Agregar mi propia solución usando R
datos de precipitación aleatorios
library(tidyverse)
library(sp) # for coordinates, CRS, proj4string, etc
library(gstat)
library(maptools)
# Coordinates of gridded precipitation cells
precGridPts <- ("ID lat long
1 46.78125 -121.46875
2 46.84375 -121.53125
3 46.84375 -121.46875
4 46.84375 -121.40625
5 46.84375 -121.34375
6 46.90625 -121.53125
7 46.90625 -121.46875
8 46.90625 -121.40625
9 46.90625 -121.34375
10 46.90625 -121.28125
11 46.96875 -121.46875
12 46.96875 -121.40625
13 46.96875 -121.34375
14 46.96875 -121.28125
15 46.96875 -121.21875
16 46.96875 -121.15625
")
# Read precipitation cells
precGridPtsdf <- read.table(text = precGridPts, header = TRUE)
Convertir a un objeto sp
sp::coordinates(precGridPtsdf) <- ~long + lat # longitude first
Agregue un sistema de referencia espacial (SRS) o un sistema de referencia de coordenadas (CRS).
# CRS database: http://spatialreference.org/ref/epsg/
sp::proj4string(precGridPtsdf) <- sp::CRS("+proj=longlat +ellps=WGS84 +datum=WGS84")
str(precGridPtsdf)
#> Formal class 'SpatialPointsDataFrame' [package "sp"] with 5 slots
#> ..@ data :'data.frame': 16 obs. of 1 variable:
#> .. ..$ ID: int [1:16] 1 2 3 4 5 6 7 8 9 10 ...
#> ..@ coords.nrs : int [1:2] 3 2
#> ..@ coords : num [1:16, 1:2] -121 -122 -121 -121 -121 ...
#> .. ..- attr(*, "dimnames")=List of 2
#> .. .. ..$ : chr [1:16] "1" "2" "3" "4" ...
#> .. .. ..$ : chr [1:2] "long" "lat"
#> ..@ bbox : num [1:2, 1:2] -121.5 46.8 -121.2 47
#> .. ..- attr(*, "dimnames")=List of 2
#> .. .. ..$ : chr [1:2] "long" "lat"
#> .. .. ..$ : chr [1:2] "min" "max"
#> ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slot
#> .. .. ..@ projargs: chr "+proj=longlat +ellps=WGS84 +datum=WGS84 +towgs84=0,0,0"
Convertir a UTM 10N
utm10n <- "+proj=utm +zone=10 ellps=WGS84"
precGridPtsdf_UTM <- spTransform(precGridPtsdf, CRS(utm10n))
Datos hipotéticos de precipitación anual generados mediante la distribución de Poisson.
precDataTxt <- ("ID PRCP2016 PRCP2017 PRCP2018
1 2125 2099 2203
2 2075 2160 2119
3 2170 2153 2180
4 2130 2118 2153
5 2170 2083 2179
6 2109 2008 2107
7 2109 2189 2093
8 2058 2170 2067
9 2154 2119 2139
10 2056 2184 2120
11 2080 2123 2107
12 2110 2150 2175
13 2176 2105 2126
14 2088 2057 2199
15 2032 2029 2100
16 2133 2108 2006"
)
precData <- read_table2(precDataTxt, col_types = cols(ID = "i"))
Fusionar marco de datos Prec con archivo de forma Prec
precGridPtsdf <- merge(precGridPtsdf, precData, by.x = "ID", by.y = "ID")
precdf <- data.frame(precGridPtsdf)
Combinar el marco de datos de precipitación con el archivo de forma de precipitación (UTM)
precGridPtsdf_UTM <- merge(precGridPtsdf_UTM, precData, by.x = "ID", by.y = "ID")
# sample extent
region_extent <- structure(c(612566.169007975, 5185395.70942594, 639349.654465079,
5205871.0782451), .Dim = c(2L, 2L), .Dimnames = list(c("x", "y"
), c("min", "max")))
Defina la extensión de la interpolación espacial. Hazlo 4 km más grande en cada dirección
x.range <- c(region_extent[1] - 4000, region_extent[3] + 4000)
y.range <- c(region_extent[2] - 4000, region_extent[4] + 4000)
Cree la cuadrícula deseada a una resolución de 1 km
grd <- expand.grid(x = seq(from = x.range[1], to = x.range[2], by = 1000),
y = seq(from = y.range[1], to = y.range[2], by = 1000))
# Convert grid to spatial object
coordinates(grd) <- ~x + y
# Use the same projection as boundary_UTM
proj4string(grd) <- "+proj=utm +zone=10 ellps=WGS84 +ellps=WGS84"
gridded(grd) <- TRUE
Interpolar usando la distancia inversa ponderada (IDW)
idw <- idw(formula = PRCP2016 ~ 1, locations = precGridPtsdf_UTM, newdata = grd)
#> [inverse distance weighted interpolation]
# Clean up
idw.output = as.data.frame(idw)
names(idw.output)[1:3] <- c("Longitude", "Latitude", "Precipitation")
precdf_UTM <- data.frame(precGridPtsdf_UTM)
Trazar resultados de interpolación
idwPlt1 <- ggplot() +
geom_tile(data = idw.output, aes(x = Longitude, y = Latitude, fill = Precipitation)) +
geom_point(data = precdf_UTM, aes(x = long, y = lat, size = PRCP2016), shape = 21, colour = "red") +
viridis::scale_fill_viridis() +
scale_size_continuous(name = "") +
theme_bw() +
scale_x_continuous(expand = c(0, 0)) +
scale_y_continuous(expand = c(0, 0)) +
theme(axis.text.y = element_text(angle = 90)) +
theme(axis.title.y = element_text(margin = margin(t = 0, r = 10, b = 0, l = 0)))
idwPlt1
### Now looping through every year
list.idw <- colnames(precData)[-1] %>%
set_names() %>%
map(., ~ idw(as.formula(paste(.x, "~ 1")),
locations = precGridPtsdf_UTM, newdata = grd))
#> [inverse distance weighted interpolation]
#> [inverse distance weighted interpolation]
#> [inverse distance weighted interpolation]
idw.output.df = as.data.frame(list.idw) %>% as.tibble()
idw.output.df
#> # A tibble: 1,015 x 12
#> PRCP2016.x PRCP2016.y PRCP2016.var1.pred PRCP2016.var1.var PRCP2017.x
#> * <dbl> <dbl> <dbl> <dbl> <dbl>
#> 1 608566. 5181396. 2114. NA 608566.
#> 2 609566. 5181396. 2115. NA 609566.
#> 3 610566. 5181396. 2116. NA 610566.
#> 4 611566. 5181396. 2117. NA 611566.
#> 5 612566. 5181396. 2119. NA 612566.
#> 6 613566. 5181396. 2121. NA 613566.
#> 7 614566. 5181396. 2123. NA 614566.
#> 8 615566. 5181396. 2124. NA 615566.
#> 9 616566. 5181396. 2125. NA 616566.
#> 10 617566. 5181396. 2125. NA 617566.
#> # ... with 1,005 more rows, and 7 more variables: PRCP2017.y <dbl>,
#> # PRCP2017.var1.pred <dbl>, PRCP2017.var1.var <dbl>, PRCP2018.x <dbl>,
#> # PRCP2018.y <dbl>, PRCP2018.var1.pred <dbl>, PRCP2018.var1.var <dbl>