[Qgis-user] [QGIS-Developer] Geodesic Line Simplification

[C Hamilton]

Nyall,

I have this partially implemented and will get back with you in a few days.

On Wed, Oct 2, 2019 at 7:51 PM Nyall Dawson <nyall.dawson at gmail.com> wrote:

> On Wed, 2 Oct 2019 at 01:30, C Hamilton <adenaculture at gmail.com> wrote:
> >
> > I am guessing this is working on Cartesian coordinates and not geodesic
> which is fine if you have a local projection. I think I will go ahead and
> implement some similar geodesic algorithms. Thank you for the GRASS link.
> It will help.
>
> Hi Calvin,
>
> I think there's a strong use case for adding this to the c++ API.
> Would you be willing to put together a proof of concept in Python code
> and I'll port it to c++ for you?
>
> Nyall
>
>
> >
> > Thanks,
> >
> > Calvin
> >
> > On Tue, Oct 1, 2019 at 7:45 AM Áron Gergely <aron.gergely at rasterra.nl>
> wrote:
> >>
> >> Hi Calvin and list,
> >>
> >> Have you looked at the GRASS GIS v.generalize tool?
> https://grass.osgeo.org/grass64/manuals/v.generalize.html
> >>
> >> The Douglas-Peucker algorithm is implemented there and I have used that
> with (topologic)success recently on many touching polygons. Should work for
> polylines too!
> >>
> >> Best regards,
> >> Aron
> >>
> >> On 01/10/2019 08:19, Tim Sutton wrote:
> >>
> >> Hi
> >>
> >> On 26 Sep 2019, at 17:13, C Hamilton <adenaculture at gmail.com> wrote:
> >>
> >> Are there any geodesic QGIS algorithms that simplify lines? "Simplify"
> just uses the projection units of measure. If there isn't I thought I would
> add this to the Shape Tools plugin. I could easily implement the
> Douglas-Peucker algorithm using geodesic math.
> >>
> >> For GPS tracks I also see a need to throw out all points that are less
> than a certain distance or less than a certain time interval. I don't see
> any simplification algorithms that make use of time. Am I just missing them?
> >>
> >>
> >> No I don’t think we have any time based simplifiers - would be a great
> addition!
> >>
> >> Regards
> >>
> >> Tim
> >>
> >>
> >>
> >>
> >> Thanks,
> >>
> >> Calvin
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> >>
> >> —
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Tim Sutton
> >>
> >> Co-founder: Kartoza
> >> Ex Project chair: QGIS.org
> >>
> >> Visit http://kartoza.com to find out about open source:
> >>
> >> Desktop GIS programming services
> >> Geospatial web development
> >> GIS Training
> >> Consulting Services
> >>
> >> Skype: timlinux
> >> IRC: timlinux on #qgis at freenode.net
> >>
> >> I'd love to connect. Here's my calendar link to make finding time easy.
> >>
> >>
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> >
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