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mdsumner/spilhaus_proj.md

Last active February 18, 2025 22:18
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spilhaus_proj.md 
dsn <- "/vsicurl/https://projects.pawsey.org.au/idea-gebco-tif/GEBCO_2024.tif"

library(terra)
r <- rast(ext(-1, 1, -1, 1) * 6378137 * 1.9, res = 25000, crs = "+proj=spilhaus")
geb <- project(rast(dsn), r, by_util = TRUE)


cst <- as.contour(geb, levels = 0)

xy <- terra::project(xyFromCell(geb, 1:ncell(geb)), to = "EPSG:4326", from = crs(geb))
lon <- setValues(geb, xy[,1])
lat <- setValues(geb, xy[,2])

plot(geb)
plot(cst, add = TRUE)

lon2 <- lon

lon[abs(lon) > 170] <- NA
contour(lon, add = TRUE, levels = seq(-170, 170, by = 15), lty = 2)
lon2[lon2 < 0] <- lon2[lon2 < 0] + 360
contour(lon2, levels = 180, add  = T, lty = 2)

contour(lat, add = TRUE, levels = seq(-80, 80, by = 20), lty = 2)

image

@Maschette
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Maschette commented Feb 18, 2025 •
edited
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Damn that is pretty.
spil_map package?

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