Repair Topology

[kz9283]

Hi,

I am trying to calculate the topology parameters for a digitised fracture network.

However the nodes and branches are not being recognized. I believe there is an issue with the topology. When I try to run the repair network tool or snap nodes the issue does not resolve.

I have ensured the data is in a projected coordinate system (EPSG 28356) How can I fix this?

Thank you!

[BjornNyberg]

Hi @kz9283

This is unfortunately a difficult issue to diagnose without an error message. Can you perhaps share an example area to reproduce the error?

[kz9283]

Hi @BjornNyberg ,

I have digitized the fractures in QGIS using the GeoTrace2 plugin (https://plugins.qgis.org/plugins/geo_trace/). The input layer is a Multi linestring in the same projected coordinate as the project.

This is the error message I receive. I believe it has something to do with the topological preprocessing. Is there an order to which the tools (repair topology, connect nodes etc) should be run?

Thank you for your help.

[BjornNyberg]

@kz9283

I have not personally used geo_trace and therefore do not know the exact output types/precision that it provides. Could you perhaps provide an example? You can always share it via dropbox, google drive or something similar.

Cheers, Björn

[kz9283]

Hi Björn,

Thanks for your reply. I've used a manually traced dataset produced in QGIS and changed the fields to be comparable to the Hartland example dataset (e.g. ID, length fields). This seems to have resolved the issue - I'm now able to compute the topology parameters.

Do you have any recommendations for manual digitistion in QGIS - is it best to enable the snapping and/or 'enable topological editing' tool?

Thanks for your help!