Calculo de Pendiente y orientación

Paula Juliana Virguez Gomez

30 de marzo de 2020

rm(list = ls())

library(raster)

dem <- raster(ncol=3, nrow=3, xmn=100, xmx=115, ymn=100, ymx=115)

Cuántas celdas compone el DEM

ncell(dem)

[1] 9

Resolución espacial o tamaño de celda

res(dem)

[1] 5 5

Asignar valores de elevación a los DEM:

valores <- c(50, 45, 50, 30, 30, 30, 8, 10, 10)

(values(dem) <- valores)

[1] 50 45 50 30 30 30  8 10 10

Visualizar los DEM a lo largo de los valores de elevación:

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

Asignar un sistema de referencia de coordenadas a los DEM:

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

Calculo de la pendiente y orientación

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

class      : RasterLayer 
dimensions : 3, 3, 9  (nrow, ncol, ncell)
resolution : 5, 5  (x, y)
extent     : 100, 115, 100, 115  (xmin, xmax, ymin, ymax)
crs        : +init=epsg:3115 
source     : memory
names      : slope 
values     : 75.25766, 75.25766  (min, max)

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

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

class      : RasterLayer 
dimensions : 3, 3, 9  (nrow, ncol, ncell)
resolution : 5, 5  (x, y)
extent     : 100, 115, 100, 115  (xmin, xmax, ymin, ymax)
crs        : +init=epsg:3115 
source     : memory
names      : aspect 
values     : 180.7538, 180.7538  (min, max)

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

TAREA

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

ncell(dem_tarea)

[1] 16

res(dem_tarea)

[1] 5 5

valores_tarea <- c (50,45,50,48,30,29,30,29,10,9,9,10,26,23,19,21)

(values(dem_tarea) <- valores_tarea)

 [1] 50 45 50 48 30 29 30 29 10  9  9 10 26 23 19 21

plot(dem_tarea, main= "DEM2")
text(dem_tarea)

MAGNA-SIRGAS / Colombia Far West zone

crs(dem_tarea) <- CRS('+init=epsg:3114')

Pendiente

(slope = terrain(dem_tarea, '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:3114 
source     : memory
names      : slope 
values     : 35.43233, 75.62313  (min, max)

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

Aspecto

(aspecto2= terrain(dem_tarea, '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:3114 
source     : memory
names      : aspect 
values     : 161.5651, 181.4688  (min, max)

plot(aspecto2,main="Aspecto")
text(aspecto2)