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Below is a list of 3 point patterns with measured tree data.

ppp_list
[[1]]
Marked planar point pattern: 3 points
Mark variables: SPCD, DIA, HT 
window: polygonal boundary
enclosing rectangle: [-9215316, -9215301] x [8549428, 8549443] units

[[2]]
Marked planar point pattern: 4 points
Mark variables: SPCD, DIA, HT 
window: polygonal boundary
enclosing rectangle: [-8942245, -8942230] x [8838323, 8838337] units

[[3]]
Marked planar point pattern: 7 points
Mark variables: SPCD, DIA, HT 
window: polygonal boundary
enclosing rectangle: [-8320491, -8320476] x [9268799, 9268813] units

Below are the covariates that I am adding to be included in the hyperframe.

temp <- c(50.75,65.75,48)

prec <- c(85.75,56.42,38.25)

myhyperframe <- hyperframe(trees=ppp_list, temp=temp, prec=prec)

Below is the structure of my hyperframe.

Hyperframe:
  trees  temp  prec
1 (ppp) 50.75 85.75
2 (ppp) 65.75 56.42
3 (ppp) 48.00 38.25

When I tried to run a point process model using the "mppm" function, it comes up with an error saying that my point pattern is not multitype. I am unsure if I am approaching running point process models correctly. The "mppm" function works for the dataset "simba" and when I made the "waterstriders" dataset a hyperframe.

mppm(trees ~ 1, myhyperframe)
# Error in (function (data, dummy, method = c("grid", "dirichlet"), ...)  : 
#             data pattern is not multitype

Any feedback would be great. Thank you!

Taylor R Brown
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1 Answers1

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This is not a problem of formatting.

mppm and ppm do not yet support the analysis of point patterns with multiple columns of marks, or point patterns with continuous numeric marks.

The error message says that the point pattern is not multitype. A multitype point pattern is one which has a single column of marks, which are a factor.

You can either remove the marks, or convert them to a factor, before applying mppm.

Adrian Baddeley
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