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

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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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1answer
124 views

Projection WGS 84 is slightly displaced referring to a hillshade in QGIS

I have a hillshade and a vector layer. The vector layer is slightly displaced referring the hillshade. About lat=100m and long=175m The CRS of the project is EPSG:3397 - PD/83 / Gauss-Kruger zone 4. ...
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1answer
525 views

How to make world file in WGS84 out of OpenLayer's Google Earth layers?

I would like to make world file out of OpenLayer's Google Earth. The problem is, that Google Earth layers in Qgis are shown EPSG:3857, but I need just standard WGS84 (ESPG:4326). When I try to set ...
3
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1answer
230 views

Why is my Polygon (WGS84) in SpatiaLite 4 not displayed by QGIS? [closed]

I made a polygon in a SpatiaLite 4 database as follows: INSERT INTO test_pg (id, name, geom) VALUES (3, 'test', ST_PolyFromText('POLYGON((8.556824 47.185269, 8.611009 47.185269, 8.611009 47.218568, ...
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2answers
525 views

What's the best projection for rasterization of random latitude and longitude data in the northern Atlantic?

I have a dataset in the WGS84 geographic coordinate system that I would like to interpolate along a grid using Python. It appears gdal_grid is not available through the Python bindings, so I plan to ...
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1answer
591 views

Convert Lat/Lon to Pixel-XY on cropped map

I've got a little problem. I have a GPX-Track containing LatLon coordinates based on WGS84. The track should be drawn on a cropped map, and for this, I need the pixel coordinates. The map tiles are ...
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1answer
3k views

What is the relationship between ITRF and WGS84?

Why are there people saying that "I am using WGS84(ITRF96)"? There are newer version of ITRF. Will WGS84 follow it? If so, what will be the influence to us?
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How do I get the area of a WGS84 polygon in square meters?

The following gives me the area of the polygon in square degrees: SELECT ST_Area(ST_GeomFromText('POLYGON((871325.790874952 6105405.3261047,871418.748307692 6105359.72944624,871346.22022442 ...
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0answers
98 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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1answer
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QGIS: On the fly projection from WGS84, 19 N, to Web Mercator. Do I need to define a new CRS with transformation parameters?

Workin in QGIS, I have a shapefile called "protected areas" of Dominican Republic, that was digitized from topomaps 50k. Shapefile is projected to WGS84, 19N zone. My problem is that when I load ...
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179 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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1answer
978 views

Transform Shapefile from WGS84 to NAD83 using QGIS? [duplicate]

Possible Duplicate: How to reproject a vector layer in QGIS? I have some shapefiles whose CRS is WGS 1984 and I have some shapefiles whose CRS is NAD 1983 State Plane Illinois East. I want ...
2
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1answer
268 views

How to convert NAV4 coordinate system to WGS84?

I would like to know whether it is possible to convert the coordinates given in a NAV4 coordinates system into WGS84. I could not find out what NAV4 is and if it is actually a standardized CRS. Here ...
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1answer
534 views

How to convert a geotiff from WGS84 to 3857 with gdalwarp?

I'm trying to convert images with WGS84 projection to 3857 but warp is not giving me a output I would expect. This is my command: gdalwarp -s_srs "+proj=merc +datum=WGS84" -t_srs "EPSG:3857" ...
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0answers
159 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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1answer
2k views

How to Project shapefile from NAD 1983 UTM Zone 12 to WGS 1984 UTM Zone 13N?

I have a question and I have a shapefile that is in NAD UTM Zone 12 and Datum is North American Datum of 1983. What I would liket to reprojection it to NAD 1983 UTM Zone 13N and change the Datum to ...
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2answers
520 views

Proper gdaltrasform syntax to transform a list of coordinates?

this is probably a very simple question, but I'm very new to GIS so I just need one last nudge. I've got a sense of the Linux utility gdaltransform and I am feeding it coordinate pairs in ...
2
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1answer
385 views

How do I convert EPSG:26986 coordinate pairs to EPSG:4326 from the MassGIS web service, the Linux command-line, or PHP?

I'm a GIS newbie, normally a PHP web applications developer. I am trying to map all boundaries of the MA state representative districts. So I just need to convert polygon coordinates from the ...
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3answers
2k views

How to convert projection

I got sample shape files with the following *prj file content: ...
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1answer
1k views

Python script to convert Lat Long to ITM (Irish Transverse Mercator)

I am currently working on a python script that converts Lat Long (WGS84) to ITM. The formulas used are based on a paper published by OSGB (Appendix B): ...
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2answers
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How to calculate new point coordinates from distance and angle using ArcGIS SDK for iOS?

I want to calculate the coordinates of a new point. What I have: The source point coordinates, the distance (meters) and the angle For example: I want to create a point within 100 meters and 45 ...
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159 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 ...
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3answers
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How to convert from EPSG:4326 to WGS84/UTM 32U?

I am unable to convert from the project's coordinate system to a different one using QGis 1.8.0. I have a .shp file with a certain coordinate system information (WGS84 EPSG:4326 according to qgis). I ...
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3answers
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How to convert Lat & Long from Onemap.sg to Google Maps

I have a set of address for Singapore, I would like to take the Lat & Long from onemap.sg (SYV21: X, Y / Easting, Northing) and then store it in my databse , convert into (WGS84: Longitude, ...
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2answers
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convert wgs84 coordinate to Google Map coordinate system(EPSG 3785) with geotools and java

Could you please point me out where can I make such a transformation: convert wgs84(EPSG 4326) coordinate to Google Map coordinate system(EPSG 3785), and vise versa. Thank you.
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Distances in {Plate Carrée projection - EPSG:4326 - WGS84}

So, "4326 is just the EPSG identifier of WGS84" [3], indeed http://spatialreference.org/ref/epsg/4326/html/ says it is a GEOGraphic Coordinate System: GEOGCS["WGS 84", DATUM["WGS_1984", ...
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0answers
351 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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0answers
800 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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OSM To Postgis & WGS84 problems

I’m trying to import OpenStreetMap (OSM) data into postGIS it doesn’t appear to be working in that features do not appear to be in the correct place.. Using the QGIS OSM add in and a coastal shape ...
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How are EGM96 and WGS84 related to each other?

