In WP7, is it possible to show compass direction based on the given latitude and longitude values. (For example, if I am in India and if the latitude and longitude values of a place in some other country is given). If yes, please give some idea on how to achieve this.
This is what is known as the Second (inverse) geodetic problem.
"Given two points, determine the azimuth and length of the line
(straight line, arc or geodesic) that connects them." Wikipedia
You can get the distance using System.Device.Location.GeoCoordinate.GetDistanceTo(). Otherwise have a look at the excellent C# Geodesy Library for GPS – Vincenty’s Formulae. In particular the GeodeticCurve.
Related
My app currently uses Location Services. During debugging, I retrieve my current location using GetLastKnownLocationAsync: myposition.Latitude is 40.758896 while myposition.Latitude is -73.985130.
My SQL Database has a list of Walmart stores, and there's a Walmart with Latitude & Longitude of 40.660992 & -73.7267629.
How can I calculate the driving distance between my set of coordinates and Walmart's coordinates? It would be something like Google Maps' Driving Directions or Waze.
I understand that I can use this SO link to calculate the distance between two sets of point, but I assume apps like Google Maps or Waze consider the actual driving distance between two sets of points. The link above would be great if there were a straight street between two points. Obviously, that's not the case.
I have used Xamarin.Essential library to find the distance between two point
You can use something like this
var location = new Location(21.705723, 72.998199);
var otherLocation = new Location(22.3142, 73.1752);
double distance = location.CalculateDistance(otherLocation,DistanceUnits.Kilometers);
I'm trying to match a latitude and longitude pair to a road segment that has a start and end latitude and longitude. All of the formulas I've been able to find query by the closest match to a single latitude and longitude, but not to a pair. I suppose one option is to get the average, or center of the segment, but this is not ideal. I'm querying this in SQLLite since my data is in GeoPackage format, but if anyone even has a formula to use I can translate that to SQLLite.
Thanks!
Hmm interesting. Conceptually, and without considering performance, would the following work? (consider this untested pseudo):
SELECT
MIN(ABS(lon_field - :lon1)) AS start_lon,
MIN(ABS(lat_field - :lat1)) AS start_lat,
MIN(ABS(lon_field - :lon2)) as end_lon,
MIN(ABS(lat_field - :lat2)) AS end_lat;
In my app I am getting the latitude , longitude co-ordinates of places using GeocodeService now I want to get distance between these places.
I've tried GetDistanceTo method to get the distance two location co-ordinates but it gives me stright distance.
How can I calculate driving distance between two locations?
thanks in advance
To calculate the driving distance you'll have to use the Bing Routes API (or Google, but I assume you're using Bing Maps).
There's an example of using the api to find a driving route between two places here: http://msdn.microsoft.com/en-us/library/gg636957.aspx
The general call is:
http://dev.virtualearth.net/REST/V1/Routes/Driving?o=xml&wp.0=location1&wp.1=location2&avoid=minimizeTolls&key=BingMapsKey
You'll have to register for a Bing Maps API key, and then replace location1 and location2 with the locations you like.
The distance should be returned in travelDistance in the json or xml
I have a dxf file of a town in meter coordinates. I need to extract polylines from the map and convert them to geographical coordinates. My idea is to add 3 or 4 points on the map with known coordinates. I will place them using google map as reference. These 3 or 4 points will be placed at intersections roads so I can not place them as they defined a rectangle (I think it would be simpler).
I can not found out what calculation I have to do to convert all the coordinates of the objects of the map.
google map earth radius: 6378137 meter.
so, If I consider 3 points, I will have 3 relations:
(x1,y1) with (lat1, lng1)
(x2,y2) with (lat2, lng2)
(x3,y3) with (lat3, lng3)
I have done one simple conversion with only 2 points but I'd like a more accurate result.
I preferably use c/c++ to do it.
example of one equivalent point:
latitude: -2.148707
longitude: -79.876270
x: 2012078.15
y: 498355.88
It's not a UTM, I verify it from here. Because I do not know if it s a normalized.
I googled a lot, I found libraries, but without knowing if tmy coordinates meet a specific format, I don't think I can use one.
Anyway, thanks to read and I hope someone could help me.
It is not as easy at that. First you need to know which reference ellipsoid you are using (e.g. WGS-84) and then which projection. I wouldn't try to implement this by hand, but use postgis instead, which would do all this ugly work for you.
The correct way is to ask the provider of the file what the coordinate system is related to. dxf is not realy a suitable format. you need a format like ESRI Shp file or mif/mid with a defined geographic coordinate system.
otherwise it is a bit unclear if the data are precise enough, to be used for geographic reference.
However it is not difficult to transform between meters and wgs84 lat longitude, especially if the area is not more than 10-20 miles.
you could use as first try the cylyndrical equidistant transformation, which is only a few lines of simple code. look also if the y-achsis in the dxf file points to the nort pole, otherwise you must find out that amount of false northing and rotate back to north.
MapInfo Professional is a tool with free evaluation period, this tool alows to specify reference points for such unknown coordinate systems. (at least for bitmaps i rememer that feature).
But if you are a professional sw developper, You should reject that file and demand a version in wgs84 lat lon.
I currently have a robot with some sensors, like a GPS, an accelerometer and a compass. The thing I would like to do is my robot to reach a GPS coordinate that I enter. I wondered if any algorithm to do that already existed. I don't want a source code, which wouldn't have any point, just the procedure to follow for my robot to do so, for me to be able to understand what I do... At the moment, let's imagine that I can access the GPS coordinate everytime, so no need of a Kalman filter. I know it's unrealistic, but I would like to programm it step by step, and Kalman is the next step.
If anyone has an idea...
To get a bearing (positive angle east of north) between two lat-long points use:
bearing=mod(atan2(sin(lon2-lon1)*cos(lat2),(lat1)*sin(lat2)-sin(lat1)*cos(lat2)*cos(lon2-lon1)),2*pi)
Note - angles probably have to be in radians depending on your math package.
But for small distances you can just calculate how many meters in one degree of lat and long at your position and then treat them as flat X,Y coords.
For typical 45deg latitudes it's around 111.132 km/deg lat, 78.847 km/deg lon.
1) orient your robot toward its destination.
2) Move forward until the distance between you and your destination is increasing where you should go back to 1)
3) BUT ... if you are close enough (under a threshold), consider that you arrived at the destination.
You can use the Location class. It's BearingTo function computes the bearing you have to follow to reach another location.
There is a very nice page explaining the formulas between GPS-based distance, bearing, etc. calculation, which I have been using:
http://www.movable-type.co.uk/scripts/latlong.html
I am currently trying to do these calculations myself, and just found out that in Martin Becket answer there is an error. If you compare to the info of that webpage, you will see that the part in the middle:
(lat1)*sin(lat2)
should actually be:
cos(lat1)*sin(lat2)
Would have left a comment, but don't have the reputation yet...