Pitney Bowes MapXtreme - Manual (Page 64)

Chapter 3: Mapping Concepts
Geocoding with MapXtreme
MapXtreme v7.1 64 Developer Guide
A projection is a method of reducing the distortion that occurs when objects from a spherical surface
are displayed on a flat surface. There are two main trade-offs to be considered: the preservation of
equal area, and the preservation of the true shape of a feature. There are many different types of
projections, each designed to reduce the amount of distortion for a given area. Some projections
preserve shape; others preserve accuracy of area, distance, or direction.
A coordinate system is a set of parameters that tells you how to interpret the locational coordinates
for objects. One of those parameters is projection. Coordinates can be of two types: Spherical or
Cartesian. Spherical relates to locations on the curved surface of the Earth, while Cartesian
describes flat surface locations in two dimensions. Both are represented by x and y coordinates. The
difference comes when calculating distance or area of features that represent real Earth locations
such as streets or rivers (Spherical), or relative locations, such as a map of brain anatomy or a chess
board (Cartesian).
Knowing which coordinate system your map uses is an important consideration when developing
applications. Analytical operations involving distance and area calculations, such as buffering,
routing, and querying use the coordinate system and projection to yield the correct results.
Coordinate system and projection classes are part of the MapInfo.Geometry namespace. For more
information see
Chapter 16: Spatial Objects and Coordinate Systems .
Geocoding with MapXtreme
The maps discussed above all use data that provide additional information beyond what you can see
on the map. For example, a table of store locations not only includes geographic coordinates to
place the stores in the correct map location, it may contain data about the locations, such as store
hours, customer service phone numbers and manager name. This gives the application the power to
analyze and yield information that would otherwise be lost in rows and columns of tables.
Typically a table of custom data is included on a map along with reference layers, such as streets,
town boundaries and water features that represent the true environment of the area. These
references layers are usually purchased ready to display on a map. Pitney Bowes Software sells a
wide variety of reference data for locations around the world. Additionally, MapXtreme provides
more than 400 MB of sample data for world locations. To install, from the MapXtreme product CD
browser, choose Install Sample Data. Use the Custom installation option to install as much of this
data set that you need.
But the custom data, like your store locations or call center regions, may not be ready to display on a
map. The table must contain geographic coordinates so the mapping engine knows where to draw
the objects. The process of assigning coordinates to data is called geocoding. Any table of data that
contains locational information, such as address or postal code, can be geocoded. The process
involves matching the custom table against an already geocoded table covering the same location. If
an address match is made, the coordinates from the geocoded table are assigned to the custom
data. Then the custom data is ready to be viewed on a map.
Geocoding is a typical early step in the process of creating a map. As a developer of mapping
applications, you will need to consider the type of data you wish to display on the map and its need
to be geocoded.