[postgis-devel] Distance operator in presence of M

[Havard Tveite]

I guess scaling is sufficient for most cases.
Does ST_Scale work for M (the documentation talks about
XFactor, YFactor and ZFactor)?

Håvard

On 8/6/2015 13:39:PM, Sandro Santilli wrote:
> On Sat, Jun 06, 2015 at 02:32:22AM +0200, Håvard Tveite wrote:
>
>> To be able to do distance calculations on data with M
>> values, we need to be able to transform the M value into
>> a "compatible" dimension (resulting in a Euclidean space).
>> When M is time, this transform could be based on a
>> user-specified velocity (d=v*t).  In general, a
>> user-specified function (as suggested by Greg) that does
>> this transformation would be useful.  Or perhaps some
>> pre-defined functions with user-specified parameters
>> could work (d=a*M).
>
> I was thinking we should just allow scaling M with the
> existing ST_Scale function. That should do, right ?
>
> See https://trac.osgeo.org/postgis/ticket/3062
>
> --strk;
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