[R-sig-Geo] local R2
edalaze at gmail.com
Mon Dec 7 13:07:46 CET 2009
Thank you very much Roger for your helpful answer. It worked pretty well.
When I run gwr with polygon data I get:
In gwr(formula = AFCCH07HA ~ ALDRO12MEA + ALDRO1MEAN + ALHSETTMEA + :
data is Spatial* object, ignoring coords argument"
However, I may provide now two results in one of combinations of variables I
use. I use the same number of neighbors and variables in both cases,
the only change is as follows:
In case one I use longlat =TRUE and in case two I do not write longlat=TRUE.
case one (longlat=TRUE): local R2 values vary from 0.1651 to 0.5328
gwr.e pred localR2
Min. :-465.4243 Min. :-142.267 Min. :0.1651
1st Qu.: -17.4693 1st Qu.: 5.429 1st Qu.:0.2461
Median : -3.2120 Median : 16.735 Median :0.2788
Mean : 0.3215 Mean : 17.798 Mean :0.2835
3rd Qu.: 16.0616 3rd Qu.: 29.726 3rd Qu.:0.3181
Max. : 321.4507 Max. : 162.569 Max. :0.5328
case two (without longlat=TRUE): local R2 values vary from 0.06066 to 0.70522
gwr.e pred localR2
Min. :-323.5487 Min. :-244.457 Min. :0.06066
1st Qu.: -13.4717 1st Qu.: -1.223 1st Qu.:0.32168
Median : -1.2330 Median : 14.144 Median :0.38511
Mean : 0.9375 Mean : 17.181 Mean :0.40192
3rd Qu.: 9.5695 3rd Qu.: 38.060 3rd Qu.:0.47538
Max. : 320.2477 Max. : 176.522 Max. :0.70522
Min. : 36.83
1st Qu.: 50.90
Median : 56.49
Mean : 57.56
3rd Qu.: 62.76
I thought that adapt=0.01 (number of neighbors) could decide on
weights. Visualisation of map differs, map two is rather a "surface".
Does it mean that weights differ from case one to two due to
the fact that "longlat = TRUE uses distances on the ellipse with WGS84
parameters" as described in the spgwr manual updated in June 2009.
The polygon data are projected in:
Projected Coordinate System: WGS_1984_UTM_Zone_34N.
I would welcome very much an accurate response, despite my efforts to
get the answer these days by myself.
Thank you in advance
On Fri, Nov 27, 2009 at 1:12 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
> On Fri, 27 Nov 2009, Eda Laze wrote:
>> I am currectly using gwr in R to get local R2. I have a shape file -
>> polygon data.
>> When I write codes as below: case 1 and 2, I get two different Local
>> R2 values and maps:
>> case1.adpt<-gwr(FCHA~PAC1+PAC2+PAC6, data=filename,
>> coords=cbind(filename$X, filename$Y), adapt= 0.01, longlat=TRUE).
>> case2.adpt<-gwr(FCHA~PAC1+PAC2+PAC6, data=filename,
>> coords=cbind(filename$X, filename$Y), adapt= 0.01, hatmatrix = TRUE,
>> se.fit=TRUE). Local R2 have different values from case 1 and map is
>> different as well.
> In the second case, you are not using longlat=TRUE, which will give rather
> different weights. Please only give examples with available data sets, and
> include say the first 5 local R2 values, so that helpers know that they are
> looking at the same thing as you are. Always state the output of
> Hope this helps,
>> Furthermore, when I visualize case 1: i.e., local R2 on map, each
>> polygon has a certain value and responding color while in case 2: map
>> shows clustering of Local R2 (values) similar to Georgia case study.
>> However, I wonder why this happen and which is the right way to get
>> local R2.
>> I read spgwr manual and update. Though an accurate answer is very welcome.
>> Thank you.
>> R-sig-Geo mailing list
>> R-sig-Geo at stat.math.ethz.ch
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand at nhh.no
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