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I have found a lot of questions about conversions of Northings/Eastings to Longitude/Latitude in R. I have been working with this tutorial from Alex Singleton which is really useful in explaining the process and giving sample code. I have adapted the code for my own CSV file, and worked through the steps. My issue is, when i plot the data onto the map, it plots accurately in relation to each other, but does not plot over Northern Ireland, instead plots relational to eachother, but floating over wales.

map with plot

Is there a simple fix for this to shift the plot?

setwd("~/R/maps")
ukgrid = "+init=epsg:27700"
latlong = "+init=epsg:4326"
holes <- read.csv("Pothole_Enquiries_2016.csv", header = TRUE)
map <- readRDS("GBR_adm2.rds")
plot(map, col = 'grey', border = 'darkgrey')
holes <- subset(holes, select = c("EASTING","NORTHING"))
holes$holes_ID <- 1:nrow(holes)
coords <- cbind(EASTING = as.numeric(as.character(holes$EASTING)),NORTHING = as.numeric(as.character(holes$NORTHING)))
holes_SP <- SpatialPointsDataFrame(coords, data = data.frame(holes$holes_ID), proj4string = CRS("+init=epsg:27700")
holes_SP_LL <- spTransform(holes_SP, CRS(latlong))
points(holes_SP_LL,col=2,pch=18)

I am presuming that this is something to do with the UKGrid codes, but i have only started to use spatial plots so this is a little new to me.

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EPSG:27700 is the Great British Grid and as such doesn't include Northern Ireland. Your coordinates are most likely on the Irish Grid EPSG:29903 which should fix your issue.

It won't help with your Null Island issues but will move them from the British Null Island (near the Scilly Islands) to the Irish one.

  • That's great @iant I knew it was something simple but only starting to use geospatial plots – Alan_Hook Oct 18 '17 at 13:14

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