albertferras
Seems working normally but no simplification in the result
Tried with different layers and different parameters on QGIS, simplipy seems to do the job but I end up with the same layer as entry.
can you provide more information? What parameters are you using? Can you upload here or send me by email the geometries you're trying to simplify?
Thanks for this answer!! I tried on this shapefile (I only could sent a part of it because of the size and I could not find your email adress), it comes from a raster map transformed into a polygon file, with these parameters : Algorithm Douglas-Peucker Tolerance 0.20 (just to be sure I tested with other numbers 1, 10, 0.001 but nothing changed) Constraints : Prevent shape removal (with 3 minimum points for polygons), Use topology (as I am working on a map), snap precision 0.1 with Simplify shared edges and non-shared edges.
I obtained a layer called SimpliPy 0, 1 or 2 depending on the number of tests I ran. But it is exactly the same as the original one. I am sure I am doing something wrong but I could not find what: the installation seemed successful and I have a result so I guess I am using wrong parameters.
Thank you for you're help.
Have a nice day
Thanks for the additional info! I'm not at home nor with laptop so I'm not able to analyze it properly until saturday.
With a quick test simplifying the geometries you provided in QGIS, I think that the issue is related to an issue in which projections with unit sizes > 100 makes the 'use topology' not work properly. I've already fixed this issue in the upcoming simplipy 0.6 + I will also probably remove the 'snap precision' field in the plugin and make it automatically computed.
There's also a bug in the latest version of simplipy in which 'prevent shape removal' fails (fixed in 0.6).
Anyway, this is just a guess. I will verify it as soon as I can and get back to you.
By the way, which version of simplipy are you using? Do you see any error message in the simplipy log?
Thank you for reporting this!
Thanks for this quick answer! I use the version 0.52 of simplipy and when I run it, an error message appears related to the projection. I suppose that it makes sense with what you said in your last message. We'll see. If it is fixed in 0.6, I will wait for the new version. Thanks again.
Hi again.
The reason why you were not getting any simplification is because the tolerance you were using (1, 10 or 0.001) is too small. Since the minimum segment size in the dataset is ~50 units, you should be using tolerance higher than that.
However: If you try with, let's say, tolerance=100, your qgis will most likely crash or raise an error. I've also tried to simplify your dataset in the upcoming simplipy v0.60 and I could get it to simplify successfuly. Unfortunately I had to disable prevent shape remove due to some remaining bugs.
Before releasing 0.60 I have to fix this bug and some others, too.
In addition to this, I will add some help messages after simplification to help users configure tolerance properly. Example: 'Try using tolerance > X for higher simplification)'
I will keep this ticket open until 0.60 is released. You should get a notification/email when this happens.
Thanks!
Hi,
thank you so much for these explanations. Even with the risk that my QGIS crash, I will try simplification with a proper tolerance just to see the result and I will wait until the release of 0.60.
Thanks again for your help and time.