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Questions tagged [wgs84]

WGS 84 is the reference coordinate system used by the Global Positioning System

  1. The coordinate origin of WGS 84 is meant to be located at the Earth's center of mass; the error is believed to be less than 2 cm.
  2. The WGS 84 meridian of zero longitude is the IERS Reference Meridian, 5.31 arc seconds or 102.5 metres east of the Greenwich meridian at the latitude of the Royal Observatory.
  3. The WGS 84 datum surface is an oblate spheroid (ellipsoid) with major (equatorial) radius a = 6378137 m at the equator and flattening f = 1/298.257223563. The polar semi-minor axis b is 6356752.3142 m.

References

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GeoJSON and MongoDB: Is it worth it to store points as GeoJSON.Point?

With the introduction of 2.3 > MongoDB has become even more useful with location data handling and querying. MongoDB stores documents as BSON, so each document with have all the document fields, which obviously potentially leads to larger databases…
nevi_me
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Java code for WGS84 to Google map position and back

Searching for some sample code for converting a point in WGS84 coordinate system to a map position in Google Maps (pixel position), also supporting zoom levels. If the codes is well commented, then it can also be in some other language. You can…
JaanusSiim
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How to transform coordinate from WGS84 to a coordinate in a projection with PROJ.4?

I have a GPS-coordinate in WGS84 that I would like to transform to a map-projection coordinate in SWEREF99 TM using PROJ.4 in Java or Proj4js in JavaScript. Its hard to find documentation for PROJ.4 and how to use it. If you have a good link, please…
Jonas
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Convert X,Y pixel to Longitude and Latitude

I have an image 8640x11520 pixels from a part of the map in real scale. I need convert my x, y point to coordinate, anyone has an idea to find out it?? var mapWidth = 8640; var mapHeight = 11520; var mapLatitudeStart = 28.349768989955244; var…
André Gonçalves
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How does getAltitude() of Android GPS Location Works

HI I tried to implement a simple GPS tracker. Therefore is used lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this); Then i used the public void…
RoflcoptrException
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WGS84 Geoid Height Altitude Offset for external GPS data on IOS

For an application I'm writing we are interfacing IOS devices with an external sensor which outputs GPS data over a local wifi network. This data comes across in a "raw" format with respect to altitude. In general all GPS altitude needs to have a…
Jeef
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Distance using WGS84-ellipsoid

Consider points P1 (60°N, 20°E, 0) and P2 (60°N, 22°E, 0) on the surface of the Earth What is the shortest distance between the points P1 and P2, when the shape of the Earth is modeled using WGS-84 ellipsoid?
Daniele Peruzzini
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If You Have A GeoTiff, Would It Be Possible To Transform A Lat/Lon Point To An X,Y Using The GeoTransform?

I'm using the GDAL library. Currently, I can take in an upper left point and an upper right point and chip an image out of the original. What I'd like to do now, is take in two WKT points and convert to X,Y coordinatees to do the same thing. I…
avtoader
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Why is boost::geometry geographic Vincenty distance inaccurate around the Equator?

I require a function to calculate the distance between a pair of WGS 84 positions to a high degree of accuracy and I was planning to use the geographic functions from boost geometry. The boost geometry Design Rational states: There is the Andoyer…
kenba
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Converting LLA to XYZ

Can you help me to convert lla to xyz coordnates. I am using earthRadius = 6378.137; var x = earthRadius * Math.cos(lat)*Math.cos(lon); var y = earthRadius * Math.cos(lat)*Math.sin(lon); var z = earthRadius * Math.sin(lat); this method to convert…
mcelik
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Incorrect coordinate transformation Gauss-Kruger - WGS84 using GeoTools

I´m having a problem concerning the beloved coordinate transformation with the aid of GeoTools: I would like to convert a set of coordinates from Gauss-Kruger (zone 5, EPSG 31469) into ordinary WGS84 coordinates (EPSG 4326). I´ve built a code with a…
sebjun87
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Point to great-circle segment distance

I want to calculate the distance from a point given by latitude and longitude to a line-segment given by two points (part of a great-circle). All coordinates are given in WGS84. I know how to calculate this in Cartesian coordinates but not on a…
user2033412
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Shortest distance between a line segment and a point in WGS84 crs using geotools api

In geotools you can find distance between two geometries using the distance function in Geometry class. There is a Point subclass of Geometry but no line segment subclass of Geometry. There is however LineSegment class which derives from LineString…
Haider
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How to convert wkt to jts geometry for a geography?

I want to convert a wkt geography into a jts geometry. I tried using jts wkt reader like this. import com.vividsolutions.jts.geom.Geometry; import com.vividsolutions.jts.io.WKTReader; Geometry geometry = wktReader.read(wktString); Here the problem…
geek2coder
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OpenLayers after call setCenter, map is still on 0,0 position

I tried to set map center by method setCenter, but still not working. Map is not moving. I tried to used transform from projection to map projection and without successful. Here is part of code. Thanks.