1. Exquisite Tweets from @underdarkGIS, @hruske, @bitnerd

    billdollinsCollected by billdollins

    underdarkGIS

    Anita Graser

  2. This is doable by using daterange or tstzrange types for temporal and postgis for spatial aspects. postgresql.org/docs/current/s…

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    hruske

    Zejn

  3. Do you know any examples where this is used to model moving objects e.g. cars or animals? #gistribe

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    underdarkGIS

    Anita Graser

  4. No, not really. I can come up with an example, if it helps.

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    hruske

    Zejn

  5. If it's not too much trouble, that would be great! Essentially, I envision a moving point (trajectory) datatype

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    underdarkGIS

    Anita Graser

  6. Missing tweet: 761381714174226432

  7. e.g. which truck passed checkpoint A during a given hour, should interpolate positions between observations

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    underdarkGIS

    Anita Graser

    or when and where were truck A and B at the same location

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    underdarkGIS

    Anita Graser

  8. Missing tweet: 761538236367765504

  9. between the temporal and linear referencing in postgis, all the functionality is there

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    bitnerd

    David Bitner

  10. .@bitnerd @pwramsey @hruske lot of queries working already, thanks to your recommendations. Any tips for computing speeds along LinestringM?

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    underdarkGIS

    Anita Graser

  11. You could do a sum(ST_Length(geom, true)) / (upper(timeslice) - lower(timeslice)) calc to get avg. speed @bitnerd @pwramsey

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    hruske

    Zejn

  12. thank you! Was thinking of speed between consecutive points rather than just average over whole trajectory

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    underdarkGIS

    Anita Graser

  13. Yeah, you don't need to sum it, you can do this per row, at least as per my example, and get segment speed. @bitnerd @pwramsey

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    hruske

    Zejn

  14. underdarkGIS

    Anita Graser

    any recomm. to get location along LinestringM trajectories at a certain time each day, e.g. any day at midnight?

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    underdarkGIS

    Anita Graser

  15. Missing tweet: 833718437528510465

  16. I can query one certain day at midnight but not all possible midnights that way, as far as I can tell ...

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    underdarkGIS

    Anita Graser

  17. ooooh, totally doable. My kind of puzzle, will play tmrw when at computer

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    bitnerd

    David Bitner

  18. great, thank you! I'll also give this puzzle a go some more

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    underdarkGIS

    Anita Graser

    your optimism was a great motivation, here's my first take, if trajectories don't cross day borders

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    underdarkGIS

    Anita Graser

    Nice work! Here's the solution to the speed along trajectory question btw anitagraser.com/2016/10/09/mov…

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    underdarkGIS

    Anita Graser