How to digitize a line?
October 8, 2011 Leave a comment
If you wish to have the length computed for a section of a road, a river, or a property boundary, you must first digitize it into a Line Feature. A Line Feature is a vector shape and can be saved in the shapefile format.
To digitize a Line Feature in iCMTGIS or iGPSGIS, first select an existing Lin Topic or create a new Line Topic.
To create a new Line Topic, tap the Main Menu, select Topic then select New Topic. Enter a Topic Name, such as “Path”. Make sure the Type field shows: Line. Tap the green check mark to confirm the screen and return to the Map View.
To activate an existing Line Topic in order to add a new Line Feature to this group, tap the Topic View icon on the upper-right corner of the main screen then select the desired Line Topic. Tap the Topic View icon again to hide the list of Topics.
When a Line Topic is active, and you tap the pull-down arrow for the Tools icon next to the Main Menu icon, you will see that the Add Line manually tool is active (not grayed out). Tap this selection, and the Add Line manually tool icon will be displayed.
Now, tap to drop nodes along the line or drag to trace the curvilinear line.
While you are digitizing, if you need to zoom in or out, first tap on the little hand with a pointed index finger. This will halt the digitization mode and reactivate the regular touch-screen mode. Tap on this toggle again when you are ready to continue with the digitization.
If there are existing Features on the map and you want a node to snap to one of the existing Features, then tap the SnapTo Node tool showing an arrow pointing to a node. When the SnapTo Node toggle is on, the node you add will be dropped on top of the nearest Point or node.
When you have digitized the last node for the Line Feature, tap the Add Line manually tool again to turn this function off.