Visualising the output

[rhiaro]

We need to visualise the output data in a way that clearly shows the consolidation has been useful. Eg...

• counts of nodes/spans that were previously double counted
• visualising how 3 operators (networkProviders) are on a single cable
• ...

[odscjen]

re a count, I'm not sure what the calculation exactly would be but I suspect this can just be added as a new column in the attribute table of the output dataset. That count attribute can then be used as the main visualisation property, e.g. a different colour depending on how many counts the span/node represents.

re. visualising multiple operators on a single cable. Doing this to look like e.g. a bus network map, where each operator is shown as a parallel line, is really tricky and not particularly automate-able unfortunately. However I think that by using the labelling expression builder it should be possible to show labels that show the names of all the operators. If this was combined with the suggestion above it would be a fairly clear indication of where there are multiple operators on the same cable and who they are.

Some potentially useful SE posts to checkout

• https://gis.stackexchange.com/questions/333819/display-lines-which-share-segments-by-offsetting-them-only-where-they-overlap?noredirect=1&lq=1
• https://gis.stackexchange.com/questions/417084/label-containing-multiple-fields

[stevesong]

I feel like there must be a tool for this as I have seen it on various maps such as this one
from AfricaBandwidthMaps If we are stuck, I can write to the author and ask him.

[rhiaro]

Related: #23

[odscjen]

create new column in attribute table with count of networkProviders using field calculator
array_length(networkProviders)

[duncandewhurst]

I feel like there must be a tool for this as I have seen it on various maps such as this one

This might be relevant https://gis.stackexchange.com/questions/239129/shifting-display-of-overlapping-lines-in-qgis/268556#268556

[stevesong]

I wonder if that stackexchange answer is more complex than it needs to be? A polyline is a set of vertices. If the first and last elements of the set are kept the same i.e. at the node points, then is it not a simple transform on the other vertices based on a chosen angle/direction and magnitude? Perhaps the calculation of the angle is tricky but I kind of assumed it would be perpendicular to a straight line drawn between the start and end point of the polyline. Maybe that is what the function is doing and I haven't fully got my head into it yet.

[duncandewhurst]

I haven't reviewed the function in detail, but your suggestion is how I would approach it. Interesting to note the comment from the person that asked the question (who works in telecoms):

That being said, and even if I think this is a feature that should exists in QGIS, the client said that finally it is better to actually draw the polylines separately since their GIS do not handle the situation the same way I thought to do (which was the spatially right way to do)

That aligns with what we saw in the data from Brazil where the parallel lines were encoded in the data, rather than in the presentation.