Pitney Bowes MapXtreme - Manual (Page 429)

Chapter 23: Workspace Manager
Layer Control
MapXtreme v7.1 436 Developer Guide
For example, suppose you are configuring the labels for the WorldCapitals layer, which contains
point features that represent cities. You probably want the cities with the largest population to have
the highest labeling priority. In this case, you would specify a labeling expression such as:
cap_pop
The cap_pop column represents the population of each capital city. When you specify a Per-Label
Priority Expression of cap_pop, you are specifying that the cities with the largest population should
have the highest labeling priority. As a result, the most populous cities will be labeled first, while
other cities will be labeled only if there is enough room left over.
Per-Table Priority Expression This expression field is optional. A label layer can contain multiple
label sources; for example, you might have one label source representing a set of labels for World
Countries, and another label source representing a set of labels for World Capitals (cities). By
default, the label source at the top of the list has the highest priority. If you want to assign a higher
priority to a label source, you can either move that label source up (in the layer control’s list of label
sources), or you can specify a Per-Table Priority Expression for each label source.
For example, if you give the World Countries label source a per-table priority expression of 10, and
give the World Capitals label source a per-table priority expression of 5, country labels will have
priority over capital city labels.
Group Layer Settings
Highlight the Group Layer node in Layer Control and a Visibility tab displays. Here you control
visibility settings that apply to all layers in the group.
To apply different visibility settings to each layer in the group, highlight the layer that is shown under
the Group Layer and make the changes in the Visibility tab that displays.
Style Override Settings
When you highlight a style override layer in Layer Control, the Visibility tab displays. Here you
control whether the style override is visible and at what zoom range. The Style buttons are
accessible here for you to set the area, line, symbol and text styles for the layer.
Choose from two drawing modes: Normal and Superimpose. Normal drawing mode draws the
layer using the style override. Superimpose draws the style override on top of the layer.
Graticule Layer Settings
When you click on a graticule layer, the following tabs are available at the bottom of the Layer
Control.