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st: SPATGSA
From
Ivan Png <[email protected]>
To
[email protected]
Subject
st: SPATGSA
Date
Sun, 31 Oct 2010 11:34:07 +0800
Greetings!
I'm trying to estimate spatial correlation. I gave the following commands:
use moran_working.dta , clear
spatwmat , name(wts) xcoord(longitude) ycoord(latitude) band(0, 1000)
spatgsa rd_int , weights(wts) moran
The result was nothing:
The following matrix has been created:
1. Inverse distance weights matrix wts
Dimension: 511x511
Distance band: 0 < d <= 1000
Friction parameter: 1
Minimum distance: 0.0
1st quartile distance: 0.5
Median distance: 2.8
3rd quartile distance: 5.4
Maximum distance: 10.5
Largest minimum distance: 2.59
Smallest maximum distance: 5.79
. spatgsa rd_int , weights(wts) moran
Measures of global spatial autocorrelation
Weights matrix
--------------------------------------------------------------
Name: wts
Type: Distance-based (inverse distance)
Distance band: 0.0 < d <= 1000.0
Row-standardized: No
--------------------------------------------------------------
Moran's I
--------------------------------------------------------------
Variables | I E(I) sd(I) z p-value*
--------------------+-----------------------------------------
rd_int | . -0.002 0.003 . .
--------------------------------------------------------------
*1-tail test
======================
I also tried
spatwmat , name(wts) xcoord(longitude) ycoord(latitude) band(0, 1000)
spatgsa rd_int , weights(wts) geary
and also got nothing:
The following matrix has been created:
1. Inverse distance weights matrix wts
Dimension: 511x511
Distance band: 0 < d <= 1000
Friction parameter: 1
Minimum distance: 0.0
1st quartile distance: 0.5
Median distance: 2.8
3rd quartile distance: 5.4
Maximum distance: 10.5
Largest minimum distance: 2.59
Smallest maximum distance: 5.79
. spatgsa rd_int , weights(wts) geary
Measures of global spatial autocorrelation
Weights matrix
--------------------------------------------------------------
Name: wts
Type: Distance-based (inverse distance)
Distance band: 0.0 < d <= 1000.0
Row-standardized: No
--------------------------------------------------------------
Geary's c
--------------------------------------------------------------
Variables | c E(c) sd(c) z p-value*
--------------------+-----------------------------------------
rd_int | . 1.000 0.187 . .
--------------------------------------------------------------
*1-tail test
=====================
I've had the same problem with hundreds of similar data-sets.
Grateful for your help. In case it would help in debugging, I've
uploaded a sample data-set here:
http://www.comp.nus.edu.sg/~ipng/research/moran_working.dta
Many thanks
Ivan Png
--
Skype: ipng00
T: +65 6516 6807
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