The following workflows use the Black Mountain Lake.gmw file which was saved at the end of the Drawing Points, Lines, and Polygons topic.
When working with vector data, it is not uncommon to find problems with the shape or alignment of the features when compared to other data layers. Global Mapper provides an array of tools for editing or updating the location and structure of points, lines, and polygons, and we will be introducing some of these in this lesson.
Edits can be applied to features that have been drawn in Global Mapper as well as features contained in imported layers. When updating an imported layer, the changes are saved within the Global Mapper workspace and are not automatically applied to the external layer.
Editing the Location of the Feature
Perhaps the simplest edit that can be applied to a selected vector feature is to move it to a new location. This can be done by defining the required offset in terms of distance and bearing or, as we will see in this exercise, by selecting the feature and dragging it. As we begin the process of editing, we will also introduce the option of rotating and scaling a polygon.
In Global Mapper, load the previously saved Black Mountain Lake.gmw workspace from your My Maps folder and follow along as the instructor demonstrates some of the feature editing functionality.
To streamline the process of moving a point, line, or polygon, hold the Alt key on your keyboard while selecting the feature, and the cursor will be automatically in move mode.
Editing the Structure of the Feature
The actions of moving and rotating maintain the structure of the feature while simply placing it in a new location. As we further explore Global Mapper’s vector editing tools, we will introduce the idea of reshaping the polygon. Following on from the previous exercise, we will first enable the display of the vertices before performing a number of vertex-specific edits including adding, deleting, and moving vertices.
Using the Black Mountain Lake.gmw file, follow along with this video as the instructor demonstrates editing the structure of a vector feature.
Global Mapper’s Favorites toolbar can be used to create a list of commonly-used tools, providing a quick and easy way to assess the functionality that is most important for your workflows.
Editing the Feature Settings
During the Introduction to the Digitizer, we discussed Modify Feature Info dialog box and the important role it plays in the process of creating points, lines, and polygons. As we saw in the first exercise, it appears automatically at the end of the drawing process allowing the assignment of a target layer, Feature Type, and other settings. This dialog box is also applicable to existing features allowing the aforementioned settings to be updated or edited. In the final workflow of this lesson, we will change some of the settings that were applied to the lake polygon.
Follow these steps as we create a label for the lake polygon and apply a more relevant Feature Type.
- If necessary, open the Black Mountain Lake.gmw workspace from your My Maps folder.
- Use the Alt + D keyboard shortcut to activate the Digitizer.
- On the map, click on the lake polygon to select it.
- Right-click and choose EDIT – Edit Area Feature.
- In the Name field, type “Lake Tomahawk“.
- From the Feature Type dropdown list, choose Lake, Unknown Area.
- Click the OK button and use the ESC keyboard key to deselect the polygon.
- Use the Ctrl + S keyboard shortcut to save the workspace.
Always make sure to create or save a workspace file when you finish any editing process.
- Global Mapper’s vector editing tools can be used to realign and restructure points, lines, and polygons.
- Editing the shape of a polygon or line requires the display and selection of vertices for the relevant features.
- The workspace records the path to the original data as well as the edits that have been applied.
- Click here for more information on editing the shape and position of vector features.
This concludes the Using the Digitizer lesson. See how much you remember by taking this three-question quiz.