R Notebook3: Cálculo de la pendiente, aspecto de un DEM

rm(list=ls())

Primero vamos a llemar a la librería

library(raster)

## Loading required package: sp

dem <- raster(ncol=4, nrow=4, xmn=100, xmx=120, ymn=100, ymx=120)

ncell(dem)

## [1] 16

res(dem)

## [1] 5 5

valores <- c(50, 45, 50, 48, 30, 29, 30, 29, 10, 9, 9, 10, 25, 23, 19, 21)

(values(dem) <- valores)

##  [1] 50 45 50 48 30 29 30 29 10  9  9 10 25 23 19 21

plot(dem, main = "DEM")
text(dem)

crs(dem) <- CRS('+init=epsg:3115')

(slope = terrain(dem, 'slope', unit='degrees', neighbors=8))

## class      : RasterLayer 
## dimensions : 4, 4, 16  (nrow, ncol, ncell)
## resolution : 5, 5  (x, y)
## extent     : 100, 120, 100, 120  (xmin, xmax, ymin, ymax)
## crs        : +init=epsg:3115 +proj=tmerc +lat_0=4.596200416666666 +lon_0=-77.07750791666666 +k=1 +x_0=1000000 +y_0=1000000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs 
## source     : memory
## names      : slope 
## values     : 36.05503, 75.62313  (min, max)

plot(slope, main = "Pendiente")
text(slope)

(aspecto = terrain(dem, 'aspect', unit='degrees', neighbors=8))

## class      : RasterLayer 
## dimensions : 4, 4, 16  (nrow, ncol, ncell)
## resolution : 5, 5  (x, y)
## extent     : 100, 120, 100, 120  (xmin, xmax, ymin, ymax)
## crs        : +init=epsg:3115 +proj=tmerc +lat_0=4.596200416666666 +lon_0=-77.07750791666666 +k=1 +x_0=1000000 +y_0=1000000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs 
## source     : memory
## names      : aspect 
## values     : 164.0546, 181.4688  (min, max)

plot(aspecto, main = "Aspecto")
text(aspecto)