How to use geospatial components

The core module relies on the following basic
geospatial concepts:

• Geocoordinates are WGS-84 coordinates expressed in decimal degrees and,
  latitude and longitude pairs, in this order. Valid values are between -90 and
  90, and -180 and 180.

• A line string is an ordered sequence of geocoordinates (a
  polygonal chain) that you can
  use, for example, to represent the shape of a road segment.

• The Location Library uses a fraction to represent the position of a point
  M on a line string starting at a point P. The fraction is the ratio of the
  length of the partial line string PM to the length of the full line string.

  Note

  In the Location Library, all distances are displayed and calculated in
  meters (m).

  In the example below, the total length of the line string is 400m (100 +
  75 + 50 + 75 + 100), the length of the partial line string PM is 205m
  (100 + 75 + 30). So the fraction representing the position of M on the line
  string is 0.5125 (205 / 400).

  
  Figure: The fraction representing the position of M on the line string is 0.5125

  Note

  The Location Library uses fractions to specify sections of a line string on
  which a property applies. For more information, see
  RangeBasedPropertyMap.

• A bounding box in the Location Library is defined using geocoordinates.

• Coordinates are (projected) two-dimensional Cartesian coordinates. You can
  use coordinates to simplify distance calculations. As a consequence, many
  components of the Location Library, including proximity search and map
  matching, use coordinates internally.

• A geo-projection
  (map projection) is a
  transformation from geocoordinates to coordinates. The
  GeoProjection
  interface allows you to specify the desired projection. Currently, the
  Location Library provides one fast and reasonably accurate geographical
  projection, the
  sinusoidal projection
  that returns a locally flattened approximation of the Earth's surface around
  the provided center. This approximation has an error that is less than 1% for
  distances up to 10 km when the latitude is between +85 and -85 degrees.

  Note

  Geo-projection introduces distance and angle distortions, which can limit
  the accuracy of calculations using it. To ensure precision, do not use
  coordinates that are too close to the poles or too far away from each other.