2. GIS data entry
2.5 Edit Existing Layer
Level of expertise required for this Chapter: Beginner; general Map Maker training
To edit a layer (polygon, line, point, or text), it has to be in live layer mode. There are various ways to insert a layer (or file) into the live layer:
A) Right-mouse > Project manager > Add layer > Choose file window: Select folder, file type, file > Open > Copy layer to live layer, or:
B) Main menu > Edit > Load file into live layer > Choose file window: Select folder, file type, file > Open, or:
C) At the project bar on the left side, next to the tools, there is a small blue round button > Load file into live layer > Choose file window: Select folder, file type, file > Open
You can add various layers at the same time to the live layer, thus combining them.
Most of this manual will explain the procedures to edit maps in live layer mode.
Fast access to many (though not all) tools for editing are in the tool bar on the left side. There are the Polygon-tool, Line-tool, Symbol-tool, Cutter-tool etc, see below.
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To edit the main characteristics of a feature, you click on the Edit-tool on the toolbar left (or alternatively, right-mouse > Edit > Edit object), then select the unit, by:
A) Single-click will bring you to a window with four tabs: Basics, Styles, Data and Actions (see below).
At the first tab (‘Basics’) you can enter or change the display label, at the second the style. These are the two main data directly associated with each feature. (Unlimited additional data are stored in the associated database file, see Chapter 4).
The actions listed at the last tab depend of the type of the edited feature (polygon, line or point).
B) Double-click will bring you to the vertex editing mode, where you can change the vertex (position). You will see the cursor change to a circle, when you move over a vertex point. By left-click, you can drag (move) or delete this point.
By right-click, you get to the Edit vertex window (see below) with additional actions for this vertex point.
After finished editing, don’t forget to save the edited layer. Map Maker writes two files for these types of vector files: One DRA file (with the topology and all coordinates) and one DBF file (for the attached database):
Right-mouse > Save live layer as… > Select folder > Specify (or confirm) file name.
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Note: If you want to digitize a line, which is a common boundary to two polygons, you select the Edit-tool and click on the common boundary without double-clicking on the unit first.
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If you don’t want to save: Main menu > Edit > Clear live layer
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LUPMIS exercise: Bring layer Ghana_regions to the live layer, save it under a temporary name (Temp), call this temporary layer back to live layer, and edit boundaries in this layer.