GMS:Build Polygons Workflow

Polygons can be created in GMS with the following steps:

1. Create enclosed arcs for polygon areas.

1. Create feature points, arcs, nodes and vertices. In the map module, create feature objects in the active coverage. Use the Create Arc tool to create arcs in the map coverage. Begin creating a new arc by clicking in the graphics window at either arc end. If clicking on an existing feature node, vertex or arc, the new arc will snap to that object. Double-click or press the Enter key to terminate the arc. Use the Create Point tool to create additional nodes alone or to split arcs. 2. Modify arcs. Feature arcs, whether digitized or incorporated from a boundary condition or a material coverage, often need to be edited after initial creation. 1. Create additional vertices on arcs. Use the Create Vertex tool to add vertices along arcs. 2. Refine the arc shape. Use the Select Vertices tool and the Select Points\Nodes tool to move/edit existing arcs and refine the shape by dragging the nodes/vertices. Use the Select Arcs tool to move entire arcs . 3. Split arcs. An existing arc can be split by: 1. Converting a vertex to a node. Use the Select Vertices tool. Select the Feature Objects | Vertices → Nodes command to split the arc into two arcs. 2. Add a node to the arc. Use the Create Point tool to add a node on an arc in order to split it into two arcs. 3. Connect the end of an existing arc to the middle of the arc. Use the Select Points\Nodes tool to drag the node of an existing arc to anywhere in the middle of another arc. This will split the second arc into two arcs. 4. Add a new connecting arc. Use the Create Arc tool to start or end a new arc on an existing arc to split the existing arc into two arcs. 5. Split overlapping arcs using the Clean Options dialog. Select overlapping arcs using the Select Arcs tool. Use the Feature Objects | Clean command to bring up the Clean Options dialog. Select the Intersect selected arcs option (for selected arcs) or Intersect arcs option (for all overlapping arcs) to split the arcs. 4. Merge arcs. Two arcs that share an end node can be merged together. Select the shared node using the Select Points\Nodes tool. Click on the Feature Objects | Nodes → Vertices menu command to merge the arcs. If desired, the Select Vertices tool can be used to select and delete the new vertex. 5. Transform arcs. Select the arc using the Select Arcs tool. Use the Edit | Transform command. Use the Transform dialog to scale, translate or rotate the arc.

2. Build polygons in enclosed areas.
Polygons are not created automatically when arcs are enclosed. To create polygons: Use the Feature Objects | Build Polygons command.