Hello,
I have count data that illustrate the presence or absence of individuals in
my study population. I created a grid cell across the study area and
calcuated a count value for each individual per season per year for each
grid cell. The count value is the number of time an individual was present
in each grid cell. For illustration my data columns look something like
this and are repeated for each individual:
Cell_ID Param1 Param2 Param3 Param4 COUNT Name Year Season Cov
1 160.565994 729.08 1503 7930.3 0 AA 2010 AUT
Open
1 160.565994 729.08 1503 7930.3 22 AA 2011 SPR
Open
1 160.565994 729.08 1503 7930.3 12 AA 2009 SUM
Open
1 160.565994 729.08 1503 7930.3 0 AA 2010 SUM
Open
2 169.427001 491.87 1503.31 5101.09 0 AA 2010 AUT
oldHard
2 169.427001 491.87 1503.31 5101.09 16 AA 2011 SPR
oldHard
2 169.427001 491.87 1503.31 5101.09 0 AA 2009 SUM
oldHard
2 169.427001 491.87 1503.31 5101.09 0 AA 2010 SUM
oldHard
…
563 86.777099 612.69 977 4474.6 62 AA 2010 AUT
Water
563 86.777099 612.69 977 4474.6 12 AA 2011 SPR
Water
563 86.777099 612.69 977 4474.6 55 AA 2009 SUM
Water
1 160.565994 729.08 1503 7930.3 0 BB 2010 SUM
Open
2 169.427001 491.87 1503.31 5101.09 72 BB 2010 SUM
oldHard
5 160.75 614.95 1503.31 2878.98 16 BB 2010 SUM medHard
6 170.404998 510.58 1489.44 743.14 0 BB 2010 SUM
Water
…
563 86.777099 612.69 977 4474.6 0 BB 2010 SUM
Water
1 160.565994 729.08 1503 7930.3 14 C 2005 AUT
Open
1 160.565994 729.08 1503 7930.3 0 C 2006 AUT
Open
1 160.565994 729.08 1503 7930.3 0 C 2006 SPR
Open
1 160.565994 729.08 1503 7930.3 56 C 2007 SPR
Open
1 160.565994 729.08 1503 7930.3 0 C 2006 SUM
Open
2 169.427001 491.87 1503.31 5101.09 124 C 2005 AUT
oldHard
2 169.427001 491.87 1503.31 5101.09 231 C 2006 AUT
oldHard
2 169.427001 491.87 1503.31 5101.09 889 C 2006 SPR
oldHard
2 169.427001 491.87 1503.31 5101.09 0 C 2007 SPR
oldHard
…
563 86.777099 612.69 977 4474.6 0 C 2005
AUT Water
563 86.777099 612.69 977 4474.6 231 C 2006
AUT Water
563 86.777099 612.69 977 4474.6 185 C 2006
SPR Water
563 86.777099 612.69 977 4474.6 123 C 2007
SPR Water
563 86.777099 612.69 977 4474.6 52 C 2006
SUM Water
I have 563 grid cells across my study area and each individual has 1-563
cells associated for each year and each season the individual was monitored.
Therefore my grid cells are repeated. I end up with 71,000 records and 925
records have a Count value >0; which means 70,075 records have a Count value
= 0.
I wanted to run a zero inflated poisson model to determine mixed effects (of
parameters) with individual as the random effect. But I have been advised
two things:
1. I cannot run a zero inflated poisson model because my data are too
"extremely" inflated (i.e. 70,075 vs 925) and
2. I cannot run the model with each cell repeated for each individual. I am
told the model doesn't recognize that Cell_ID #1 for individual "A" is the
same Cell_ID #1 for individual "B".
Does anyone know if either or both of these points are true? I would
appreciate any thoughts, advice, or suggestions.
Thanks!
-Stephanie
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