When assigning labels to objects in a GIS layer—whether the layer contains points, lines, or polygons—XMap’s integrated cartographic engine optimizes the placement of the labels to ensure the clearest possible text display while maintaining the aesthetic qualities of the map. Polygon labels are automatically placed at the geometric center of the object being labeled; point labels are, by default, positioned above and to the right of the symbol; and line labels are placed as close as possible to the mid-point of the line. If necessary, XMap uses a text decluttering process to ensure that one label does not overlay another.
In most cases, this automated labeling process is sufficient to clearly denote the required information about the object; however, cartographic sticklers will suggest that a perfect map cannot be created without some sort of human input. By following a few simple and creative steps, it is possible to fine-tune or tweak the positioning of labels in XMap while providing the opportunity to determine the zoom level range within which labels appear.
The first step in this process is to create a duplicate copy of the layer in question. To do this, first select the layer in the Workspace, click Layers, click Create, and then click Copy Layer. It is a good idea to add “Labels” to the name of this second layer.
Next, adjust the symbolization of this new labels layer so that the objects on the map are transparent or invisible. The Symbolize dialog box can be accessed by right-clicking the layer in the Workspace or by clicking the Tools button above the Workspace table and selecting Symbolize. For each color or class displayed in the Symbolization window, change the Opacity setting to Transparent, then click OK. The objects formerly displayed on the map will disappear.
You can now use the Label function, accessed from the Tools menu, to add the required labels to this transparent layer. Although the objects are not visible, the labels will appear on the map.
Initially, these labels will appear in the same location as if the original layer had been labeled; however, because the objects to which they are assigned are invisible, their position can be moved without affecting the appearance of the map. To move these labels, select the new labels layer from the Active Layer dropdown list in the toolbar and click the Edit tool to the right. Each label can be individually selected and moved as needed.
With the labels for the original layer now contained within a second layer, it is possible to more precisely control the appearance and behavior of these labels. To customize the settings for this layer, click the Tools button and select Properties. Within this dialog box are options for determining whether the labels appear in the Primary and/or Secondary Maps, for setting the Zoom Level range at which the labels appear, and for adjusting the layering hierarchy to ensure that the labels are displayed on top of the objects in the original layer.
With a little creativity, it is possible to create a map that not only uses the latest in cartographic technology but also allows a certain amount of individual input.
