MapInfo Pro

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  • 1.  Concave Hull

    Posted 07-25-2024 12:05

    Is there a tool out there to calculate the Concave Hull around a set of points in MapInfo?

    (not Convex)



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    John Ievers
    CDR Group Limited
    Hope Valley, United Kingdom
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  • 2.  RE: Concave Hull

    Posted 07-26-2024 04:10

    I'd be really interested in this too! Keeping my fingers crossed!



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    Gavin Thomas
    Knowledge Community Shared Account
    Burlington MA
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  • 3.  RE: Concave Hull

    Posted 07-26-2024 06:46

    I found an old tool called AlphaShapes by Nyall Dawson in Oz and it's on Github with the mb code too.

    nyalldawson/mi-alphashapes: Alpha shapes for MapInfo (github.com)

    2 functions: Delauney Triangles and the Alpha Shapes (convex hull which can be adjusted via a value which adjusts the result). Quite neat.

    This works fine in MI Pro v15 32-bit but only the Delauney Triangles work in 64-bit MI Pro



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    John Ievers
    CDR Group Limited
    Hope Valley, United Kingdom
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  • 4.  RE: Concave Hull

    Employee
    Posted 07-29-2024 11:59

    Hmm. I tried it in v2023 and got an error creating table.

    But then I ran it on a debug version and it completed:

    So maybe we can figure out how to get it working



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    Bob Fortin
    Software Architect and Distinguished Engineer
    MapInfo Pro Development Team
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  • 5.  RE: Concave Hull

    Posted 09-04-2024 06:49

    Hallo,

    I've not used github before.  Would someone be able to explain which of the many folders / files I need to download to be able to have a go with this tool?

    Thanks,

    Alan.



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    A Oliver
    Geospatial Anayst
    West Midlands Police - Perry Barr Police Station
    BIRMINGHAM
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  • 6.  RE: Concave Hull

    Posted 09-04-2024 16:38

    Hi Alan

    I went for Version 105 and you just need the mbx file - unless you want to adapt the mapbasic code, then there is the mb and mbo and mbp.

    It works in MapInfo v15 >Run MapBasic

    Cheers



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    John Ievers
    CDR Group Limited
    Hope Valley, United Kingdom
    ------------------------------



  • 7.  RE: Concave Hull

    Employee
    Posted 09-05-2024 02:08
      |   view attached

    Hi

    I have attached a version that can run in v2021.1 and newer. The error relates to creating a table without a fully qualified path.

    This version also comes with improved performance in newer versions of MapInfo Pro as it adopts the use of the keywords NoSelect Hide for Select statements.

    It could potentially be improved further as there is still a long list of queries being creating during some of the processing.



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    Peter Horsbøll Møller
    Principal Presales Consultant | Distinguished Engineer
    Precisely | Trust in Data
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    Attachment(s)

    zip
    alpha_shapes x64.zip   7 KB 1 version