Questions tagged [stars]

The R package providing classes and methods for reading, manipulating, plotting and writing spatiotemporal data cubes.

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How to properly save netCDF file with stars

I'm trying to save properly formatted stars object to netCDF file with no success. Here is a reproducible example of what I'm doing. library(tidyverse) library(stars) # example data ex <- tibble(...
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Apply function at grid cell level across layers of a raster file

I have a netcdf raster object with multiple layers (time: 30 years * 12 month = 360 steps). The raster is constituted of multiple grid-cells (say 1000). I want to linearly detrend each month ...
1 vote
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Recursively mosaic rasters by directory (year) in R

I have hundreds of rasters spanning 10 years, files are stored by year (e.g., 2020, 2019, 2018, etc.). I would like to mosaic all the raster files within a directory, move to the next directory and ...
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NAs when calculating the mean of raster values per polygon using R (stars & sf)

I am trying to get the mean NDVI value for tree clusters (I've calculated them using DBSCAN) using stars and sf but, I'm getting a lot of NA values, which they don't appear if I use the Zonal ...
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2 votes
1 answer
159 views

Mask a (raster) stars object in R with a vector (sf) object

In this question an stars object is masked with a raster object. But it is not clear to me how the masking can be done with a vector object using the stars pkg. Consider the following example in terra....
3 votes
2 answers
128 views

What's the most efficient way to calculate line length per raster cell in R?

Problem I'm looking for an efficient, memory friendly to calculate total line (vector data) length per raster cell. The question of line length per cell has already been posed here in 2014 and a few ...
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2 votes
2 answers
230 views

Calculate area weighted mean values of polygons for raster cells using R

Problem I want to rasterize polygon values and assign their weighted mean to raster cells. Weighting should be done based on the polygons' cell coverage. Problem visualized Calculation for grid cell ...
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3 votes
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How to apply mean/min/max merge functions on a vector layer to create a stars raster?

Problem I would like to stars::st_rasterize a vector layers of an sf object using aggregation functions such as mean/median/max/min. raster::rasterize lets me use mean, min etc. and even define ...
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1 answer
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R stars read_ncdf returns "vector memory exhausted (limit reached?)" when proxy = TRUE

My question involves an error when trying to read a large dataset, so I'm not sure of the best way to provide a reproducible example. I am trying to read a large netcdf file into R as a stars proxy ...
3 votes
1 answer
350 views

Rasterizing and resampling a vector object using stars::st_rasterize() and terra::rast() loses values/data

I am currently struggling with rasterizing and later, resampling a vector object using functions from stars and terra. Let's start with the example dataset here: https://drive.google.com/drive/u/2/...
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1 vote
1 answer
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Comparing polygon areas across simple feature collections

I currently have three simple feature objects created from different shapefiles in R using the sf package. These three objects have all been projected to the same coordinate system using st_transform()...
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1 answer
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Add a calculated band to a R stars object

I use R stars package "read_stars" function to open sentinel bands files yielding the following object (Sentinel): stars object with 3 dimensions and 1 attribute attribute(s): ...
1 vote
2 answers
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Is there an equivalent of "isLonLat" function in terra package in R?

I am refactoring my code which extensively relied on raster package to now use the newer and better terra package. I was making use of the isLonLat() function that returns TRUE if the crs of a raster ...
1 vote
1 answer
134 views

Expand stars-raster in R

In the r-package terra there is the function terra::extend. To my understanding it just expands the raster with no data values on each side right? I wanted to do something similar, but using a stars ...
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1 answer
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Fix NetCDF dimensions of stars object

I downloaded some CMIP6 data from Copernicus data service and I believe the NetCDF file came with malformed dimension information. When I try to get the lon or lat dimensions (st_get_dimension_values) ...
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1 answer
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Summarise R stars objects by group

I would like to summarise the bands of a stars object using a band as a grouping variable. In this small example, I have two bands with information on e.g. species densities. In addition, I have a ...
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1 vote
1 answer
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stars: add band based on existing band calculations

