[R-sig-Geo] local R2

[Eda Laze]

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, Nov 27, 2009 at 1:12 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
> 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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>> R-sig-Geo at stat.math.ethz.ch
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>
> --
> 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
>
>