An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20120723/3db436ec/attachment.pl>
unable to run spatial lag and error models on large data
2 messages · shish matt, Roger Bivand
1 day later
shish matt <shishm <at> yahoo.com> writes:
Hi: First my apologies for cross-posting. A few days back I posted my queries ar
R-sig-geo but did not get any
response. Hence this post.
Since your message never reached that list - did you check? - that isn't very surprising. Try again properly on R-sig-geo.
I am working on two parcel-level housing dataset to estimate the impact of
various variables on home sale
prices. I created the spatial weight metrics in ArcGIS 10 using sale year of four nearest houses to assign weights. ?
Create them in R, much less error prone. knn2nb(knearneigh()). A lot of problems arise from badly imported weights, but yours below seem OK.
Next, I ran LM tests and then ran the spatial lag and error models using spdep package. I run into five issues. Issue 1: When I weight the 10,000-observation first dataset, I get the
following message: Non-symmetric
neighbors list. ? Is this going to pose problems while running the regression models? If yes,
what can I do? What do you think? If you are using nearest neighbours, only a very unusual set of points would give symmetric neighbours, and that would likely also have subgraph problems.
Issue 2: The spatial lag and error models do not run. I get the following message (the models runs on half the data, approx. 5,000 ?observations. ?However, I will like to use the entire sample). ?
Read the help pages, method= argument. For larger data sets, use "LU" or perhaps "MC" when the weights are not symmetric.
Error: cannot allocate vector of size 880.0 Mb
.solve=1.0e-20)
When I am able to read the data file using filehash package. ?However, I still get the following error message when I run the models: Error in matrix(0, nrow = n, ncol = n) : too many elements specified
No idea, almost certainly caused by not reading the documentation. Try on the original list.
[[alternative HTML version deleted]]
DO follow the rule of not posting HTML!