Copyright © 2002-2008 Open Geospatial Consortium, Inc. All Rights Reserved.
23 SearchCentreDistance N
Float decimal metres
Distance of Point from starting Position.
Notes:
1. SearchArea must contain starting Position; therefore the service must be capable of validating this.
2. All response lists are sorted in order of shortest to longest SearchCentreDistance default in metres.
3. If SearchArea is not specified, only the nearest valid response is returned.
15.4 Part 4: Presentation Service
This service renders geographic information for display on a Mobile Terminal. Any OpenLS Application may call upon this service to obtain a map of a desired area, with or
without map overlays that depict one or more OpenLS ADTs, such as Route Geometry, Point of Interest, Area of Interest, Location, Position andor Address. The service may
also be employed to render route directions from Route Maneuver List ADT andor Route Instructions List ADT.
15.4.1.1
Output Parameters
Defines what the size and encoding of the portrayed map should be using the following criteria:
Width – The width of the map in pixels. Height – The height of the map in pixels.
Format – Parameter that specifies what the encoding of the map should
be. This is specified as a mime-type. The mime-types supported are left up to the implementation.
Transparency - Boolean that defines the opacity of the background of the
map.
Background Color – Defines the background color of a map if it is
opaque.
Content – Specifies what type of content would be returned, whether the
URL or the data as base64
Copyright © 2002-2008 Open Geospatial Consortium, Inc. All Rights Reserved.
24 The default behavior of the map is to return the exact image size as specified in the
request. The Harmonization group is working on harmonizing the different OGC Standards such as WMS and OpenLS, to have consistent behavior where both specs are
concerned.
15.4.1.2
Context Defines what area of the world the map is portraying. This can be defined in the
following ways:
Bounding Box- Two-point box in a specific SRS that defines the
extents of the map WGS 84 is the default. This is the same bounding box used in WMS and is present for compatibility with
it.
Center Point and Scale - The center point defines the center of your map at a particular scale and projection.
o
Center Point – The center point of the map. This point is
specified in WGS 84 as a latitudelongitude in decimal format.
o
Scale – The ratio between device units and world units.
Specified as the number of world units per device units. Thus 1:50000 would be expressed as a scale of 50000.
o
Azimuth – The orientation of the map. This is expressed
in clockwise degrees from north. o
DPI – Dots per inch of the device.
o
SRS – Spatial Reference System. Provides what projection
should be used when creating the map. o
DisplayScale - A ratio of distance. For example 1:5000
would be expressed as 5000, its always expressed per 1 pixel of the display.
If context is not specified the implementation must derive it from the ADTs.
15.4.1.3
Overlays
Defines a list of ADTs for portrayal on the map.
ADT Abstract Data Type – ADTs are usually obtained as outputs from
other core services. To date we have Position ADT, Route ADT, POI ADT and Map ADT.
