Documentation | Help File | UI | 2D Mode | Menu | Tools | Topology | Topology
Clicking on the Tools/Topology
menu item invokes the Topology builder and corrector
dialog box used to set up the topology correction task. The Topology builder and corrector
feature are capable of analyzing and correcting the topological properties of both the line and polygon type layers. As a result, a topology project is created consisting of the corrected layer and, optionally, report layers each representing the result of a different stage of the topology analysis. The Topology builder and corrector
feature are capable of detecting the following types of topology elements and errors:
Name | Example (red) | Description |
---|---|---|
intersection | ![]() | A point, where the segments of two lines cross. |
dangling node | ![]() | Vertex connected with one line segment. |
connecting node | ![]() | Vertex connected with two line segments. |
node with 3+ edges | ![]() | Vertex connected with more than two line segments. |
line 0 connected | ![]() | Line containing two dangling nodes and any number of connecting nodes. |
line 1 connected | ![]() | Line containing one dangling node, one node with 3+ edges and any number of connecting nodes |
line 2 connected | ![]() | Line containing two nodes with 3+ edges and any number of connecting nodes. |
Name | Example (red) | Description |
---|---|---|
centroid | ![]() | Center point of a polygon; a centroid is always forced to lay within its polygon. |
intersection | ![]() | A point where two segments of some polygons outlines cross. |
correct polygon | ![]() | A polygon that has no topology errors. |
overlap | ![]() | A polygon covering the area, where at least two polygons overlap. |
hole | ![]() | A polygon covering the area, where at least two touching polygons outlines branch off and touch again afterwards; also, a polygon internal hole |
edge | ![]() | A polygon outline that is topologically correct. |
dangling edge | ![]() | An element of the polygon outline that gives no contribution to the polygon area. |
external border | ![]() | If all the polygons in a layer are touching forming one “island”, the outline of that “island”; otherwise, the outline of the leftmost “island” |
To build a topology project for a vector layer
Tools/Topology
menu item - this invokes the Topology builder and corrector
dialog box.Topology builder and corrector
dialog box set the name and path of the topology project file. First, click on the […]
button in the Output project file
field- this invokes the Save As
dialog box.Save As
dialog box go to the drive on which you want to store the project file.File name
field.Save
button - this brings back the Topology builder and corrector
dialog box.Topology builder and corrector
feature can analyze only one type of shapes at a time. If the layer to be analyzed contains more than one type of shapes, e.g. lines and polygons, then select the appropriate shape type in the Input type.Topology type
box.Additional layers
list choose which additional layers should be added to the topology project - see Additional layers
below.Input type feature
is set to Lines
and the Topology type
is set to Linear
, the Linear topology options
become available and can be used. For detailed information see Linear topology options
below.Tolerance (layer units)
field set the tolerance used for topology correction; if zero, the topology correction is not performed.OK
button - the Progress…
message box will appear informing about the progress of the topology analysis.OK
button.OK
button to open the result of the topology analysis.
The following additional layers can be added to the topology project: