Pitney Bowes MapXtreme - Manual (Page 277)

Chapter 14: Using Themes and Legends
RangedTheme
MapXtreme v7.1 284 Developer Guide
Controlling Display Size for Pie and Bar Themes
MapXtreme provides the abstract base class MultiVariableTheme that supports the creation of pie
and bar object themes. This class, derived from the ObjectTheme class, provides two properties,
DataValueAtSize and Size, that control how large object theme geometries display at particular
values. The default value for DataValueAtSize is set to the largest data value of the mapped
features. The Size value controls the width of pie charts and the height of bar charts in paper units.
RangedTheme
A ranged theme shows data grouped into ranges (bins) according to specific criteria. In MapXtreme
a ranged theme modifies an existing layer to reflect that criteria. It does not create a new layer, as
range themes did in previous versions of MapX and MapXtreme. When you create a ranged
thematic map, MapXtreme groups all dataset rows into ranges and assigns each row’s object the
color, symbol, or line for its corresponding range.
Example of a ranged thematic map.
When To Use a Ranged Theme
A ranged theme is useful, for example, when you have demographic data for an area. For example,
rural male population in Asia can be grouped into bins and shaded by color to indicate the population
ranges that exist across the area.
All records in the dataset are assigned to a range and then drawn with a style based on that range.
When using a yellow to green color range, for example, the countries with the highest population
could be shaded yellow, the lowest shaded green and the intermediate ranges some color in
between yellow and green. When the map is displayed, the colors make it readily apparent where
the highest and lowest populations exist. (See
How to Apply Translucent Effects to Themes for
instructions on applying translucency effects to a ranged thematic map.)
Ranges are also useful when the size of the region is not directly related to the magnitude of the
data values.