The coordinate system known as World Geodetic System 1984 (EPSG:4636)

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284 views

What is the DNSC08 Mean sea surface model ellipsoid based on?

Does anyone know what Danish Space centre DNSC08 mean sea surface model uses as the reference ellipsoid? there is no meta data on the web site: ...
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526 views

How to convert (geodetic pose + cartesian offset) to geodetic position

I am in search of an algorithm to solve the first/direct geodetic problem precisely in 3D. The input is: a geodetic (not geocentric) position (WGS84, height is above the WGS84 reference ellipsoid) ...
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62 views

How to draw an arc by centerpoint, radius and azimuth in KML

The question is how to generate lon/lat coordinates for an arc/sector. Coordinates can be used/filled into a KML file. Pointers to geometric formula or a program applying the formula are much ...
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44 views

problem creating and editing features at extent edges

I'm in the process of creating a polyline feature layer of tectonic plates. I'm working with WGS-84 reference system, which means the extent is +-180 in lon, and +-90 in lat. In order to create the ...
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633 views

Bearing/Course/Heading in WGS84 ellipsoid model

There is a common formula for computing the initial bearing for a course from lat1, lon1 to lat2, lon2. (And yes, I'm aware that the course will change when traveling). atan2( sin(lon2-lon1) * ...
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46 views

Re-projecting WGS84 to OSGB in SAGAGIS

I took some points with a GPS, and I'm trying to convert from GCS to OSGB 1936 British National Grid in SAGAGIS. I'm working with a shapefile. To reproject the vector layer to the OSGB projection I ...
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108 views

Height of the geoid in ECEF coordinates

I know that the relationship of geoid height N and ellipsoid height h to orthometric height H is defined by H = h - N, but what if I have some position in Earth-Centered-Earth-Fixed (ECEF) ...
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450 views

Projecting a Raster from WGS84 to planar Equal Area to Calculate Area: How to Select the Cell Size?

I have a broad question on how to calculate the 'correct' cell size for a raster when analyzing an area not at the equator. My goal is to project a land cover raster provided in GCS WGS84 to an equal ...
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89 views

is ellipse inside ellipse in WGS84 ellipsoid

My question is quite clear: Assume that there is an ellipse, namely EL1. Parameters of the ellipsoid are (focus11 [latitude, longitude], focus12[latitude, longitude], radius1). And a second ellipse, ...
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155 views

projection discrepancy with gdal (1.9) and proj4

I boiled the problem down to that python example: import sys try: from osgeo import gdal from osgeo import osr except: import gdal import osr if __name__ == '__main__': version_num = ...
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695 views

OSGB36 to WGS84 reprojection 'error'

First off, I am a recent convert to QGIS and am greatly impressed with its ease of use and speed compared with the ESRI products with which I am more familiar - my congratulations and thanks to its ...
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26 views

SRTM elevation data question

I have a question concerning the SRTM elevation data (http://srtm.usgs.gov/). As a little thought experiment, assume I want to build a 3D model of the earth's surface as a point cloud. The earth's ...
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137 views

GeoTools: SimpleFeatureCollection to KML error CoordinateReferenceSystem

I want to export a SimpleFeatureCollection (Read from a MySQL DB) to a KML file, here is my code used to read the infos into the console: private void featureCollectionToKML(SimpleFeatureCollection ...
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328 views

Get the distance between 2 WGS84 GEOSGeometries

I currently want to check if 2 given GEOSGeometry objects of type Point are within 100m of each other. (length flexible) Looking at previous asked questions on this topic, most of the answers were ...
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151 views

Convert MapCoordinate from WGS 84 and vice versa - ESRI MOBILE 10.0

I am seeing a strange issue in 10.0 mobile version. If a convert a coordinate (x.x,y.y) to WGS84 using mobilecache1.spatialreferece.towgs84 and if I convert the resulting GPS coordinate back to map ...
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319 views

Conversion From Transverse Mercator To Longitude & Lattitude

I have to transform (7-parameters datum transformation) coordinates from northings & eastings to lattitude & longitude. Following are details of source coordinate system(i.e. northings & ...
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69 views

How to determine the Geoid model used by GPS receiver?

I have the following NMEA output by Holux M-241 GPS receiver: $GPGGA,144014.000,2227.0987,N,11410.1382,E,2,6,1.67,32.6,M,-1.3,M,0000,0000*7B I know that WGS84 height is higher than geoid height 1.3 ...
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77 views

issue with QGIS Scale Level

I have different layers of shape files. I have imported all shape files into PostGIS. Now i want to show 3 layers Country, State & District with different scale/zoom level I tried to set scale ...
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151 views

QGIS 1.8 problem with rendering polygons in WGS84 on Ubuntu 12.04

I'm using QGIS 1.8 on Ubuntu 12.04. If I add a polygon layer in SHP format and WGS84 projection and start to zoom in, from a scale of 1:200.000 aprox. polygons on the edges are not drawn anymore and ...