I'm having trouble merging two raster datasets that have different resolution and extent, and have irregular point data. Below is info on each raster. I need these datasets to merge according to the grid points so that I can run a fire spread model (which requires both wind and slope data).
I have tried converting to normal dataframes (using rasterToPoints) before merging but the differences lead to loss of a lot of grid points.
I have tried to align the rasters with project raster and rasterize, but I haven't managed to get it to work. If anyone has an idea that could help, I would really appreciate your answer!
'''
Data from https://globalwindatlas.info/downloads/gis-files
> wind <- raster("ZAF_wind-speed_10m.tif"); wind
class : RasterLayer
dimensions : 11271, 11804, 133042884 (nrow, ncol, ncell)
resolution : 0.0025, 0.0025 (x, y)
extent : 13.33407, 42.84407, -50.31423, -22.13673 (xmin, xmax, ymin, ymax)
crs : +proj=longlat +datum=WGS84 +no_defs
source : C:/Users/s2000128/Documents/Flammability modelling/ZAF/ZAF_wind-speed_10m.tif
names : ZAF_wind.speed_10m
Data from https://datacatalog.worldbank.org/dataset/world-slope-model
> slope <- raster("ZAF1_msk_alt.grd"); slope
class : RasterLayer
dimensions : 1548, 1992, 3083616 (nrow, ncol, ncell)
resolution : 0.008333333, 0.008333333 (x, y)
extent : 16.4, 33, -34.9, -22 (xmin, xmax, ymin, ymax)
crs : +proj=longlat +ellps=WGS84 +no_defs
source : C:/Users/s2000128/Documents/Flammability modelling/slope_deg_0/slope_deg/ZAF1_msk_alt.grd
names : ZAF1_msk_alt
values : -26, 3264 (min, max)
Here are some examples of what I have tried:
1
windresampled <- projectRaster(wind,slope,method = 'ngb'); windresampled
2
wind_points <- rasterToPoints(wind);
coordinates(wind_points) = ~x+y;
proj4string(wind_points) = CRS("+init=epsg:4326");
gridded(wind_points) = TRUE;
g_wind <- raster(wind_points); g_wind;
extent(wind) <- c(16.4,33, -34.9,-22);
res(wind) <- c(0.0025, 0.0025);
r_wind <- rasterize(wind_points, g_wind, field = wind_points$z, fun = mean, na.rm = TRUE); r_wind
