inst/dev/tidync-filtrate.R

In r-gris/ncdump: Extract Metadata from 'NetCDF' Files as Data Frames

cls <- c("#440154FF", "#471164FF", "#482071FF", "#472E7CFF", "#443C84FF", 
"#3F4889FF", "#39558CFF", "#34618DFF", "#2F6C8EFF", "#2A768EFF", 
"#26818EFF", "#228B8DFF", "#1F958BFF", "#1FA088FF", "#24AA83FF", 
"#30B47CFF", "#41BD72FF", "#57C666FF", "#6FCF57FF", "#8AD647FF", 
"#A7DB35FF", "#C4E021FF", "#E2E418FF", "#FDE725FF")
library(ncdump)
f <- "/rdsi/PRIVATE/raad/data/eclipse.ncdc.noaa.gov/pub/OI-daily-v2/NetCDF/2017/AVHRR/avhrr-only-v2.20170502_preliminary.nc"
x <- NetCDF(f)
x
nctive(x)
## push sst to the front for an extraction
x <- activate(x, "sst")
hyper_slab <- filtrate(x, lon = lon > 100, lat = lat < 30)
## it's alive, test the extraction
library(ncdf4)
nc <- nc_open(f)
library(dplyr)
sst <- ncvar_get(nc, "sst", start = bind_rows(hyper_slab)$start, count = bind_rows(hyper_slab)$count)
image(sst, col = cls)
## push a different var to the front
x <- activate(x, "anom")
hyper_slab <- filtrate(x, lon = between(lon, 147, 250), lat = between(lat, -42, 20))
anom <- ncvar_get(nc, "sst", start = bind_rows(hyper_slab)$start, count = bind_rows(hyper_slab)$count)
image(anom, col = cls)