====== About MapObjects ======

''MapObjects'' are used by the Viewer SDK to convey what should be rendered on the Reference Map in your host environment, and do this in a generic way to simplify the implementation.  The Viewer SDK will return MapObject instances for e.g. : 
  * Measurement results
  * Field-of-view indicators
  * Resource footprints
  * ...

===== MapObject Types =====

Each MapObject has a ''type'' property.  MapObject types are used to group MapObjects that are related and should be rendered in the same layer.  

===== Coordinate System =====

The Viewer has a central setting that determines the [[glossary|CRS]] of any spatial data returned by the Viewer API.  By default, this settings is set to 4326 (WGS/84).  It can be customized by providing the Constants.STARTUP_CRS [[glossary|startup option]].

This setting also affects the CRS of all returned MapObject instances.

===== Rendering =====

Rendering MapObject instances is essential to implementing a good plugin.  Write a //generic// function that handles rendering a list of MapObject instances into a third-party map layer. This function will be re-used in different places.

==== Rendering Lines ====

The ''spatialLine'' property is a CoordinatePath instance containing one or more CoordinateLine instances.  Each CoordinateLine instance holds a list of Coordinate instances defining the outline of a single line.

Legend properties : 
  * color : the outline color.
  * lineWidth : the outline width in 96dpi pixels.

==== Rendering Areas ====

The ''spatialArea'' property is a CoordinatePath instance containing one or more CoordinateLine instances.  Each CoordinateLine instance holds a list of Coordinate instances defining the outline of a single area.

Legend properties : 
  * color : the outline color.
  * lineWidth : the outline width in 96dpi pixels.
  * fillColor : the fill color.

==== Rendering Points ====

The ''spatialPoint'' property is a symbol at a specific coordinate.

Legend properties : 
  * symbolName : the name of a preset symbol.
  * symbolPath : the path of a symbol.
  * symbolSize : the size of the symbol in 96dpi pixels.
  * color : the symbol outline color.
  * lineWidth : the symbol outline width in 96dpi pixels.
  * fillColor : the symbol fill color.

The symbol is to be rendered inside a square with size ''symbolSize''.  The center of the square should be placed on the coordinate defined by ''spatialPoint''.

Possible symbolName values : 
  * ''circle'' : a filled circle.