Datos raster en R
Julian Malpica
22.10.2025
De que trata este cuaderno
Este cuaderno de R ilustra funcionalidades del paquete terra, sf, y RasterVis, para realizar recortes de elevaciones. También aprendimos a hacer ploteos ordinarios y ploteos elegantes. aprendimos que no hay que creer en todos :p
TITULO DE NIVEL 2
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TITULO DE NIVEL 3
library(terra) #archivos raster## terra 1.8.54library(rasterVis) #visualizacion raster## Cargando paquete requerido: latticelibrary(sf)## Linking to GEOS 3.13.0, GDAL 3.10.1, PROJ 9.5.1; sf_use_s2() is TRUElibrary(RColorBrewer)
library(ggplot2)
library(tidyterra)##
## Adjuntando el paquete: 'tidyterra'## The following object is masked from 'package:stats':
##
## filterAdd a new chunk by clicking the Insert Chunk button on the toolbar or by pressing Ctrl+Alt+I.
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(r <- rast(nrows=40, ncols=20, xmin=0, xmax=5, ymin=0, ymax=10))#crea raster vacio con columnas y filas.## class : SpatRaster
## size : 40, 20, 1 (nrow, ncol, nlyr)
## resolution : 0.25, 0.25 (x, y)
## extent : 0, 5, 0, 10 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84)The preview shows you a rendered HTML copy of the contents of the editor. Consequently, unlike Knit, Preview does not run any R code chunks. Instead, the output of the chunk when it was last run in the editor is displayed.
#values(r) <- runif(ncell(r)) distribucion cualquiera estadistica, de numeros aleatorios.
#values(r) <- seq(1,80,.1) organizacion orginal
#values(r) <- seq(80,1,-0.1) valores invertidos.
#values(r) <- seq(1,800,1)
values(r) <- seq(1,20,1)## Warning: [setValues] values were recycledtexto
plot(r)
text
q <- 100 * r^2text
plot(q)
text
q## class : SpatRaster
## size : 40, 20, 1 (nrow, ncol, nlyr)
## resolution : 0.25, 0.25 (x, y)
## extent : 0, 5, 0, 10 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84)
## source(s) : memory
## name : lyr.1
## min value : 100
## max value : 40000text
m <- q < 10 text
plot(m)
z <- sin(r)text
plot(z)
list.files()## [1] "~$Raster.docx" "AguaareaMeta.gpkg" "AguaMeta.gpkg"
## [4] "CiudadesMeta.gpkg" "ColombiaDatos.qgz" "Datos"
## [7] "poligono1.gpkg" "Raster.docx" "Raster.nb.html"
## [10] "Raster.Rmd" "Raster.tex" "Raster_files"
## [13] "ViasMeta.gpkg"text
elevacion <- rast("Datos/COL_msk_alt_tif/COL_msk_alt.tif")text
elevacion## class : SpatRaster
## size : 2136, 1800, 1 (nrow, ncol, nlyr)
## resolution : 0.008333333, 0.008333333 (x, y)
## extent : -81.8, -66.8, -4.3, 13.5 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84
## source : COL_msk_alt.tif
## name : COL_msk_alt
## min value : -28
## max value : 5453plot(elevacion)
cm <- crop(elevacion, vector, mask=TRUE)
meta <- st_read("Datos/munMeta.gpkg")## Reading layer `munMeta' from data source
## `C:\Users\usuagro\Documents\G2\G2\Datos\munMeta.gpkg' using driver `GPKG'
## Simple feature collection with 1 feature and 9 fields
## Geometry type: MULTIPOLYGON
## Dimension: XY
## Bounding box: xmin: -74.9206 ymin: 1.570401 xmax: -71.0749 ymax: 4.860201
## Geodetic CRS: WGS 84TERRA ENTIENDA GPKG
meta1 <- vect(meta)text
meta1## class : SpatVector
## geometry : polygons
## dimensions : 1, 9 (geometries, attributes)
## extent : -74.9206, -71.0749, 1.570401, 4.860201 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84 (EPSG:4326)
## names : ID_0 ISO NAME_0 ID_1 NAME_1 TYPE_1 ENGTYPE_1
## type : <num> <chr> <chr> <num> <chr> <chr> <chr>
## values : 53 COL Colombia 20 Meta Departamento Department
## NL_NAME_1 VARNAME_1
## <chr> <chr>
## NA NArecortar raster al departamento del meta
#elev_meta <- crop(elevacion, meta1, mask=TRUE)Organizaremos el sistema de coordenadas porque vector Geodetic CRS: WGS 84 y raster coord. ref. : lon/lat WGS 84 por lo realizamos con sf.
crs_meta1 <- crs(meta1) asignamos este crs a elevacion
crs(elevacion) <- crs_meta1verificamos que tengan el mismo crs.
