Hello, As far as I understand, for one point (i.e., one row of the sf/data.frame) you have several precipitation values, but can calculate one exceedance probability from these values. So an xy-plot is not the best choice for visualization of this kind of data. Or you'll have the same y value (probability) for several x values (precipitation). If this is not a problem for you, then I suggest using tidyr::pivot_longer() to transfrom the precipitation values from the several columns to one. Then you can draw the xy-plot by ggplot or base plot or even lattice plot. HTH, Ákos __________ Ákos Bede-Fazekas Centre for Ecological Research, Hungary
2023.02.16. 2:52 keltezéssel, rain1...@aim.com írta: > Hi Akos, > > Thank you so much for this suggestion! Indeed, I have 25 data points > in each column, and yes, the data are normally distributed. Using the > pnorm function is actually quite useful, as well. To that end, could > the values of exceedance probability from pnorm be somehow plotted > against their associated precipitation thresholds on an xy plot, for > example? > > Another idea that came to mind is the use of Probability Density > Functions, but can these really be used to graphically show exceedance > probabilities? > > Thanks, again! > > -----Original Message----- > From: Bede-Fazekas Ákos <bfalevl...@gmail.com> > To: r-sig-geo@r-project.org > Sent: Wed, Feb 15, 2023 1:59 am > Subject: Re: [R-sig-Geo] Plotting probability exceedance > > Hello, > > You should know or make assumptions on the distribution of the > precipitation. Let's say it is normally distributed (i.e. bell-shaped). > Then you can calculate the probability of exceeding the quantile /q/ by > pnorm(q, mean, sd, lower.tail = FALSE). > If you have several spatial points and a lot of measurments (stored in > columns of the sf/data.frame) for each of the points, then use > apply(X, MARGIN = 1, FUN = function(measurements) {return(pnorm(q, mean, > sd, lower.tail = FALSE))}) > and you can display the probabilities in a map. > > HTH, > Ákos > __________ > Ákos Bede-Fazekas > Centre for Ecological Research, Hungary > > 2023.02.15. 1:28 keltezéssel, rain1290--- via R-sig-Geo írta: > > Hi there, > > I have climate data pertaining to extreme precipitation, as well as > carbon emissions associated with those precipitation values in a > dataframe. > > The goal of my analysis would be to determine the probability of > exceeding specific thresholds of precipitation extremes, as well as > showing this graphically (I am imagining this by placing extreme > precipitation on the the x-axis and exceedance probabilities on the > y-axis). > > My question is if anyone has an idea how to approach this, or a good > starting place? I have looked online, but there is nothing specific to > really draw on. > > Thank you for your time, and I look forward to your response! > > [[alternative HTML version deleted]] > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@r-project.org > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo