[Mobilitydb-dev] FW: [geos-devel] Problem with ST_FrechetDistance in PostGIS/GEOS

[Regina Obe]

FYI  - Martin updated GEOS to fix what you described

 

https://trac.osgeo.org/postgis/ticket/4992

 

 

 

From: Esteban Zimanyi [mailto:esteban.zimanyi at ulb.be] 
Sent: Sunday, September 19, 2021 6:42 AM
To: Regina Obe <lr at pcorp.us>
Cc: mobilitydb-dev at lists.osgeo.org
Subject: Re: [Mobilitydb-dev] FW: [geos-devel] Problem with ST_FrechetDistance in PostGIS/GEOS

 

We are currently testing several implementations of the Frechet distance based on 

https://towardsdatascience.com/fast-discrete-fr%C3%A9chet-distance-d6b422a8fb77

which itself is based on

https://dl.acm.org/doi/10.1145/3150919.3150924

Indeed, a typical "trip" of a ship, e.g., from the available of the Danish Maritime Authority

https://www.dma.dk/SikkerhedTilSoes/Sejladsinformation/AIS/Sider/default.aspx

contains 10K-30K timestamped points and thus we need an extremely efficient implementation.

 

The current experiments are being developed here

https://github.com/estebanzimanyi/MobilityDB/blob/frechet/src/point/tpoint_discfrechet.c

but this is still far from complete. We will benchmark the various alternatives and choose the right one(s) to make available in MobilityDB.

 

After that we will make the results available in the MobilityDB wiki.

 

 

 

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