Here’s what worked for me, without so much bs. int x = (int) ((MAP_WIDTH/360.0) * (180 + lon)); int y = (int) ((MAP_HEIGHT/180.0) * (90 – lat)); The lat,lon coordinates were given to me by Android devices. So they should be in the same standard used by all Google Earth/Map products.
GPS, the Global Positioning System run by the United States Military, is free for civilian use, though the reality is that we’re paying for it with tax dollars. However, GPS on cell phones is a bit more murky. In general, it won’t cost you anything to turn on the GPS in your cell phone, but … Read more
Here’s a simple example: GeoCoordinateWatcher watcher; watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.Default) { MovementThreshold = 20 }; watcher.PositionChanged += this.watcher_PositionChanged; watcher.StatusChanged += this.watcher_StatusChanged; watcher.Start(); private void watcher_StatusChanged(object sender, GeoPositionStatusChangedEventArgs e) { switch (e.Status) { case GeoPositionStatus.Disabled: // location is unsupported on this device break; case GeoPositionStatus.NoData: // data unavailable break; } } private void watcher_PositionChanged(object sender, GeoPositionChangedEventArgs<GeoCoordinate> … Read more
No exact solution exists There is no isometric map from the sphere to the plane. When you convert lat/lon coordinates from the sphere to x/y coordinates in the plane, you cannot hope that all lengths will be preserved by this operation. You have to accept some kind of deformation. Many different map projections do exist, … Read more
You are correct, there is no universal standard on the order: In mathematical functions which do an universal conversion, between x,y or lon,lat or inverse, the lon,lat order should be used, because the x-axis relates to longitude and y to latitude and the x,y order is usually preferred. Further, if you program a piece of … Read more
Here’s a simple Kalman filter that could be used for exactly this situation. It came from some work I did on Android devices. General Kalman filter theory is all about estimates for vectors, with the accuracy of the estimates represented by covariance matrices. However, for estimating location on Android devices the general theory reduces to … Read more