Autodesk 15606-011408-9330 User Guide - Page 95

Map Features Map features are the geographic features that appear on a map. In Autodesk MapGuide, map features are points, such as fire hydrants and cities, polylines, such as rivers and roads, and polygons, such as lakes and land parcels. Each map feature has a name, an optional URL link, and geometric data specified by one or more coordinate pairs. The files containing the spatial data can also contain compound map features, such as polypolylines and polypolygons. Polypolylines are multiple polylines grouped as one to represent compound line features, such as road networks and river systems. Polypolygons represent compound area features, such as islands in a lake. The following sections describe each of the types of map features you might have in your Spatial Data Files. Points A point is single place on a map, such as a telephone pole, or a city. Every point corresponds to a single coordinate pair that locates the point's symbol or text on the map. To use the points from a Spatial Data File in a map, you create a point layer. Lines/Polylines/Polypolylines A line represents a linear feature, such as a street, river, or sewer pipe. A polyline is simply a line with multiple segments, such as a winding road. A polypolyline is a single feature that includes two or more polylines; this is a convenient way to group related polylines into one map feature so that they can be selected or linked to a database as a single entity. The starting point and the ending point of each line segment in a line, polyline, or polypolyline has a coordinate pair, so that a polyline with several line segments, for example, will have several coordinate pairs that define the polyline. Autodesk MapGuide treats lines, polylines, and polypolylines the same way-to use the lines, polylines, and polypolylines from a Spatial Data File in a map, you create a polyline layer. Working with Spatial Data | 95