local R2

Hello,

Thank you very much Roger for your helpful answer. It worked pretty well.

When I run gwr with polygon data I get:

"Warning message:
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
?sum.w
?Min. ? :33.40
?1st Qu.:56.47
?Median :62.22
?Mean ? :62.32
?Max. ? :91.10

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

? ? ? ? ?sum.w
?Min. ? : 36.83
?1st Qu.: 50.90
?Median : 56.49
?Mean ? : 57.56
?3rd Qu.: 62.76
?Max. ? :120.35

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, 27 Nov 2009, Eda Laze wrote:

Hello,

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
sessionInfo().

Hope this helps,

Roger

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.

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--
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