I always use lat/long, i dont convert. You must know, not all functions in
MySQL have been implemented. For distance we implemented out own SQL
statement.
SELECT id, ( 6371 * acos( cos( radians(".$fLat.") ) * cos( radians(
X(geo) ) ) * cos( radians( Y(geo) ) - radians(".$fLng.") ) + sin(
radians(".$fLat.") ) * sin( radians( X(geo) ) ) ) ) AS distance
FROM verkooppunt
In this query, geo is a binary geometry field. $fLat and $fLng are the lat
and long of the point we want to compare to. Perhaps this helps.
2009/4/10 px <[email protected]>
>
> ur info on geom datatypes is helpful.
>
> specific to thepart "how do we store the lat/lng decimals (google
> map api) to ... "
>
> i will state is more clearly cause i am grappling with this for the
> last few days
>
> i click on Innsbruck - the latlng returned by google map api is
> lat: 47.2626455432058
> lng: 11.394656195068347
>
> For Munchen its
> lat: 48.138900363549034
> lng: 11.577990545654284
>
> i preserve all the decimal and query the length from Innsbruck to
> Munchen
>
> SELECT GLENGTH(GEOMFROMTEXT('LINESTRING(47.2626455432058
> 11.394656195068347, 48.138900363549034 11.577990545654284)'))
>
> results in - 0.89522845926586
>
> is it as simple as this?
>
> just read this point "Well-Known Text is a format for the textual
> representation of geometric objects. The UTM coordinates
> of "Innsbruck" in WKT format look like this: POINT(681547.32
> 5237595.88)"
>
> should i be translating the lat lng to UTM coordinates?
> thus saving Innsbruck to a point datatype as POINT(681547.32
> 5237595.88) rather than POINT(47.2626455432058 11.394656195068347)
> and then apply the geom function on the data.
>
> i am bordering on desperation now. thanks for ur time anyway.
>
> cheers,
> px
>
>
>
> On Apr 10, 12:22 pm, Björn Brala <[email protected]> wrote:
> > If you want to implement the functions from MySQL you need to store them
> in
> > a geometry column. To make sure its fast create an index on that column;
> >
> > ALTER TABLE markers ADD SPATIAL INDEX(geo_field);
> >
> > This will make it a lot faster.
> >
> > When cerating Polygons or lines, be sure the decimal character is a
> point. I
> > use for polyline;
> >
> > LINESTRING(52.4 4.6, 53.3 4.5) etc.
> >
> > And polygon;
> >
> > POLYGON((52.6 4.7, 43.3 4.6, 50.7 4.8))
> >
> > Double the (()) because polygon can consist of inner and outer.
> >
> > Hopefully this helps.
> >
> > 2009/4/10 px <[email protected]>
> >
> >
> >
> >
> >
> > > hi,
> >
> > > i am working on a loc based concept. stuck on a few issues.
> >
> > > how do we store the lat/lng decimals (google map api) to a "point"
> > > datatype in mysql.
> >
> > > example for paris
> > > lat - 48.8372
> > > lng - 2.33
> >
> > > do we store it as GEOMFROMTEXT('POINT(48.8372 2.33234)') or do
> > > i need to convert to any specific format.
> >
> > > storing it as float column will not suffice as all the spatial quering
> > > fu
> >
> > > dont i do need to store them as point/linestring/polygon to use data
> > > query functions like glenght/exteriorring ?
> >
> > > eg given "n" mile radius from a base point finding matching locations
> >
> > > thanks,
> > > px
> >
> > --
> > Bjorn Brala
> > ----------------
> > GeoStart.nl- Google maps - Swis Webdesign
>
> >
>
--
Bjorn Brala
----------------
GeoStart.nl- Google maps - Swis Webdesign
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