Point Patterns of New Brunswick Forest Fires
Point patterns created from yearly records, provided by the New Brunswick Department of Natural Resources, of all fires falling under their jurisdiction for the years 1987 to 2003 inclusive (with the year 1988 omitted until further notice).
The coordinates of the fire locations were provided in terms of
latitude and longitude, to the nearest minute of arc. These were
converted to New Brunswick stereographic projection coordinates
(Thomson, Mephan and Steeves, 1977) which was the coordinate
system in which the map of New Brunswick --- which constitutes the
observation window for the pattern --- was obtained. The conversion
was done using a
C program kindly provided by Jonathan
Beaudoin of the Department of Geodesy and Geomatics, University of
Finally the data and window were rescaled since the use of the
New Brunswick stereographic projection coordinate system resulted
in having to deal with coordinates which are expressed as very
large integers with a bewildering number of digits. Amongst other
things, these huge numbers tended to create very untidy axis labels
on graphs. The width of the bounding box of the window was made
equal to 1000 (nameless) units. In addition the lower left hand
corner of this bounding box was shifted to the origin. The height
of the bounding box was changed proportionately, resulting in a
value of approximately 959.
The window for the fire patterns comprises 6 polygonal components,
consisting of mainland New Brunswick and the 5 largest islands.
Some lakes which should form holes in the mainland component are
currently missing; this problem may be remedied in future releases.
The window was formed by
[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Note that due to data entry errors some of the
out.julian) were set equal to
NA. Also, some of the
dates and times were missing (equal to
NA) in the original
unknown. Many of the years had most, or sometimes
all, of the ignition source codes equal to 0 (hence turning
unknown, and many of the years had many
missing values as well. These were also assigned the
unknown. Of the 7108 fires in
4354 had an
unknown ignition source. This variable
is hence unlikely to be very useful.
There are also anomalies between
worrisome is the fact that the cause
ltning (!!!) is
associate with sources of ignition
data(nbfires) creates two objects:
nbfires is a marked point pattern (an object of
"ppp") consisting of all of the fires in the years
1987 to 2003 inclusive, with the omission of 1988. The marks
consist of a data frame of auxiliary information about the fires;
see Details. Patterns for individual years can be extracted
using the function
split.ppp(). (See Examples.)
nbw.rect is a rectangular window which covers
central New Brunswick. It is provided for use in illustrative and
The data were kindly provided by the New Brunswick Department of Natural Resources. Special thanks are due to Jefferey Betts for a great deal of assistance.
Point patterns of forest fire locations.
Environmental and Ecological Statistics
16 (2009) 197 -- 223, doi:10.1007/s10651-007-0085-1.
Thomson, D. B., Mephan, M. P., and Steeves, R. R. (1977)
The stereographic double projection.
Technical Report 46, University of New Brunswick,
Fredericton, N. B., Canada
data(nbfires) # Get the year 2000 data. X <- split(nbfires,"year") Y.00 <- X[["2000"]] # Plot all of the year 2000 data, marked by fire type. plot(Y.00,which.marks="fire.type") # Cut back to forest and grass fires. Y.00 <- Y.00[marks(Y.00)$fire.type %in% c("forest","grass")] # Plot the year 2000 forest and grass fires marked by fire duration time. stt <- marks(Y.00)$dis.julian fin <- marks(Y.00)$out.julian marks(Y.00) <- cbind(marks(Y.00),dur=fin-stt) plot(Y.00,which.marks="dur") # Look at just the rectangular subwindow (superimposed on the entire window). nbw.mask <- as.mask(nbfires$window, dimyx=500) plot(nbw.mask, col=c("green", "white")) plot(nbfires$window, border="red", add=TRUE) plot(Y.00[nbw.rect],use.marks=FALSE,add=TRUE) plot(nbw.rect,add=TRUE,border="blue") # Look at the K function for the year 2000 forest and grass fires. K.00 <- Kest(Y.00) plot(K.00)