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

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335 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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1answer
60 views

Find latitude of point on great circle given longitude

I am trying to find out wether my implementation has faults and/or if there is a better method. The problem: Given two points (Lat/Long) defined over the WGS84 ellipsoid, find the point lying on ...
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52 views

Unknown Coordinates

I'm new at gis. I'm using Arcgis 10.2.2 and trying to geocode some addresses. I used a geocoding service which gave the coordinates in this format: POINT(102778.307715144 105888.168842117) I don't ...
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1answer
119 views

Conflicting WGS84 coordinates between Trimble and Garmin GPS receivers

I am a contractor at a government facility in Nevada. We have our own in-house survey department who, for a number of reasons, still uses NAD27 State Plane Coordinates (Nevada Central Zone 2702) in ...
2
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1answer
241 views

Updating and exporting XY positions in UTM and WGS84 to spreadsheet using ArcGIS ModelBuilder?

On a daily basis I'm editing the geographic positions of various points of a shapefile (corner_XY.shp) by dragging them on my map. When this editing task is done I'm updating the points coordinates in ...
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1answer
1k 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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1answer
61 views

Unable to save to in Geojson format with the correct projection

I have a shape file (Polygon) in Qgis that I wish to save in Geojson in order to display it with the mapbox javascript api. Original projection is in POSGAR 97 My issue is that it does not reproject ...
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1answer
191 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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40 views

Converting between wgs84 and nad83

This is a newbie question that is about converting between wgs84 and nad83. I have aerial photos that I am trying to compute lat long coordinates for as closely as possible. There are several factors ...
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1answer
25 views

What is the formula for converting from WGS84 to EPSG:3071 (Wisconsin Transverse Mercator)

I have GIS software that can do this conversion but I need to know the actual formula / math involved. I'm writing code and need to perform a single conversion (WGS to EPSG:3071) so using a library, ...
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1answer
230 views

Converting WGS84 points to a 2D x,y point (plotting)

I have been trying to convert the WGS84 style geo-positions to x,y coordinates on a 2D plane. I have looked into many different links, websites, studies and I honestly gave up on finding a plane copy ...
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52 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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907 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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0answers
97 views

Returning distances in meters from Near (Analysis) tool of ArcGIS for Desktop?

I'm trying to write a python program that returns the distance from each point in a set to the nearest road. Specifically, I was looking for any points within 10 meters of the roads. Both sets of ...
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0answers
59 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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0answers
132 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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0answers
677 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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0answers
101 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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183 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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0answers
843 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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0answers
21 views

Determine lat/lon intersection on earth from point in space along 3d line

I have a known point in space with a lat,lon,alt. It has a camera with a line of sight and a angle of field of view. I can take the central point and calculate each corner vector of the field of view, ...
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42 views

convert headerless flat binary files to tif

I have set of headerless flat binary files (those are out put files of TIMESAT software). I want to convert those to .tif format. I did it using ENVI. but it does not overlap with the original input ...
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0answers
53 views

My map is little bit off

I am pretty new in GIS things and i have been learning how to use QGIS. Most of the maps are fine, but yesterday I went to GIS center at my University and I got the maps of my country that I will be ...
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100 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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191 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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390 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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0answers
162 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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367 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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32 views

WGS 84 - NAD 83 with a twist

I have a dataset of GPS field point collected received in WGS 84 but displayed in NAD 83 UTM. I used a field point to inform a total station for a reference starting point, so all my total station ...
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63 views

How to convert between SWEREF99 TM (GRS80) and long-lat (WGS84) coordinate with JMapProjLib (Java version of Proj4)?

I'm making an android app which is reading SWEREF99 TM (GRS80) coordinates from a file, but I need to convert them to long-lat (WGS84) coordinates, and also in the oposite direction (WGS84 -> GRS80). ...
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33 views

Closest line, line intersects box and general help

I've been knee deep in information about Geo data, projection and topography but can't find a simple library/method to help me with basic calculations of coordinates. I'm using Google Maps API in ...
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33 views

Pros and Cons of a latitude adjustment grid vs other methods of area calculations

When working with high resolution global raster data in WGS 1984 I often need to calculate areas. Now the traditional way for me to achieve this has been to reproject the data to an equal area ...
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44 views

Node.js transformation from NAD83 to WGS84

I've used the excellent npm shapefile library to import Canadian electoral districts into MongoDB. Here's a sample file: http://ftp2.cits.rncan.gc.ca/pub/geott/electoral/2011/fed308.2011.zip Is ...
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23 views

Setting correct units for Near tool?

I need to use the near tool to calculate distances between data points and a stretch of coastline. My problem is that when I run the function, the values that come up in the Field of the points' ...
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102 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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113 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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166 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 ...