I would like to add an additional band to a stars object that includes information from two existing bands. library(stars) library(tidyverse) toy_data <- reduce(rerun(2, { m <- matrix(sample(...
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st_as_sf() of stars object reduces the object extent

I am attempting to do a raster to polygon conversion using the stars package. The workflow i've seen elsewhere (and have used successfully previously) is on my "zones" raster is: zones_stars ...
3 votes
1 answer
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Convert long datframe in R with each band being in one column to stars object with band as dimension

So I have a dataframe that looks like this: x y band val <dbl> <dbl> <int> <dbl> 1 12.5 48.7 1 0 2 14.3 47.3 1 0 3 10.3 48.0 1 0 4 ...
1 vote
1 answer
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Reprojected data from stars R package takes forever with geom_stars and ggplot2

I'm finding very different plotting results with stars objects after I reproject them and use ggplot2. Consider the following: library(stars) library(ggplot2) system.file("tif/L7_ETMs.tif", ...
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How to test whether the argument passed to an R function is a raster or a vector

I am writing a function that expects two arguments: X and Y. Argument X should be a raster which can be generated by packages such as raster, terra, or stars. Argument Y should be a polygon from ...
0 votes
1 answer
422 views

Mask a stars object in R

I am trying to mask a stars object in R, but not sure how to do it. The documentation here says that mask in Raster can be done as [] <- in stars. I am not sure what this means. Here is code from ...
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sf st_make_valid silently failing after st_combine

I'm trying to create an object of class 'sf' that is single multipolygon out of a raster. I'm following the procedure in this SE post: https://gis.stackexchange.com/a/357792/191148, but I want to keep ...
2 votes
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Merge single- and multi-band rasters with stars

I can easily use c() to merge two single band rasters or two multi-band rasters using the R package stars, however, when I try merging a single band raster with a multi band raster, I get the error ...
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5 votes
1 answer
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Plot two layers (raster and polygon-vector) with ggplot and use the fill-scale* for both layers

I am a little lost. I have a stars object where I would like to use the first attribute and map it to the scale_fill*-function in ggplot. I also have an polygon-object of class sf that has an ...
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Combine named list of stars object into one new stars object with the names being a new dimension

I have a list of stars objects that I created in a loop. This little example is more or less replicating my situation. library(stars) tif = system.file("tif/lc.tif", package = "stars&...
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1 vote
1 answer
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Handle Curvilinear/rotated grid NetCDF file in R

I have a NetCDF file with a curvilinear (rotated) grid that contains meteorological data. I am trying to crop the NetCDF based on a mask shapefile in R, but the rotated grid does not project the data ...
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206 views

Compute mean of two stars objects in R

I have two stars-objects and I simply would like to calculate the mean for each pixel. I am not really sure how to do that and if my approach is correct. At the moment I'm doing the follwing: I have &...
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Generating Kernel density raster/stars with same dimensions

I would like to generate different rasters from kernel density functions with the same resolution, so that I can compare them. Take this example from here: library(MASS) library(raster) set.seed(123); ...
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1 vote
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Focal operations / aggregations on stars_proxy object in R

I have many NetCDF-files that I read in as stars_proxy-object. I also have a geopackage that is a multipolygon. I Would not like to extract the mean value for each polygon for each stars_proxy-object. ...
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1 vote
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Difference in CRS when reading with read_stars und read_ncdf

I have a NetCDF file that I would like to load into a stars object. The two functions st::read_stars and st::read_ncdf both load it in, but the data ends up in different locations when I plot it using ...
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1 vote
1 answer
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What is the canonical way to perform raster calculations using R stars?

I have a data cube that I am handling in the R stars package. It has 3 dimensions (latitude, longitude and time) and 2 attributes (northwards and eastwards components of wind). A dummy equivalent ...
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abind Error when converting a .tif raster data object to an sf object using st_as_sf() in R

When I try to convert a .tif raster data object to an sf object using st_as_sf() in R, I get the following error: Error in abind(x, along = length(dim(x)) + 1) : along must be between 0 and 2 Does ...
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2 votes
1 answer
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Why krige function return all NA's values for the prediction when trying to interpolate a variable?

