# Exploring vector data and raster data.
# Load packages
library(sp)
library(maptools) # spatial vector data
## Checking rgeos availability: TRUE
library (rgdal) # Geospatial Data Abstraction Library for spatial data
## rgdal: version: 1.4-8, (SVN revision 845)
## Geospatial Data Abstraction Library extensions to R successfully loaded
## Loaded GDAL runtime: GDAL 2.2.3, released 2017/11/20
## Path to GDAL shared files: C:/Users/Usuario/Documents/R/win-library/3.6/rgdal/gdal
## GDAL binary built with GEOS: TRUE
## Loaded PROJ.4 runtime: Rel. 4.9.3, 15 August 2016, [PJ_VERSION: 493]
## Path to PROJ.4 shared files: C:/Users/Usuario/Documents/R/win-library/3.6/rgdal/proj
## Linking to sp version: 1.4-1
library (raster) # raster and vector data read & write
# Exploring vector data.
setwd("E:/Clases R/Huancavelica/datos shape")
list.files(path=".")
## [1] "25m" "26m" "cuencamantaro.dbf"
## [4] "cuencamantaro.prj" "cuencamantaro.shp" "cuencamantaro.shx"
## [7] "Datosgeoquimica.dbf" "Datosgeoquimica.prj" "Datosgeoquimica.shp"
## [10] "Datosgeoquimica.shx" "Departamento.dbf" "Departamento.prj"
## [13] "Departamento.shp" "Departamento.shx" "Distrito.dbf"
## [16] "Distrito.prj" "Distrito.shp" "Distrito.shx"
## [19] "EI.dbf" "EI.prj" "EI.shp"
## [22] "EI.shx" "municipio.dbf" "municipio.mshp"
## [25] "municipio.prj" "municipio.shp" "municipio.shx"
## [28] "Provi.dbf" "Provi.prj" "Provi.shp"
## [31] "Provi.shx" "Puntosedu.dbf" "Puntosedu.prj"
## [34] "Puntosedu.shp" "Puntosedu.shx"
point <- readOGR('Puntosedu.shp', layer='Puntosedu')
## OGR data source with driver: ESRI Shapefile
## Source: "E:\Clases R\Huancavelica\datos shape\Puntosedu.shp", layer: "Puntosedu"
## with 766 features
## It has 10 fields
summary(point)
## Object of class SpatialPointsDataFrame
## Coordinates:
## min max
## coords.x1 442084 533835
## coords.x2 8549115 8631410
## Is projected: TRUE
## proj4string :
## [+proj=utm +zone=18 +south +ellps=WGS84 +units=m +no_defs]
## Number of points: 766
## Data attributes:
## COD_MOD CODLOCAL DIR_CEN
## Min. : 1506 Min. : 1506 PLAZA PRINCIPAL S/N :211
## 1st Qu.: 430597 1st Qu.: 173228 PLAZA PRINCIPAL :174
## Median :1059612 Median : 175620 PARQUE PLAZA PRINCIPAL S/N: 10
## Mean :1315143 Mean : 837476 CALLE REAL S/N : 7
## 3rd Qu.:1602893 3rd Qu.: 678999 AVENIDA HUANCAVELICA S/N : 6
## Max. :3895115 Max. :3895115 JIRON HILDAURO CASTRO S/N : 6
## (Other) :352
## CODGEO CODCP_MED CEN_POB N_ALUM
## Min. : 90101 Min. :110077 HUANCAVELICA : 41 Min. : 0.00
## 1st Qu.: 90103 1st Qu.:121198 ASCENSION : 15 1st Qu.: 6.00
## Median : 90106 Median :132420 SANTA ANA : 14 Median : 15.00
## Mean : 90507 Mean :308632 VISTA ALEGRE : 10 Mean : 49.86
## 3rd Qu.: 90117 3rd Qu.:540870 YANANACO : 8 3rd Qu.: 47.75
## Max. :151032 Max. :683253 SAN CRISTOBAL: 7 Max. :1413.00
## (Other) :671
## N_DOCENTES X Y
## Min. : 0.000 Min. :442084 Min. :8549115
## 1st Qu.: 1.000 1st Qu.:497277 1st Qu.:8587191
## Median : 1.500 Median :505086 Median :8601020
## Mean : 3.786 Mean :504276 Mean :8599779
## 3rd Qu.: 4.000 3rd Qu.:515095 3rd Qu.:8610324
## Max. :85.000 Max. :533835 Max. :8631410
##
# Attribute analysis
sd(point$N_ALUM) #calculation of standard deviation of a column
## [1] 120.0881
mean(point$N_ALUM) #calculation of the average data set
## [1] 49.86423
length(point$N_ALUM) # amount of data in sample
## [1] 766
summary(point$N_ALUM) #calculation of descriptive statistics.
