[R-sig-Geo] PostGIS and sp integration
dylan.beaudette at gmail.com
Thu Oct 9 17:44:37 CEST 2008
On Thursday 09 October 2008, Edzer Pebesma wrote:
> Barry Rowlingson wrote:
> > 2008/10/9 Edzer Pebesma <edzer.pebesma at uni-muenster.de>:
> >> Why is this better practice than having a single 100x61 table with
> >> monthly rainfall in the usual columns and a geometry column?
> > Because when I get another year's data, I have to change the table
> > definition. SQL doesn't like that. Keep your original data
> > normalised, that's the idea. Of course you can denormalise for a
> > specific purpose, such as....
> Right, I forgot, SQL doesn't have the $<-
> >> Sounds as if you've not seen the spplot light. If you had a single table
> >> with 60 columns and 100 rows, all that's needed would be
> >> rain = readOGR("bla")
> >> spplot(rain)
> >> given that the rain columns would be useful and fit in the conditioning
> >> plot text boxes (so-called "strips")
> > I'll give that a go. However, I need to get my 60 plots into 60 png
> > files for animation purposes. Can spplot do that? I was just going to
> > draw them into png() devices.
> Yes, but you need to fix the scale bar range ahead of time. spplot is
> just a wrapper around levelplot, so remember to put a print(spplot(...))
> inside loops.
> > Originally I had weekly data...
> Well, yes, in that case animation becomes compelling. Aren't there any
> GIS clients that can do animation with time series of vector maps? I
> only know one for gridded data.
If you are just making maps, and lots of them GRASS might be useful for
automating the process. Here is one such example, with solar radiation data
over the coarse of a normal year:
Soil Resource Laboratory
University of California at Davis
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