Distance accuracy depends on the map projection used. All map projections involve distorsions as portions of a spheroid are transfered to a plane. Geodist latitude0 longitude0 latitude longitude, gen(km_to_wellNo)īysort wellNo0 (km_to_wellNo): egen hasNearby = total(km_to_wellNo > 0 & km_to_wellNo < 1)Įrase "temp.dta"If the locations are in map coordinates (in meters, kms, yards, etc.) instead of geographic coordinates, then you can only compute distances on the map (using Euclidean distances). If you are a registered author of this item, you may also want to check the citations tab in your RePEc Author. * second method - form all pairwise combinations of points Neighbor(wellNo latitude longitude) within(1) longīysort wellNo0 (km_to_wellNo): keep if _n = _N Geonear wellNo0 latitude longitude using "temp.dta", /// If the value is expressed in degrees, it must be between 90 and 90.
Note that in many cases,geonear city1 latitude1 longitude1 using 'distance. Now, we only need to use an option of within () with the geonear command. Coordinates that are located north of the equator have positive values coordinates that are located south of the equator have negative values. The Stata-to-Python translations below are written assuming that you have a single DataFrame called df. Previously, with the geodist command, we had to follow several steps to obtain the cities that were within a 30km radius of the base cities.
Input float wellNo double(longitude latitude) is a numeric constant, variable, or expression that specifies the coordinate of a given position north or south of the equator. Input float wellNo str24(longitude latitude)ĮndThis will create a variable = 1 if there exists another well within 1 km of it.
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