Collins, Colorado, home of Coyote. Latitudes are only recognized to four
        decimals values of precision.
    center_longitude: in, optional, type=float, default=-105.10
        The center longitude of the requested Google map. If not provided, the longitude of
        Fort Collins, Colorado, home of Coyote. Longitude are only recognized to four
        decimals values of precision.
    event_method: in, optional, type='string'
        The name of the event handler method for the draw widget. If you use this keyword,
        you will also need to write this event handler module. It gets sent one positional
        parameter, the event structure created by the draw widget.
    event_pro: in, optional, type='string'
        The name of an external event handler procedure for the draw widget. The event handler
        procedure gets sent one positional parameter, the event structure created by the draw widget.
    imagetype: in, optional, type=string, default='png32'
        The type of image format the Google map should be returned in. The default is
        a 32-bit full color PNG file. The image types are given in the Google Static Map
        API documentation and are as follows: png or png8, png32, gif, jpg, and jpg-baseline.
    keep_image: in, optional, type=boolean, default=0
        Set this keyword if you wish to save the Google map as an image when the object
        is destroyed.
    maptype: in, optional, type=string, default='terrain'
        Set this keyword to the type of map you wish to retrieve from Google Maps. The
        choices are listed in the Google Static Map API documentation and are: "roadmap",
        "terrain", "satellite", and "hybrid".
    markers: in, optional, type=structure
        A scalar or array of cgGoogleMapMarker structures. If present, the markers will
        be requested with the map from Google. The cgGoogleMapMarker structure is defined
        like this::
            struct = { cgGOOGLEMAPMARKER, $
              size: "", $ ; The marker size ("tiny", "small", "mid" or "normal")
              color: "", $ ; A color name as provided by cgColor.
              label: "", $ ; A single uppercase character label from the set {A-Z,0-9}.
              lats: Ptr_New(), $ ; A pointer to one or more latitude values.
              lons: Ptr_New() } ; A pointer to one or more longitude values.
        Note that the user will be responsible for freeing the pointers in the MARKERS
        structure. This program will not do that.
    motion_events: in, optional, type=boolean, default=0
        Set this keyword to turn motion events on for the draw widget in the program.
    tempDir: in, optional, type=string
        The directory where the image containing the Google map is written. By default,
        it is obtained from the environment like this: tempdir = GetEnv('IDL_TMPDIR').
    visiblemarkers: in, optional, type=boolean, default=1
        Set this keyword to 0 to temporarily turn off the display of the markers. Normally,
        markers are drawn (if present), unless this flag is set to 0.
    xsize: in, optional, type=int, default=600
        The X size of the program's draw widget. A maximum of 690 if box axes are requested
        and a maximum of 640 if no box axes are requested. Box axes require a 25 pixel border
        and the maximum size of a Google Map is 640 pixels.
    ysize: in, optional, type=int, default=600
        The Y size of the program's draw widget. A maximum of 690 if box axes are requested
        and a maximum of 640 if no box axes are requested. Box axes require a 25 pixel border
        and the maximum size of a Google Map is 640 pixels.
    zoomlevel: in, optional, type=integer, default=12
        The zoom level of the requested Google map. Should be an integer between 0 and 21.

Returns


    The return value is an instance of a cgGoogleMapWidget object.
   

Examples


    Used to put two markers on a map of Fort Collins, Colorado, in a stand-alone window::
        PRO cgGoogleMapWidget_Test
            marker1 = {cgGOOGLEMAPMARKER, 'normal', 'dodger blue', 'A', Ptr_New(40.600), Ptr_New(-105.100)}
            marker2 = {cgGOOGLEMAPMARKER, 'normal', 'purple', 'B', Ptr_New(40.605), Ptr_New(-105.105)}
            googleObject = cgGoogleMapWidget(MARKERS=[marker1, marker2], MAPTYPE='Terrain')
        END
     

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


    Change History::
        Written, 25 June 2012. DWF.

Copyright


    Copyright (c) 2012, Fanning Software Consulting, Inc.



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