Changes between Initial Version and Version 1 of Ticket #3719, comment 13


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Timestamp:
Mar 15, 2018, 6:36:53 AM (6 years ago)
Author:
tiiipponen

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  • Ticket #3719, comment 13

    initial v1  
    11Sorry for unclear question. I know the default tolerance is 32 segments per quadrant, which is too parse and which is the reason for all problems in this ticket.
     2
    23The real question is: if we use this tolerance-parameter you propose inside PostGIS with some default tolerance value, then what would be good value?
    34And because different users want to use different tolerance, how can we make it possible for them to set that parameter in table-level?
    45
    5 Some example calculation about values:
    6 
     6{{{
    77From equation:
    88cos(angle_sector / 2) = (radius - tolerance) / radius
    … …  
    2323=>
    2424tolerance = 0.000003m which is quite enough for practical use I think.
     25}}}
    2526
    2627Because arc is just mathematical entity to express line and necessarily not any real structure, people can have arcs with radius for example from 1mm to 100km.