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.00 6.00 15.00 49.86 47.75 1413.00
# Spatial exploration
point #full exploration
## class : SpatialPointsDataFrame
## features : 766
## extent : 442084, 533835, 8549115, 8631410 (xmin, xmax, ymin, ymax)
## crs : +proj=utm +zone=18 +south +ellps=WGS84 +units=m +no_defs
## variables : 10
## names : COD_MOD, CODLOCAL, DIR_CEN, CODGEO, CODCP_MED, CEN_POB, N_ALUM, N_DOCENTES, X, Y
## min values : 1506, 1506, ACCOCCASA, 90101, 110077, 3 DE MAYO, 0, 0, 442084, 8549115
## max values : 3895115, 3895115, ZUNIPAMPA, 151032, 683253, ZUNIPAMPA, 1413, 85, 533835, 8631410
class(point) # What type of vector is a point, line or polygon.
## [1] "SpatialPointsDataFrame"
## attr(,"package")
## [1] "sp"
extent(point) # Extreme values
## class : Extent
## xmin : 442084
## xmax : 533835
## ymin : 8549115
## ymax : 8631410
crs(point) # reference system
## CRS arguments:
## +proj=utm +zone=18 +south +ellps=WGS84 +units=m +no_defs
names(point) # Attribute name.
## [1] "COD_MOD" "CODLOCAL" "DIR_CEN" "CODGEO" "CODCP_MED"
## [6] "CEN_POB" "N_ALUM" "N_DOCENTES" "X" "Y"
# Map point shape file
x11()
plot(point,
main= "Number of schools Huancavelica",
pch=10, # symbol type
cex=0.8, # symbol size
axes=TRUE) # symbol size
hist(point$N_DOCENTES,
main= "Number of teachers by school Huancavelica")
# Exploring raster data.
setwd("E:/Datos dem/Colombia/Datos Alos palsar")
files <- list.files(pattern='.tif')
files
## [1] "AP_20846_FBS_F0120_RT2.dem.tif"
dem <- raster("E:/Datos dem/Colombia/Datos Alos palsar/AP_20846_FBS_F0120_RT2.dem.tif")
dem
## class : RasterLayer
## dimensions : 553, 485, 268205 (nrow, ncol, ncell)
## resolution : 30, 30 (x, y)
## extent : 1097115, 1111665, 1269285, 1285875 (xmin, xmax, ymin, ymax)
## crs : +proj=tmerc +lat_0=4.596200416666666 +lon_0=-74.07750791666666 +k=1 +x_0=1000000 +y_0=1000000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
## source : E:/Datos dem/Colombia/Datos Alos palsar/AP_20846_FBS_F0120_RT2.dem.tif
## names : AP_20846_FBS_F0120_RT2.dem
## values : 603.6502, 1775.037 (min, max)
summary(dem)
## Warning in .local(object, ...): summary is an estimate based on a sample of 1e+05 cells (37.28% of all cells)
## AP_20846_FBS_F0120_RT2.dem
## Min. 600.0993
## 1st Qu. 810.8240
## Median 931.4439
## 3rd Qu. 1082.3910
## Max. 1784.5298
## NA's 0.0000
hist(dem,
main="Frecuency data",
xlab="altitude elevation",
border="blue",
col="green",
xlim=c(500,2000),
las=1,
breaks=5)
## Warning in .hist1(x, maxpixels = maxpixels, main = main, plot = plot, ...): 37%
## of the raster cells were used. 100000 values used.
x11()
plot(dem, main= "DEM Alos Palsar ")
