Bastien, your report is very helpful.
I believe I managed to get overlay()'s efficiency back into the over()
methods. Because of the way the code is set up for over(), the
efficiency gain will propagate to all over() methods where the second
argument has attributes. Committed to svn on r-forge; wi
For this example at least you are severely handicapping rgeos as gIntersect
needs to create all new points that result from the intersections which then
need to be translated back to R from the geos representation. If you use
something like the following you should see much better results:
> sy
Thanks to Francis and Edzer for their responses.
I been working on my problem for the last 2 days and I managed to get some very
interesting information. I also prepared a reproducible example so people can
try it.
I've found 3 functions that do the thing I want:
1) %over%
2) overlay() (which
I made the same experience as Francis Markham. I recently used the over
function to check in which polygon from a shapefile a large number of points
fall, and it crashed because of memory requirements. I was running the function
in the cloud with 12GB of RAM...
Here are some details and below i
I've had examples in the past where using %over% from the sp package takes
all available RAM (7GB) and several hours, while ArcGIS takes about 300MB
and 5 minutes, so I would agree that there is plenty of room for
improvement here. I'll try to give a reproducable example in the coming
weeks when I
Dear Bastien,
the %over% method was primary written to work, and it seems that it did.
It is hard to tell why ArcGIS is so much faster without access to its
source code, and your data. Chances are that it uses a spatial index,
and R does not.
Talking about spatial indexes, you might want to try
Dear geo-list,
I'm just starting using R and the rgdal package to manage and create some
shapes and I am hitting some speed issues while using the %over% function. R is
significantly slower than ArcGIS.
Here is what I'm doing (I've shorten the code to make it easier to follow, I
don't expect i
