quadracount on multitype points

Hi Guy,

Maybe your explorative analysis could also benefit from `relrisk` in 
case you don't know that function?

It basically gives you a list of smooth images (one for each type) of 
the probability that a hypothetical sample at that location is of a 
given type. E.g. for the built-in multitype point pattern dataset 
`lansing` you would do:

??? library(spatstat)
??? prob <- relrisk(lansing, diggle=TRUE)
??? plot(prob)

This example and more (e.g. a division of the sampling area into 
subsets of dominant types) can be found in Chapter 14 of our "spatstat 
book" if you need more details (sorry about the shameless self 
promotion, but I don't know a better source for this :-)).

Kind regards,
Ege

On 09/13/2017 01:08 AM, Guy Bayegnak wrote:

Thanks a lot for your response and suggestion Rolf.? Yes, by 
"quadrant" I mean the little sub-windows.? My problem is the following:

We have collected thousands of groundwater samples across a vast 
area, and analysed them. Based on the analysis we are able to assign 
a "type" to each water sample.? When plotted, there seems to be a 
spatial trend in water type. But a given area may have more than one 
water type,? usually with a dominant type (most frequently 
occurring). What I am trying to do is identify the dominant type for 
each sub-region /sub-windows but show the count side by side, for 
example:

?????????? x
? y???????? [0,0.801)??????????? [0.801,1.6]
?? [0.5,1]?? Off =???? 36??????????????? Off =? 6
??????????? On =?? 3???? On = 39

??? [0,0.5)?? Off =? 4????????????? Off = 36
???????????? On = 42??????? On = 6

I think I can achieve what I am looking for with your suggestion. 
Once I get the table list, I will copy the numbers side by side 
manually.

Sincerely,

Guy

-----Original Message-----
From: Rolf Turner [mailto:r.turner at auckland.ac.nz]
Sent: September 12, 2017 3:45 PM
To: Guy Bayegnak <Guy.Bayegnak at gov.ab.ca>
Cc: r-sig-geo at r-project.org; Adrian.Baddeley at curtin.edu.au; Ege Rubak 
<rubak at math.aau.dk>
Subject: Re: [R-sig-Geo] quadracount on multitype points


On 13/09/17 02:11, Guy Bayegnak wrote:

Dear all,

I am working on a multitype point pattern, and I'd like to estimate
how many of each type of point occurs into each quadrant. I know it is
possible to use the quandracount on split marks as follows using
spatstats: quadratcount(split(marks)). But the result produces as many
windows as they are marks. I am wondering is there is a way to know
many occurrence of each type there is per quadrant and to plot it in a
single grid.

Thanks.

You really should start by mentioning that you are dealing with the 
spatstat package.

It's not clear to me what you are after.? A minimal reproducible 
example would be helpful.? I presume that by "quadrant" you mean one 
of the four equal sub-windows formed by bisecting your (rectangular) 
window vertically and horizontally.

If my presumption is correct then perhaps

????? lapply(split(X),quadratcount,nx=2)

(where "X" is your point pattern) does what you want.? E.g.:

lapply(split(amacrine),quadratcount,nx=2)
$off
????????? x
y???????? [0,0.801) [0.801,1.6]
?? [0.5,1]??????? 36????????? 36
?? [0,0.5)??????? 34????????? 36

$on
????????? x
y???????? [0,0.801) [0.801,1.6]
?? [0.5,1]??????? 35????????? 39
?? [0,0.5)??????? 42????????? 36

Is this something like what you wish to achieve?

cheers,

Rolf Turner

-- 
Technical Editor ANZJS
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University of Auckland
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