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Topological cleaning

TRANSLATION NOTES: Please read some comments at the end of this post.

It is called in that way GIS tools action of eliminate vectors inconsistencies to commonly accepted standards in the spatial topology. Each tool has been implemented in their own way; consider the case of Bentley Map and Manifold GIS.

Microstation Geographics


Microstation includes two tools for the same, one activated by keyin (dialog cleanup) and the other known as topology Cleanup. For reasons of dispersion, we all prefer the first although it does not exist for that more than a command button to the former.

Topological includes six topological options in the left frame, while in the bottom are the tolerances and to the right the destination and characteristics which are expected indicative of inconsistency. While it is called topological cleaning, this is not the most appropriate name; rather are vector cleaning tools which includes:

  • Duplicate items.
  • Similar items
  • Thin, it was little used but it is to determine vertexes’ abuse unnecessarily
  • Segmentation.
  • Fragments.
  • Separate components

For almost each one it had the option of choosing the error destination, to mark or remove option and tolerances. It was not bad, even had the mrf tools compiled with mdl allowing navigate through errors. But it used to be a headache as it were, not for cleaning because it was clear but for back utility in the spatial or topological analysis. To take one example, in different map’s layers it was a problem the mismatch nodes, a crazy situation.

Bentley Map


The panel changed with Bentley Map, there is always the Dialog Cleanup but requires having an open project; other alternative was concentrated in a single tabbed panel. Additionally there were added very functional options including:

  • Filter by view control
  • It can be filtered the objects type (line, arc, polyline etc)
  • The match may include line type, color or thickness
  • Create an automatic backup file
  • The overlap can eliminate duplicates
  • You can save the settings as a .rsc file and recall it
  • It was removed the thin, nobody used it because it did not work

It would have to be proven if the headache improves with the topological analysis, as it was too harsh and required too crazy joints accuracy with which the tolerances had no sense. Also the red warning flags are not dynamic vector objects, which makes that much of the work becomes a visual skill rather than a dynamic size cell.

Manifold GIS


Bentley must work hard on the issue, because although Bentley Map supports topologies, this is rather crazy (*). Additionally it not easily supports complex geometries, that perhaps are not given much in the cadastre but indeed in other layers as ground cover or risk areas, to put a couple of examples. With Geographics they were converted in cells or complex shapes, with which could not be done topological analysis. It should simplify the process; because most programs have come a long way in this, for example, using the fucking Manifold GIS does an outstanding job without much complicated job. This works with tools / topology factory, you just have to select the objects and it lifts a panel that includes an immediate analysis in accordance with the details of the layer:

  • Proximity (near)
  • overlapping
  • overshooting
  • contiguous branches
  • redundant metrics

Separately if we select them, they are shown in different colors and there is the option of individual or mass self-healing. Make change of tolerance, this is also within a view with scroll options; go to the next, take action and approach.

Finally, the user adapts to suffer or mix tools, but it should not be the accepted practice for a service we pay and we hope it improve over time.


(*) traido de los cabellos: This popular phrase is used when a sitution is rather crazy and strange.

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