Given
- Line defined by two coordinates (latitude / longitude in decimal degrees)
AandB - Offset / distance to the line in meters
d
Wanted
- Coordinates
A1,A2,B1,B2("below" and "above") perpendicular to the line at a distancedfor pointAandB
What I have tried already
In a cartesian coordinate system, the calculation can be done easily, e.g. following How do you find a point at a given perpendicular distance from a line? given x1, x2, y1, y2 and N being the distance:
dx = x1-x2
dy = y1-y2
dist = sqrt(dx*dx + dy*dy)
dx /= dist
dy /= dist
x3 = x1 + (N/2)*dy
y3 = y1 - (N/2)*dx
x4 = x1 - (N/2)*dy
y4 = y1 + (N/2)*dx
What I have achieved
I have tried the above solution on pen & paper with coordinates like A (5/3) and B (10/4), the results were fine, the calculated points were on a perpendicular line.
Then, I have tried it with "real coordinates" (e.g. lat=52.50004577636719, lon=13.39927864074707) and I treated those coordinates as if they were normal 2D cartesian coordinates. The output is distorted -> the points are not on the perpendicular line.
Questions
When I assume that my coordinates are "cartesian" coordinates, then I get distorted results, e.g. when rendering those coordinates it appears to be not really perpendicular. Can I somehow get rid of this distortion?
Is "perpendicular to a line between two coordinates" defined at all when dealing with latitude / longitude values?
Is there a way to use the "cartesian method" and then map back to real latitude / longitude?
[EDIT] Solved by calculating the bearing:
https://stackoverflow.com/a/60550894/844416 https://www.movable-type.co.uk/scripts/latlong.html https://www.igismap.com/formula-to-find-bearing-or-heading-angle-between-two-points-latitude-longitude/
