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Hi Carl, thank you, I was able to use the expression - appreciate the help!
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07-30-2015
12:44 PM
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Hi Dan, In response, yes, there is great variation in the points over time, as I am measuring the frequency of fishing in certain ocean areas. What I have is the average number of times a fishing vessel entered a certain area, which was averaged over a 5-year period. I am trying to find out the magnitude and direction of the trend. Perhaps there is a better way to go about this?
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07-28-2015
07:38 PM
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Thank you Carl, that is helpful. What I have is the average number of times a fishing vessel entered a certain area, which was averaged over a 5-year period. What I wanted to find was the coefficient, to see if the trend is increasing or decreasing over time - e.g. is the polygon becoming more of less valuable to fishing vessels over time. I have over 4,000 polygons so cannot do this manually, so wanted to set up an automated process - I tried the OLS in arc but not sure I am understanding the outputs. I am not trying to conduct a multiple regression, I just wanted to know the direction and magnitude of the trend. Should the OLS tool do this for me?
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07-28-2015
07:14 PM
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Yeah, that's what I was thinking I might have to do. I know I have seen some people complete regressions in arcgis, and was hoping there might be a way to set this up.
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07-28-2015
01:45 PM
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I have a large dataset where I have summed point values in polygons. I have a separate value per year, over five years. I want to find the trend in each polygon over time. I'd like to set up a regression to find the coefficient for change (positive or negative trend) in each polygon, but can't figure out how to set this up. Any suggestions? Thanks!
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07-28-2015
01:26 PM
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Hi, Once I used both in the case field, it worked. Using only one case field, it didn't give me a unique line for each vessel and poly. Thanks for your help!
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07-20-2015
11:09 AM
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Ah, that worked! THANK YOU!! I have been trying different tools for days. Using the two steps, I get exactly what I needed.
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07-20-2015
11:03 AM
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I did try that, but what it gives me is the total count of vessel activity in the cell, but not separated by unique vessels. For example, polygon "A" has 5 point records associated, and the statistics output was 5. however, when i look at my attribute table, only two vessels are associated: one vessel went twice, and the other went three times. So I cannot show this data. I need it to show the number of unique vessel IDs per polygon.
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07-20-2015
10:41 AM
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Hi, I am trying to build a query that tells me the number of unique vessels that entered a specific polygon. Each vessel may have gone to several polygons and visit each or any polygon multiple times. I am limited by confidentiality to only display the polygons that have 3 or more unique vessels that went there. I have tried a multitude of tools, but I think what I need is to build a query. Any idea how to build this? I have intersected the points (each record of a vessel) with the polygons, the intersection output is in a point shape file. Thank you!
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07-20-2015
10:24 AM
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