I am trying to build a map with kriging interpolation for a variable. When running the krige function the return is all NA values and the kriged map plot only one value. I couldn't find out why and I ...
1 vote
0 answers
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Getting an sf boundary of a raster or stars object

I am trying to figure out the best approach to convert an raster or stars object into its boundary returned as an sf object. I think I have a pretty decent handle on how to do it with raster (shown ...
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1 vote
1 answer
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Convert large stars object to sf object

My ultimate goal is to convert landcover raster (.tif) objects to an sf object representing the raster's grid and the original values of each cell within each geometry. I have been able to do this for ...
2 votes
1 answer
271 views

Temporal rolling mean in stars

I need to find temporal rolling means (or other stats - max, min, etc.) in stars spatial obects. For stars raster cubes, this would be directly analogous to the calc(rasterBrick, function(x) movingFun(...
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Error while converting raster to ploygon using stars package

I am trying to convert raster to polygon using stars package as suggested in this and this. I have used the following code library(raster) library(stars) library(sf) library(magrittr) #read raster r1&...
1 vote
1 answer
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Exporting ASCII file from 'stars' package

I'm playing around with the stars package (0.4-1) in R, but I can't get how to export a grid object in ASCII format, as the traditional writeRaster(r, filename=file.path(dir.list[j], 'test.asc'), ...
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2 votes
1 answer
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Raster file statistics in R (stars and raster package) don't match gdalinfo

I'm trying to read a gridded binary file in R using read_stars. Comparing the stats from stars package to the stats from gdalinfo, I could see differences in min/max values. Below is the sample code. ...
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1 vote
1 answer
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Read NetCDF file with read_stars in R

I am trying to work with cordex climatic data (curvelinear and rotated data) in the stars package, and I am having a lot of issues, so decided to simply reproduce online example, and I fail reading in ...
6 votes
2 answers
236 views

Generate a stars object from tabular spatial temporal data?

I have tabular data with columns longitude, latitude, time, and intensity, like so: library(lubridate) ## mock example data ex <- tibble(longitude = 1:10, latitude = 10:1, ...
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2 votes
1 answer
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r stars: calculate ndvi for every time step on stars proxy

I would like to calculate the ndvi on every time step of a 4d data cube (x, y, bands, time) in on an stars proxy object. Do you have any ideas of how to achieve this on the proxy object? My current ...
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1 vote
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Copernicus ERA5 crs/projecition for NetCDF

i'm trying to work from netCDF from this link: https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=form but i can't find the correct EPSG. In documentation page i ...
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4 votes
1 answer
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stars package in R. How to add time dimension in a stars object?

I have a raster stack (my_stack) and I converted it into a stars object: mystar <- st_as_stars(my_stack) That results in: stars object with 3 dimensions and 1 attribute attribute(s), summary of ...
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2 votes
1 answer
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Stratified ordinary kriging using gstat and stars packages

The gstat package supports stratified ordinary kriging using sp objects as shown at https://github.com/r-spatial/gstat/blob/master/demo/examples.R (the code below). This year (https://r-spatial.github....
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1 vote
2 answers
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NetCDF time aggregation using R stars package

I have a monthly temperature netCDF dataset with aprox 20 years and I'd like to calculate a monthly climatology (average of all Jan, Feb, Mar...). I know I can do this with stackapply from package ...
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4 votes
1 answer
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Convert XYZ to stars curvilinear grid and plot

I have data in XYZ format (long, lat, elevation) that does not fit on a rectangular grid, but I would like to plot it as grid cells of different sizes. To illustrate what I mean, the last two plots ...
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1 vote
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Creating map projection for net of geodesic dome?

I am working on a project that involves mapping the night sky's northern hemisphere onto the exterior surface of a small (16 cm radius) geodesic dome. The problem is, I don't know what map projection ...
1 vote
0 answers
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R stars package and set dimensions to a NetCDF file

Related: GDAL and reprojecting a NetCDF file Following above, I would like to reproject a NetCDF ( NOAA GOES-16 file ) using R stars package. However, I have been unsuccessful at the first step; I ...
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