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Hi, I am working with GWR and can run it fine, however I am having problems with the results and what exactly to map. First of all just to check, the results titled C1, C2 and so on are the explanatory variable coefficients? Are these coefficients the coefficients of determination for each independent variable or something else? Also, I've been reading around the subject and finding out what is best to actually map to go into my reports, are these the explanatory variable coefficients best to map or I've read about dividing the explanatory variable coefficients by the standard errors to get the t-value to map. Sorry it this is very simple, I am new to ArcGIS and regression! Any advise would greatly be received. Thank you 🙂
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02-29-2012
07:25 AM
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Thanks David. My data is made up of a base map (Amazon Basin) and an excel document joined to it which shows incidence rates per municipality. The base map has a coordinate system and I've tried to project map once the join has happened but I am still ending up with decimal degrees. I've checked the data source to see which coordinate system the base map has and its the GCS_South_American_1969 (please see below). Is there a way around this so I can use Moran's as I would like to be able to back up my choice of distance? Could I just use the data from the 'Calculate Distance Band' tool which gives a maximum distance so every location has one neighbour? Thanks. Geometry Type: Polygon Geographic Coordinate System: GCS_South_American_1969 Datum: D_South_American_1969 Prime Meridian: Greenwich Angular Unit: Degree
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02-23-2012
08:06 AM
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Hi, I am running the hot spot analysis to identify clusters of high and low areas of respiratory diseases. I have watched several esri videos about the topic and in an earlier video it talks about running moran's i autocorrelation to select a suitable distance band, in a more recent video I have watched it talks about calculate distance band and incremental spatial autocorrelation (ISA). I realise they both produce Moran's i z scores but I have run both and get different results so I am not sure which one is better to use. The results from ISA seem to be suggesting higher distance bands (peaking at higher distance values) which means by data is showing large hot spots (more like trends), where as the running Moran's i I see peaks in lower values which produces smaller hot spots. Would it be acceptable to use the calculate distance band and just use the maximum value in Moran's i as this produces a peak in the z score at a smaller distance. For example, the maximum distance is 2.09736dd, and the average is 0.368413dd. Results in ISA peak at 5.04dd and Moran's peaks at the 2.09dd value. Also, the conceptualisation of spatial relationships is to be the same as I am using in the hot spot analysis, yes? Thank you.
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02-22-2012
07:39 AM
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Thanks Luke. I've found the scale factor and the add offset value. What exactly is an add offset value? For my data is 0.0d, does this mean I don't have to do anything?
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02-13-2012
04:10 AM
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Hi, I'm not sure if anyone can help. I am using Modis MOD08_M3 data to look at aerosol data across Brazil. I've managed to load the file/subfile into Arc but I am unsure on the values of the data... I was under the impression the aerosol data had values between 1 and 0, however mine are much different to this. If anyone has experience with this data and know how to get the actual values and/or literature on how to, it would be great to hear from you. Thanks!
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02-10-2012
04:22 AM
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Hi, This is probably very simple to answer. I am running the Hot Spot Analysis for different years to examine any clusters of diseases. I have followed the on line video instruction and was wondering once I have distance band for one year do I use the same for all years or should I run the autocorrelation for each year to find the best distance band? I assume I do that but wasn't sure if it would mean the clusters are not comparable or something similar. Thanks
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02-08-2012
11:56 AM
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OK, so I've read some more and realise now I need to map the residuals. However the ESRI help doesn't specify if it is the std residuals or just the residuals. The image they show is of the std residuals and then talks about running spatial autocorrelation on the regression residuals - I assume it means on those std residuals??
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02-08-2012
12:21 AM
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Hi, I am new(ish) to ArcGIS and haven't done Stat's in a few years so sorry if this seems very simple. I am attempting to explore relationships between respiratory diseases and 3/4 environmental variables over a large area. I have been advised to use GWR and I've read around the subject and it seems appropriate. However, it talks about spatial autocorrelation as well. I am wondering if I am meant to run Moran's i on the original data or on the residual results from GWR? Also, I have been advised I want the Morans i result to be around zero, is this correct? Thank you, Lauren
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02-07-2012
11:41 PM
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