Autodesk 15606-011408-9320 User Guide - Page 108

Differences in Clipping VISION* supports a clipping primitive that is occasionally used to avoid drawing in areas where annotations might later be drawn. For example, when labeling a line, a clip area might be defined over the area where the label will appear, creating a gap where the label will be drawn. Although lines will be clipped by such a region, PostScript and TrueType fonts and polygons will not be clipped. Therefore, some maps might display differently in Autodesk MapGuide. Primitives and Styles Simulated Using Polylines To account for feature geometry and style model differences between VISION* and Autodesk MapGuide, several primitives and styles will be simulated in Autodesk MapGuide using polylines. Scale-Dependent Symbology Displayed as Fixed Some scale-dependent VISION* symbology (for example, line thickness) is displayed in Autodesk MapGuide at a fixed scale. In this case, the scale will be correct when the symbology is initially displayed in Autodesk MapGuide, but as the user zooms, the lines will not get thicker. Polygons Obscuring Non-Polygons When a map has two or more VISION* theme layers, and the themes contain features composed of polygon primitives and other feature types such as annotations, some of the polygon primitives from the upper layers may obscure the non-polygonal features and annotation from the lower layers. You can reconstruct your VISION* cache using separate themes for polygons and other feature types such as annotations, which will allow you to display the polygons separately on a layer lower in the display order than the annotation layer. You need to plan the display order of layers carefully, in order to minimize the effect of features from upper layers obscuring those on lower layers. 108 | Chapter 5 Working with Data in Autodesk MapGuide