CODEWITHSUNDEEP
polygonspatialpointspatstat
Ichsan
Ichsan

Reputation: 828

vector shp point to ppp spatstat with polygon windows

I always get error to this

# polygon that to be window
neighborhoods <- st_read("neighborhoods/neighborhoods.shp")

# convert CRS to planar projection as recommended by (https://stackoverflow.com/questions/59597078/use-sf-polygon-object-as-window-in-spatstat)
neighborhoods_3857 <- st_transform(neighborhoods, crs = 3857)

# point that to be PPP spatstat
trees <- st_read("trees/trees.shp")

# convert to planar projection
trees_3857 <- st_transform(trees, crs = 3857)

The problems, the "trees_3857" doesn't have dataframe columns that represent in EPSG3857 coordinates, so Feature column of "trees_3857" doesn't have x and y columns that respect to EPSG 3857

q <- ppp(x=?, y=?, win=neighborhoods_3857)

what I have done but error

z <- as.ppp(trees_3857, win=neighborhoods_3857)
Error in as.ppp.sf(trees_3857, win = neighborhoods_3857): unused argument (win = neighborhoods_3857)
Traceback:

You can get the data freely from datacamp.

https://assets.datacamp.com/production/repositories/738/datasets/96a72364e69d872645038b3a6dc7c0dbcb1114d6/neighborhoods.zip

https://assets.datacamp.com/production/repositories/738/datasets/08a3684dc4d538d59ba051a64a834166883ab5d1/trees.zip

Upvotes: 0

Views: 282

Answers (1)

Adrian Baddeley
Adrian Baddeley

Reputation: 1984

Although you're wanting to transform your data into an object of class "ppp" from the spatstat package, the error message indicates that the problem originated in the function as.ppp.sf which is part of the sf package.

The error message says unused argument: win which means that the function did not recognise or accept the argument win.

Just to make it more challenging, the function as.ppp.sf is not documented and is not visible... By typing sf:::as.ppp.sf we can see the function body and figure out that the function has only one argument, so it does not accept any window information.

This is not the way the generic function as.ppp is designed to work in the spatstat package, so if you looked for help(as.ppp) in spatstat, it's not surprising that you got confused.

The best solution is (as Ege Rubak suggests) to convert the point coordinates and then add the window information:

z <- as.ppp(trees_3857)
Window(z) <- as.owin(neighborhoods_3857)

The conversions as.ppp and as.owin will be executed using code in sf so I can't guarantee they will work. The assignment Window(z) <- will be executed in spatstat code, see help("Window<-.ppp").

Upvotes: 2

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