urban_context: Urban context

In ricardoochoa/urban.context: Urban context

Description

For a selected point in x-y (decilmal long-lat) coordinates, subset and summarise points found in an specified radius.

Usage

urban_context(x, y, data, df.x = "x", df.y = "y", variable = "variable", radius = 1, FUN, empty.value = 0)

Arguments

x	Longitude coordinates in decimal degrees for the reference point.
y	Latitude coordinates in decimal degrees for the reference point.
data	data.frame with the observations that will be sumarised. This data.frame should have at least three columns: x, y, and variable.
df.x	Name of the column in the dataframe which includes the longitude coordinates in decimal degrees for each observation.
df.y	Name of the column in the dataframe which includes the latitude coordinates in decimal degrees for each observation.
variable	Name of the column in the dataframe "data", which includes the values to be summarised.
radius	Search radius in kilometers of the circunference with center in x, y. Default is set to 1 km.
FUN	Function to be applied.
empty.value	What to return if no point are found. Default is set to 0.

Value

A numeric value: the result of applying the function "FUN" to the column "variable", from a subset of "data". The subset includes all observations where the distance between (x, y) and (df.x, df.y) is less or equal than the distance defined by "radius".

Author(s)

Ricardo Ochoa Sosa

Examples

my.data <-
read.table(header = TRUE, text = "
x	y	variable
-99.495	19.16	1
-99.490	19.16	5
-99.500	19.14	2
-99.490	19.15	10
")

urban_context(x = -99.490,
              y = 19.16,
              data = my.data,
              FUN = mean)

ricardoochoa/urban.context documentation built on May 27, 2019, 7:41 a.m.