Issue with GWR

Question

Hello Community!

I'm currently trying to work with some regression analysis with census data.  I run the OLS analysis for my dependent variable using 5 explanatory variables.  I then moved on to GWR using the same dependent and explanatory variables.  The problem is that I get an error continuously when trying to perform the GWR analysis.  It appears that GWR does not like one of my explanatory variables (Edad - age in Spanish).  I checked the VIF values after running the OLS and all value are way below 7.5.  I created thematic maps of all the explanatory variables.  Perhaps age and distance to coast show some degree of multicollinearity, however, this collinearity does not continue throughout the entire study area.  I am attaching a document with all the images and the error.

Any help regarding this issue will be greatly appreciated.  Thank you so much for your time and feedback.

Leandro

GWR_ISSUE.doc

popupexample.jpg

BrettStokes_8-1631753728971.png

RoshanBhandari · Answer

Dear @LaurenScott ,  your idea of subtracting mean from data was extremely helpful. Thanks a lot. Btw, can I refer this idea from the literature to cite them in my methods?

RoshanBhandari · Answer

Dear @LeandroGonzalez  your idea of subtracting mean from data was extremely helpful. Thanks a lot. Btw, can I refer this idea from the literature to cite them in my methods?

AndrewTimleck · Answer

I looked at log transformations on the geostatistical analysis extension.  I can see those transformations happenning but I do not know how exactly apply that conversion to the data (i.e. create a new field with the log transformation values so I can use them and reduce bias).

may be the blind leading the blind .... but I'll give it a shot:

1) Add a new field, call it something like log_var1
2) I used Field Type DOUBLE, Precision: 18, Scale : 9
3) Right click on the header of the column, select field calculator
4) from the "Functions" menu on right of box click "Log ()"... and it's added to the "log_var1 = " box
5) From the Fields list, above, find the variable you want to transform and double click it to add it.
6) Click on 'OK' to compute the field.

You can then right click on the header and select "Statistics" and real quick see how the distribution of the variable changes.

Hope that helps.

Andrew