As far as I understand the EGM96 defines the Geoid, where as the WGS84 Standard defines the Ellipsoid. Is the ellipsoid defined in the WGS84 standard defined in a way to maximize the congruency with ...
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Precision when working with spatial data in GIS

Is there a basic or introductory study that examines and compares the precision of spatial data when working with varying precison of the data input, like having 1, 2, ... decimal places? with the ...
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2answers
2k views

How is EPSG:4326 data 'projected' in a 2D map?

I like to think I'm relatively well-versed in datums, projections, and coordinate reference systems, so if this is a stupid question I will suffer eternal shame. OpenStreetMap data is stored in WGS84 ...
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1answer
990 views

Point of Intersection for a Ray and Earth's Surface

Say I have a ray vector originating from somewhere out in space. An example might be a ray of light from the sun. How can I calculate the point of intersection (if it exists) between the ray and the ...
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1answer
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Characteristics of different methods to convert ECEF to LLA

I'm trying to convert ECEF (Earth Centered, Earth Fixed) coordinates, which are defined in X,Y,Z, centered at (0,0,0) to LLA (Latitude, Longitude, Altitude). There are a couple of methods I found on ...
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Converting from British National Grid (27700) to WGS84 (4326) to Web Mercator (102100)

I'm developing a web application that uses ESRI ArcGIS to display a map using JavaScript. We are holding all our data in MS SQL Server 2008 as Easting/Northing against the British National Grid. ...
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2answers
6k views

How do you compute the earth's radius at a given geodetic latitude?

(I see there is an equation on wikipedia that does exactly what I am asking but there is no references. I have no way of confirming the validity of this equation!) I already understand the difference ...
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4answers
9k views

How do I calculate the bounding box for given a distance and latitude/longitude

Hi need to be able to calculate a bounding box or circle for a Given WGS84 latitude and WGS84 longitude, and distance but have no Idea where to start! The distance from the start lat Lon would be 10KM ...
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5answers
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Map projection in OpenLayers

I want to overlay some data whose projection is WGS-84 on Google map layer in OpenLayers. But I just can't make them in the right place. I did as follows: map = new OpenLayers.Map('map', { ...
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2answers
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ST_Distance versus ST_Distance_Spheroid?

As my client software uses lat/lon coordinates when communicating with my (spherical mercator) postgis database i decided to ST_Transform every geometry to WGS-84. However i noticed that ST_Distance ...
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1answer
506 views

Creating a User Defined Point Grid

Im trying to write some code (in C#, but any language will do) where the user defines and area, based on Min/Max Long/Lat's, and specifies a distance between points in meters, and the code returns a ...
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2answers
1k views

Converting Ordnance Survey raster maps to WGS84 webmap tiles

I would like to generate Google/Bing-like map tiles from Ordnance Survey's 1:25000 and 1:50000 raster maps, which are provided as 4000x4000 UK national grid tiles (GeoTIFF). A sample tile can be ...
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java vividsolutions jts wgs-84 distance to meters

my (java) project uses com.vividsolutions.jts.geom, which provides a distance function. After some googling I finally found that the return value from this function is in central angle degrees, when ...
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4k views

Convert Lambert Conformal Conic to WGS84

I am trying to convert my "Lambert Conformal Conic map with 2 standard parallels" to the basic/standard WGS84 projection that Google Maps use. I have 30 of these maps which I need to convert. They ...
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2answers
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Measuring distance between points in ArcMap - what coordinate system to use?

This is a basic -newbie - question. I have some handwritten data points taken off a GPS - so I am assuming they are in WGS 84, and I want to load them in ArcMap 9.3, via excel, and measure the ...
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1answer
324 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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3answers
3k views

Code to convert WGS84 coordinates to British National Grid Easting/Northings

I'm looking for some code, ideally C#, to convert a WGS84 coordinate to British National Grid Easting and Northings. Does anyone have this to hand? I tried converting the Javascript code here: ...
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1answer
622 views

Empty mapper window when I open a OSGB36 shapefile in MapInfo Professional. How can I see the data?

I have a set of shapefiles which I'm trying to open in MapInfo Professional 7.8. Each of the shapefiles has a .prj file which looks like this: PROJCS["British_National_Grid",GEOGCS["GCS_OSGB_1936" ...
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3answers
7k views

Converting X,Y coordinates to lat/long using pyproj and Proj.4 returns the wrong coordinates

I'm writing a python script that reads multiple XML files containing x and y coordinates and combines them all into a single csv file. Latitude and Longitude are required fields in the csv, but I am ...
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4answers
5k views

How to recalc WGS84 Shape_Area field to square miles in ArcGIS 10

What are the units of the Shape_Area field in a wgs84 feature class? Is it decimal degree squared? I would like to convert that to something more meaningful like square miles without reprojecting the ...
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1answer
924 views

Matching ArcGIS and QGIS coordinate systems

I have the following info for a feature class in ArcGIS that is supposed to be in WGS 1984/UTM 16N projected coordinate system: Projection: Transverse_Mercator False_Easting: 500000.000000 ...