[R] Error in qr.solve(crossprod(xsar), t(xsar)) when using SpatialFiltering

Aquarius yiyiwang.ut at gmail.com
Sat Jun 25 03:28:32 CEST 2011


I am using the R function SpatialFiltering to my land value dataset.

I compute a 500 by 500 binary spatial weight matrix (W) based on the x and y
coordinates in my land value dataset. The nearest 6 neighbours were given a
value of 1. By construction Wii=0. So my weight matrix look like
0 ..1 0 0 ... 1 0
0......1.....0...
....0...1......
# of rows= 500. # of columns =500. Row sum =6 (because of nearest
neighbour=6)

Then I fed the data into the SpatialFiltering fxn:
tmp = mat2listw(wt);
results= SpatialFiltering(LandValue ~ 1+AI+Area_SF_08+Dist2CBD05, data=lu2,
nb=tmp$neighbours, style="W", ExactEV=TRUE, zero.policy=TRUE)

%%%%%%%%%%%%%%%%%%%
Then an error message occur:
Error in qr.solve(crossprod(xsar), t(xsar)) : 
  singular matrix 'a' in solve

Can someone help me out?

Thank you so much in advance!

Yiyi

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