On Thu, Jan 16, 2014 at 1:09 PM, Barry Rowlingson <
b.rowlingson@lancaster.ac.uk> wrote:

> Well, back when I wrote 'rmap' I abstracted out the storage of the
> data from the data object... So your object in R could represent a
> subset of a shapefile, and the code only grabbed that chunk of the
> shapefile when it was needed, for example to plot (the R object was
> basically the name of the shapefile plus a selection vector).
>
> Then we threw that code out and sp classes were born!
>
>  I've often thought about restoring some of this kind of
> functionality, but R's object-oriented classes just frustrate me. Its
> not so simple to build a superclass of sp class objects. Or maybe it
> is now? For some value of 'simple'...
>
>  Suppose you had a gigantic spatialite db - if you want to work with
> it spatially (mapping, rgeos) you are going to have to get the bits
> you need into main memory, so the simplest is just to load selections
> into sp-class objects. Is that already possible with the OGR
> spatialite driver? Can you also load subsets of shapefiles using some
> SQL passed to the OGR shapefile driver?
>
>  What would you want to do on whole-dataset objects of this class?
> Would you want to do the processing on the database if possible (if
> its PostGIS or Spatialite)? Or have an automatic chunking procedure
> for operations that don't need the whole database at once, such as
> finding centroids of polygons?
>
> Hmmm thoughts thoughts thoughts and no action :( Sorry!
>

Barry,

I'll have more to say on this in a couple of weeks.

THK


>
> Barry
>
>
>
> On Thu, Jan 16, 2014 at 6:52 PM, Jonathan Greenberg <jgrn@illinois.edu>
> wrote:
> > r-sig-geo'ers:
> >
> > As vector datasets are getting a lot larger, there is a limitation
> > with the Spatial* formats in that they must be loaded into main
> > memory.  I was curious what folks who have been dealing with massive
> > vector files have come up with working within the R environment?  Has
> > anyone played around with file geodatabases or spatialite formats (for
> > instance)?  How are you creating/querying the data?
> >
> > Thanks!
> >
> > --j
> >
> > --
> > Jonathan A. Greenberg, PhD
> > Assistant Professor
> > Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
> > Department of Geography and Geographic Information Science
> > University of Illinois at Urbana-Champaign
> > 259 Computing Applications Building, MC-150
> > 605 East Springfield Avenue
> > Champaign, IL  61820-6371
> > Phone: 217-300-1924
> > http://www.geog.illinois.edu/~jgrn/
> > AIM: jgrn307, MSN: jgrn307@hotmail.com, Gchat: jgrn307, Skype: jgrn3007
> >
> > _______________________________________________
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>
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