crs(elevacion) == crs(meta1)## [1] TRUEext(meta1)## SpatExtent : -74.9206008911133, -71.0748977661133, 1.5704009532929, 4.86020088195812 (xmin, xmax, ymin, ymax)plot(meta1)
recortar raster al departamento del meta
elevacion2 <- crop(elevacion, ext(meta1), mask=TRUE)## Warning: [crop] mask=TRUE is ignored for SpatExtent objectsploteo
elevacion2## class : SpatRaster
## size : 395, 461, 1 (nrow, ncol, nlyr)
## resolution : 0.008333333, 0.008333333 (x, y)
## extent : -74.91667, -71.075, 1.566667, 4.858333 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84 (EPSG:4326)
## source(s) : memory
## varname : COL_msk_alt
## name : COL_msk_alt
## min value : 121
## max value : 4090plot(elevacion2)
Ponerle logica a las coordenadas porque teniamos las mismas coordenadsa
de colombia y presuntamente era el del meta.
sessionInfo()## R version 4.4.2 (2024-10-31 ucrt)
## Platform: x86_64-w64-mingw32/x64
## Running under: Windows 10 x64 (build 19045)
##
## Matrix products: default
##
##
## locale:
## [1] LC_COLLATE=Spanish_Colombia.utf8 LC_CTYPE=Spanish_Colombia.utf8
## [3] LC_MONETARY=Spanish_Colombia.utf8 LC_NUMERIC=C
## [5] LC_TIME=Spanish_Colombia.utf8
##
## time zone: America/Bogota
## tzcode source: internal
##
## attached base packages:
## [1] stats graphics grDevices utils datasets methods base
##
## other attached packages:
## [1] tidyterra_0.7.2 ggplot2_4.0.0 RColorBrewer_1.1-3 sf_1.0-21
## [5] rasterVis_0.51.7 lattice_0.22-6 terra_1.8-54
##
## loaded via a namespace (and not attached):
## [1] tidyr_1.3.1 generics_0.1.4 sass_0.4.10
## [4] class_7.3-22 KernSmooth_2.23-24 jpeg_0.1-11
## [7] digest_0.6.37 magrittr_2.0.3 evaluate_1.0.3
## [10] grid_4.4.2 fastmap_1.2.0 jsonlite_2.0.0
## [13] e1071_1.7-16 DBI_1.2.3 purrr_1.0.4
## [16] viridisLite_0.4.2 scales_1.4.0 codetools_0.2-20
## [19] jquerylib_0.1.4 cli_3.6.4 rlang_1.1.5
## [22] units_0.8-7 withr_3.0.2 cachem_1.1.0
## [25] yaml_2.3.10 tools_4.4.2 raster_3.6-32
## [28] parallel_4.4.2 deldir_2.0-4 dplyr_1.1.4
## [31] interp_1.1-6 vctrs_0.6.5 R6_2.6.1
## [34] png_0.1-8 zoo_1.8-14 proxy_0.4-27
## [37] lifecycle_1.0.4 classInt_0.4-11 pkgconfig_2.0.3
## [40] pillar_1.10.1 bslib_0.9.0 hexbin_1.28.5
## [43] gtable_0.3.6 glue_1.8.0 Rcpp_1.0.14
## [46] tidyselect_1.2.1 tibble_3.2.1 xfun_0.52
## [49] rstudioapi_0.17.1 knitr_1.50 latticeExtra_0.6-31
## [52] farver_2.1.2 htmltools_0.5.8.1 rmarkdown_2.29
## [55] compiler_4.4.2 S7_0.2.0 sp_2.2-0Cambiar color al raster.
map.pal(“elevation”, 10)
r <- rast(system.file(“ex/elev.tif”, package=“terra”)) plot(r, col=map.pal(“elevation”))
map.pal()
ggplot() +
geom_spatraster(data = elevacion2) +
scale_fill_whitebox_c(
palette = "muted",
labels = scales::label_number(suffix = "[m]"),
n.breaks = 12,
guide = guide_legend(reverse = TRUE)
) +
labs(
fill = "",
title = "elevación en Meta"
#subtitle = "Months of April, May and June"
)
vamos a guardar el archivo de elevacion del Meta
writeRaster(elevacion2, "Datos/ElevacionMeta.tif", overwrite=TRUE)(elevacionMeta <- rast("Datos/ElevacionMeta.tif"))## class : SpatRaster
## size : 395, 461, 1 (nrow, ncol, nlyr)
## resolution : 0.008333333, 0.008333333 (x, y)
## extent : -74.91667, -71.075, 1.566667, 4.858333 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84 (EPSG:4326)
## source : ElevacionMeta.tif
## name : COL_msk_alt
## min value : 121
## max value : 4090plot(elevacionMeta)