[GWR] Missing predictions when number of neighbours is given

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09-08-2011 08:16 AM
MichalCudzilo
New Contributor
Hi everyone,

I have a set of 500 observation, dispearsed in the space, which distribution varies in space (mainly concentrated in the center). I used adaptive kernel to make a model. When AIC or CV criterion is set, everything is ok (besides hetereskedastity of residuals). I tried to define number of neighbours, when gwr is calculating and... yes, there is some strange results. Operation is successful, but I don't know why, some observation are missed (about 1/3 - those, which were on the outskirts, not in the centre). They are in attribute table, but all fields connected with estimation are fulfilled with <<Null>> value.

Any ideas why it happened? As far as I read GWR theory, all observation should be estimated in this case. Only phisically radius should increase, 'cos we take into consideration constant number of neighbours (not distance). So..?

Thx in advance and have a nice evening,
Michal
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LaurenRosenshein
New Contributor III
Hi Michal,

I'm really sorry that you're having trouble with GWR! In order to try to figure out what's going on, if you can provide the following information we can try to reproduce your problem and hopefully fix it!

-What version of ArcGIS are you using?
-What operating system are you using?
-What kind of data are you using? Polygons, points, lines? How many features are there? Are they are in a personal geodatabase, a file geodatabase, shapefiles, or other?

If possible, if you could provide the dataset that was giving you trouble that would be very helpful in trying to reproduce. If this is possible, it will also be helpful to get screenshots of the tool dialogs before you run them, so that we know exactly the parameter choices you're making. If not, the above information should at least get us on the right track.

Again, I'm very sorry that you're having trouble, and we'll do our best to figure it out!

Lauren Rosenshein
Geoprocessing Product Engineer
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