[OSM-dev] Grid lines

Jan-Benedict Glaw jbglaw at lug-owl.de
Mon Jan 17 15:45:17 GMT 2011


On Mon, 2011-01-17 15:31:43 +0000, Steve Hill <steve at nexusuk.org> wrote:
> On Mon, 17 Jan 2011, Andy Allan wrote:
> > My approach would be to generate a table with the gridlines in it, but
> > I haven't tried.
>
> I was starting to think that might be the way, but was just curious if  
> anyone had come up with a better programmatic method (e.g. a fancy select 
> sql statement that generates the appropriate geometries on-the-fly or  
> similar, since they are regular repeating geometries - this should be  
> reasonably easy for lat/lon grids but the other types aren't quite as  
> regular so would require some thought)

It's probably not that hard to use PostgreSQL's generate_series() to
build the grid lines. But OTOH, I'd somehow expect the map drawing
application (or library) to generate them. There, you'd probably
better decide what kind of grid to use (eg. lon/lat, which
granularity, or the A/B/C/D  1/2/3/4 grid you often find on printed
city maps).

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw at lug-owl.de              +49-172-7608481
Signature of: They that give up essential liberty to obtain temporary safety,
the second  : deserve neither liberty nor safety.  (Ben Franklin)
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