...
and adding, perhaps, to what David and Jeff told you:
Let ctr = c(ctr.lat, ctr.long) be the center of a bird colony (this
can be vectorized for many centers).
Then you need to figure out how much change in latitude and longitude
a distance of 500 meters is at that ctr (I think latitudes are e
This is mostly a domain-specific question about coordinate conversion and
algebra, not really about R. However, there are packages that could be useful
for this problem that are discussed in the CRAN "Analysis of Spatial Data" Task
View [1] and on the R-sig-geo mailing list [2].
Some points to
I'm no expert here but I have recently been playing with the package
'geosphere' it contains plenty of options to calculate distance
between two coordinates specified as lat and long.
install.packages('geosphere') # only needed once
library(geosphere)
coord1 <- c(43.60923,-79.322799)
coord2 <- c(
> On Jun 17, 2016, at 10:26 AM, Alice Domalik wrote:
>
> Hi List,
>
> I'm working with some bird tracking data, and to filter the data set, I need
> to exclude points taken at the colony.
> I would like to exclude coordinates from within a 500 meter radius of a point
> centered on the colon
This would be a good question for R-sig-geo.
To do it properly, there would be a few steps:
1. transform from lat/long (units=degrees) to projected coordinate system
(units = meters)
2. find one of the R functions for calculating distances (there are
several)
3. subset the data according to you
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