I want to sum the values of each polygon, indicated as cod_area.
library(sf)
sf.data <- structure(list(cod_area = c(34275L, 34275L, 34347L, 34347L),
cod_reg = c(1664464L, 1664467L, 1665398L, 1665400L), val = c(2562.5,
2166.66666666667, 10288.75, 3613), geometry = structure(list(
structure(list(structure(c(-46.5, -46.3333333, -46.3333333,
-46.5, -46.5, -24.3333333, -24.3333333, -24.5, -24.5,
-24.3333333), dim = c(5L, 2L))), class = c("XY", "POLYGON",
"sfg")), structure(list(structure(c(-46.5, -46.3333333,
-46.3333333, -46.5, -46.5, -24.3333333, -24.3333333,
-24.5, -24.5, -24.3333333), dim = c(5L, 2L))), class = c("XY",
"POLYGON", "sfg")), structure(list(structure(c(-46.6666667,
-46.5, -46.5, -46.6666667, -46.6666667, -24.3333333,
-24.3333333, -24.5, -24.5, -24.3333333), dim = c(5L,
2L))), class = c("XY", "POLYGON", "sfg")), structure(list(
structure(c(-46.6666667, -46.5, -46.5, -46.6666667,
-46.6666667, -24.3333333, -24.3333333, -24.5, -24.5,
-24.3333333), dim = c(5L, 2L))), class = c("XY",
"POLYGON", "sfg"))), n_empty = 0L, class = c("sfc_POLYGON",
"sfc"), precision = 0, bbox = structure(c(xmin = -46.6666667,
ymin = -24.5, xmax = -46.3333333, ymax = -24.3333333), class = "bbox"), crs = structure(list(
input = "EPSG:4674", wkt = "GEOGCRS[\"SIRGAS 2000\",\n DATUM[\"Sistema de Referencia Geocentrico para las AmericaS 2000\",\n ELLIPSOID[\"GRS 1980\",6378137,298.257222101,\n LENGTHUNIT[\"metre\",1]]],\n PRIMEM[\"Greenwich\",0,\n ANGLEUNIT[\"degree\",0.0174532925199433]],\n CS[ellipsoidal,2],\n AXIS[\"geodetic latitude (Lat)\",north,\n ORDER[1],\n ANGLEUNIT[\"degree\",0.0174532925199433]],\n AXIS[\"geodetic longitude (Lon)\",east,\n ORDER[2],\n ANGLEUNIT[\"degree\",0.0174532925199433]],\n USAGE[\n SCOPE[\"Horizontal component of 3D system.\"],\n AREA[\"Latin America - Central America and South America - onshore and offshore. Brazil - onshore and offshore.\"],\n BBOX[-59.87,-122.19,32.72,-25.28]],\n ID[\"EPSG\",4674]]"), class = "crs"))), row.names = c(NA,
4L), class = c("sf", "data.frame"), sf_column = "geometry", agr = structure(c(cod_area = NA_integer_,
cod_reg = NA_integer_, val = NA_integer_), class = "factor", levels = c("constant",
"aggregate", "identity")))
class(sf.data)
[1] "sf" "data.frame"
I expected to have two values, 4729.167 for cod_area 34275 and 13901.75 for cod_area 34347. But ...
aggregate(val~geometry,data=sf.data,FUN=sum)
Error in model.frame.default(formula = val ~ geometry, data = sf.data) :
invalid type (list) for variable 'geometry'
aggregate(sf.data["val"],by=list(sf.data$geometry),FUN=sum)
Error in order(y) : unimplemented type 'list' in 'orderVector1'
among other attempts. I somehow solved the problem with
agg.val <- aggregate(val~cod_area,sf.data,FUN=sum)
merge(agg.val,unique(sf.data[,1]),by="cod_area")
Is there a more direct way to do the calculation (without using dplyr)?
You can set the do_union parameter to TRUE (but it doesn't seem to work with the formula method):
aggregate(sf.data, list(cod_area = sf.data$cod_area), FUN=sum, do_union = TRUE)
Simple feature collection with 2 features and 4 fields
Attribute-geometry relationships: aggregate (3), identity (1)
Geometry type: POLYGON
Dimension: XY
Bounding box: xmin: -46.66667 ymin: -24.5 xmax: -46.33333 ymax: -24.33333
Geodetic CRS: SIRGAS 2000
cod_area cod_area.1 cod_reg val geometry
1 34275 68550 3328931 4729.167 POLYGON ((-46.33333 -24.333...
2 34347 68694 3330798 13901.750 POLYGON ((-46.5 -24.33333, ...