What is the proper input field for clacualting Moran's I?

[MelAgapito]

I am trying to use Arcgis in calculating Moran's I. I get an error and I am thinking that it might be due to the nature of my input field. After reading some documentation from ESRI website, it seems to me that the input field must be a weighted value of incident or event. What I have is a point dataset containing about 13,000 data points. Each point has a field containing the total count of fish observed per sampling. I used this field as the input field in calculating Moran's I and it returns an error. I am not sure if I need to calculate a weighted value for each of the total count. If yes, I am not sure exactly how this weighted value should be calculated. Any advice would be greatly appreciated.

[DavidBirkigt]

Most calculations of moran I require a weight matrix. There are a lot of different types, but they all essentially describe the spatial/neighbourhood relationship found in your data. This is probably what the documentation is referring to.

Some of the arcGIS  calculations of Moran I do not require the input of a weight matrix (probably makes one of the fly).

For row standardization, you do not always need to do this as it depends on your sampling scheme. If you are doing analysis on something like accidents it does not make sense to correct for the spatial relationship of accident sites as they physically happened there (not sampled). Your fish data would be based on a sampling scheme and thus your analysis should be row standardized (ArcGIS), you could have picked a different site and your distribution is likely not uniform in space.

Regardless you should not need to change your data values as moran I is testing to see if similar values of in your case fish catch are found in similar areas. I have always felt non-confident about moran in arcgis and usually calculate it in GEODA. It is free software. You will need to calculate a weight matrix first (can be done in geoda) then perform your moran, there is documentation.  http://www.s4.brown.edu/s4/training/modul2/GeoDa2.pdf

If you are bent on completing your anlysis in arcGIS, provide your error and I might be able to help with that.

David