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root676 / QNEAT3

QNEAT3 - Qgis Network Analysis Toolbox 3
GNU General Public License v3.0
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Iso-Area Polygon tool results are 10 times bigger #47

Closed guneshland closed 1 year ago

guneshland commented 3 years ago

Version 1.0.4

I tested this tool (Iso-Area Polygon tool (from Point)) to calculate isochrones based on moving speed of the roads. The result surprised me: moving on streets with 60 km/h assigned speed takes as much time as walking on foot. I tried to run Iso-Area as contours with exactly same parameters, then I saw adequate results. I noticed that previous results showed 10 times bigger time than on the second try when isolines were same, but 10 times sparser. I can evade this issue by dividing the result by 10 or multiplying the speed by 10, but this can confuse someone. I haven't tried yet other tools. I hope you will fix that issue. Pictures illustrate the mistake: red lines indicate Polygon tool, black lines indicate contours tool Screenshot 2021-04-23 232113

root676 commented 3 years ago

Thank you for reporting this. Unfortunately I am not able to reproduce this error. I would advise you to check your data and parameters again. The reason why this has to be a problem on the data/parameter side is, that both, Contours as well as Isochrones rely the same method in the background.