Pitney Bowes MapXtreme - Manual (Page 274)

Chapter 14: Using Themes and Legends
GraduatedSymbolTheme
MapXtreme v7.1 281 Developer Guide
Example of a Graduated Symbol thematic map.
When To Use a Graduated Symbol Theme
Graduated symbols maps work with numeric data only. It makes no sense to create graduated
symbols based on the type of cuisine each restaurant serves. However, graduated symbols are
appropriate when you want to show the distribution of housing income by city.
VB example:
Public Shared Sub MapInfo_Mapping_Thematics_GraduatedSymbolTheme(ByVal
map As Map)
‘ Load a map based on one table
map.Load(New MapTableLoader(“world.tab”))
Dim lyr As FeatureLayer = CType(map.Layers(“world”), FeatureLayer)
‘ Create a new graduated symbol theme
Dim gradTheme As GraduatedSymbolTheme = New _
GraduatedSymbolTheme(lyr.Table, “Pop_Native”)
‘ Create an object theme layer based on that graduated symbol theme
Dim thmLayer As ObjectThemeLayer = New ObjectThemeLayer(“World Pop _
Growth Rate”, Nothing, gradTheme)
‘Add object theme to the map’s layer collection.
map.Layers.Add(thmLayer)
‘ Adjust how we graduate the size.
gradTheme.GraduateSizeBy = GraduateSizeBy.Constant
thmLayer.RebuildTheme()
End Sub