From afa37e4667ace42c1f43b01b613e639772cfeb75 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Sat, 11 Jul 2015 19:13:37 -0700 Subject: [PATCH] altoslib: Convert longitude from distance in AltosMapTransform This computes the longitude cooresponding to a specific distance at a specific latitude. Signed-off-by: Keith Packard --- altoslib/AltosMapTransform.java | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/altoslib/AltosMapTransform.java b/altoslib/AltosMapTransform.java index 11ed4eb9..7615c83b 100644 --- a/altoslib/AltosMapTransform.java +++ b/altoslib/AltosMapTransform.java @@ -117,4 +117,12 @@ public class AltosMapTransform { offset_x = centre_pt.x - width / 2.0; offset_y = centre_pt.y - height / 2.0; } + + public static double lon_from_distance(double lat, double distance) { + double c = AltosGreatCircle.earth_radius * Math.cos(lat * Math.PI / 180) * 2 * Math.PI; + + if (c < 10) + return 0; + return distance/c * 360.0; + } } -- 2.30.2