Make positional accuracy tools from 1.8 work in 2.6

[maicke]

hello,

I am a master student at KU Leuven (belgium university) and i am doing my thesis about OSM quality. I wanted to test some of your QGIS processing tools like the buffer method and the hausdorff distance for positional accuracy. But i cant get them working. i have installed OSGeo4W and with that i have installed QGIS 2.6. But the scripts don't work in that version. Is there a way to install an older version of QGIS with OSGeo4W or is there an other way to install QGIS 1.8 so the scripts work?

[anitagraser]

Hi, You can get old versions from http://qgis.org/downloads/ Imho, it would be better to update the scripts to the new version but I won't have time for that in the foreseeable future.

[brylie]

@maicke thanks for your feedback :-) Are you getting a specific message? What are some steps I can take to reproduce this issue?

[maicke]

Hi, Thank you for your answers. Using the older versions gave some conflicts with the new version of numpy. So that was pretty mutch a dead end. So i am now updating the scripts to the new version. I got some of them working like the: find_similar_line_feature.py (which included the hausdorff distance). But how did you do the buffer method that you explained in this article http://anitagraser.com/2013/12/15/osm-quality-assessment-with-qgis-positional-accuracy/ . I saw in your conference presentation that you have some models and scripts for them (https://www.youtube.com/watch?v=RXr4s9MILOw#t=230). But i can't seem to find them.

[anitagraser]

I assume you mean this model: Screenshot: https://github.com/anitagraser/QGIS-Processing-tools/blob/master/1.1/models/graph_covered_by_buffered_reference_graph.png Source: https://github.com/anitagraser/QGIS-Processing-tools/blob/master/1.1/models/graph_covered_by_buffered_reference_graph.model

[Revo86]

@maicke i would love to read your thesis and try out your models in a dataset, which i have to assess in my thesis! :)

[ktjaco]

@anitagraser Does the graph vs. reference graph model (https://github.com/anitagraser/QGIS-Processing-tools/blob/master/1.1/models/graph_covered_by_buffered_reference_graph.model) work in QGIS 2.18.2? I've had some trouble opening it in QGIS 2.18.2.

[anitagraser]

@ktjaco Unfortunately, the models are not compatible between Processing 1.1 and current Processing versions. They would have to be recreated based on the screenshots in my paper.

[ktjaco]

@anitagraser Thank you! I'll give it a try. A portion of my thesis is very similar to this except I am analyzing Ottawa, Ontario, Canada.

[ktjaco]

@anitagraser I was successful implementing the street network positional accuracy model for a small region but when I try it with a much larger area of interest in Ottawa I find that it is taking a very long time. It hasn't completed and it has been running for approximately 12 hours. I've been tracking the performance and I am getting around 30-40% CPU performance. Is this issue a matter of the processing power of my machine?

[anitagraser]

@ktjaco one issue with computationally expensive operations is that Processing does not support multi-threading. You could try to implement a multi-threading approach yourself, help the Processing developers to add multi-threading, or try a divide&conquer approach which subdivides your area of interest into smaller bites.

[ktjaco]

@anitagraser I've created a successful model using the OS Grid Squares plug-in to split my area of interest in smaller regions. I've uploaded some of my models on GitHub.

https://github.com/ktjaco/QGIS-Processing

Feel free to try it out or comment on them!