Add distance to a latitude or longitude

Question

Say I have a latitude of 38.802610 and a longitude of -116.419389 and I want to be able to add a distance to that, 20 miles for example.

So far I have came up with a rough idea on how I would do this:

• Firstly, work out how many miles are in 1° of latitude, say for example it was 30
• Then, divide one by it:
  • 1 / 30 = 0.033333
• Add it to my original latitude to get my maximum ° of latitude:
  • 38.802610 + 0.033333 = 38.8355943
• Subtract it to my original latitude to get my minimum ° of latitude:
  • 38.802610 - 0.033333 = 38.769277

But this is flawed because there seems to be no direct conversion for longitude as from what I've read the calculation varies. I have looked around and found some resources but I can't find one that applies directly to my question. I came across Haversine Formula but I can't find a way of applying it to my situation as, from what I've read, it's used for calculating the distance between two points.

Ultimately, I need to be able to find out the:

• maximum latitude (my current latitude + given distance e.g 20 miles)

• minimum latitude (my current latitude - given distance e.g 20 miles)

• maximum longitude (my current longitude + given distance e.g 20 miles)

• minimum longitude (my current longitude - given distance e.g 20 miles)

Answer 1

if interested in a python suggestion - using OGR

from osgeo import ogr, osr

# setup function to reproject coordinates
def convertCoords(xy, src='', targ=''):

    srcproj = osr.SpatialReference()
    srcproj.ImportFromEPSG(src)
    targproj = osr.SpatialReference()
    if isinstance(targ, str):
        targproj.ImportFromProj4(targ)
    else:
        targproj.ImportFromEPSG(targ)
    transform = osr.CoordinateTransformation(srcproj, targproj)

    pt = ogr.Geometry(ogr.wkbPoint)
    pt.AddPoint(xy[0], xy[1])
    pt.Transform(transform)

    return([pt.GetX(), pt.GetY()])

you can then feed the lat/long coordinates to the function, with appropriate epsg codes (for this example, we'll use WGS84 as the input and albers for the output):

coords =  (-116.419389, 38.802610)
albersXY = convertCoords(coords, 4326, 5070)

add 20 miles to one direction of the albers coordinates (which are in meters)

albersXY[0] = albersXY[0] + 20 * 1609.344
# albersXY[1] = albersXY[1] + 20 * 1609.344

then convert from albers back to WGS

newlonlat = convertCoords(albersXY, 5070, 4326)
print(newlonlat)
>>> [-116.13229978439009, 39.14407586190597]