WGS84 is a geodetic coordinate system, the World Geodetic System 1984 (EPSG:4326).

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How much error is should occur when using WGS84 to ECEF coordinates?

I am creating geoinformatics software and have found the appropriate formulas for converting Wgs84 to ECEF. I've checked my outputs against various sources and they seem to be correct. However the ...
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31 views
+50

Where to get world-map images for use in webglearth

I am using webglearth for a 3D earth globe. I already bought MapTiler, from the same makers. Now I am struggling with finding different world-map-images with the right projection. I need either WGS ...
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1answer
927 views

Finding projection of point to line?

I have a segment defined by 2 LatLon points(A and B) and a third LatLon point (C). I need an alghorithm, formulae, or some code to find the projection point of C on the segment AB (call this point D) ...
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23 views

KD-Tree implementation with lat/lon coordinates

I have implemented a KD-Tree that stores coordinates (latitude, longitude). I have also implemented a Nearest Neighbor search algorithm using the Haversine distance. Will I get correct results (same ...
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2answers
36 views

Coordinate System Mismatch

I understand that coordinate system mismatches between layers is a relatively common problem. Nevertheless, exploring other posts hasn't helped me understand my issue. In short, I have a DEM raster ...
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1answer
329 views

How do I figure out the length of polyline features in a feature class with a WGS 1984 coordinate system?

I'm trying to figure out lengths of polyline features in a feature class with a WGS 1984 coordinate system. Here's code to list lengths: >>> import arcpy >>> inFc = ...
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1answer
32 views

Conversion from WGS84 to UTM NAD83

If all my data is in UTM NAD83 Zone 10 and I get new data in GCS WGS 1984 do I have to reproject the WGS data to UTM NAD83 Zone 10 for it to align correctly or can I just bring it into an mxd that is ...
3
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1answer
45 views

Converting a NAD27 Lambert Conformal Conic custom projection to WGS84 using QGIS

I am trying to convert some points from NAD27 Lambert Conformal Conic (custom projection) to WGS84 using QGIS 2.8.9. I am using the datum transformation parameters for El Salvador published here: ...
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2answers
572 views

Project twitter geo data into WGS84 map

I'm currently working on displaying twitter geo data (currently just long/lat -> cartesian without any analysis). This is the world map (source: naturalearthdata): ...
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1answer
811 views

Raster and vector layer in the same CRS don't match

While adding multiple raster and vector layers (and setting them all in CRS WGS84) in QGIS 2.2, they don't seem to overlap. Interestingly enough, only raster files overlap between each other, the same ...
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2answers
104 views

Polygons across international dateline [-180..+180 longitude]

I'm trying to generate polygons for satellite orbital swaths. So far I have a method to generate two lines which represent the edge of each swath in [lat,long]. Some of the swath's cross the ...
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45 views

Triangulation of Cell Towers using MSQL Server Spatial

I need to triangulate a GSM Device by using known cell towers locations and GSM readings. All Data is in a MS SQL Server as Geometry Types. herewith an example of the data : here is also a SQL ...
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1answer
51 views

Finding the origin in .laz file with LAStools

I obtained a .laz file, which I used lasinfo and las2txt to view the records. Scale Factor X Y Z: 0.00100000000000 0.00100000000000 0.00100000000000 Offset X Y Z: ...
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1answer
40 views

Reprojecting: trouble converting MapInfo data to shapefiles in QGIS

I was given a dataset generated in MapInfo. I need to use these files in QGIS, so I imported the .TAB files and saved them as ESRI shapefiles. I then realised the original dataset uses a custom "user ...
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1answer
32 views

Negative coordinates for WGS84 system are invisible - ArcGIS 10.2

I have a csv file with point coordinates in GCS_WGS_1984 geographic system. I've imported it to ArcMap as a XY file however negative values for West hemisphere are not visible (but ALL records are in ...
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1answer
61 views

Converting GeoTiff to UTM in QGIS is slow?

I am trying to convert a Geotiff from WGS84 to UTM17. In QGIS, there seems to be a super easy way to do this: First, I input my tiff by clicking add raster layer. This works successfully, as I can ...
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1answer
2k views

PROJ4 C++ API: Amersfoort RD New to WGS84

I try to convert between dutch RD New (EPSG:28992) and WGS84 (EPSG:4326) via PROJ4 C++ API. On the console this works with: cs2cs +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 ...
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25 views

Converting from ellipsoidal heights to orthometric heights (EGSA87)

I try to conver from ellipsoidal to orthometric heights with arithmetic function. In input raster 2 i put WGS84.img from \peodata\geoid folder.The results are not right. And now i have the question. ...
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1answer
69 views

Guessing unknown projection in Malaysia

I have a database of northings and eastings of boundary markers of land parcels that are in a form that I cannot pin on any format. I would like to perform some conversions on them so that they can be ...
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1answer
36 views

How to divide line into three equal parts?

I have a problem with line division. I'm writing a program in JS/C++ generating KML files. I was trying to divide a line using my own function (which is correct on cartesian space): var part1Lon ...
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19 views

Can I assume that ENU Coordinate are already projected?

I have an application where I need to track a vehicle position in range of max 50km. I implemented the ENU coordinate system so my future calclutaion would become easier to impelement (e.g. generating ...
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from/to ellipsode to/from cartesian conversion

i am trying to convert from/to ellipsoidal coordinates (lat,lng,alt) to/from cartesian(x,y,z) i wrote the below code to do the conversion, but given the initial values of the gpsLat and gpsLng i ...
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1answer
35 views

convert REGCAN95 coordinates to OpenStreetMap coordinates (WGS84-Form in lat/long)

I have some coordinates in datum REGCAN95, and I want to know how to convert them to something usable in OpenStreetMap. I have found that REGCAN95 uses the EPSG codes as follows: 4082 REGCAN95 for ...
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1answer
23 views

Given WGS84 bounding box, is there service that returns most accurate projection to use?

I'd like to find a service to convert lat/lon in WGS84 to an arbitrary coordinate system in metric that will be the most accurate for my bounding box. Does something like this exist? For instance, ...
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1answer
38 views

confused about distances on the wgs-84 ellipsoid

As far as I understand given a certain latitude the length of a degree of longitude is constant. So using any distance calculator (I use Mathematica here) this equals: (circumference of the earth) ...
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150 views

Is WGS 84 datum, coordinate reference system, or both?

The background to this question is in Understanding difference between Coordinate System and Projection? There @mdsumner commented: WGS84 is not a cs, it's a datum. On a couple of places online ...
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1answer
52 views

Create grid from raster with equal size squares

I have a raster of the globe with coordinate system WGS_84. I want to create a grid on that raster where every square has the same size. When I use the Create Fishnet tool the size of squares get ...
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1answer
39 views

How to calculate areas for data that covers the whole of Australia [duplicate]

I have a polygon shapefile showing mining areas across all of Australia. I want to calculate the area for each of the polygons however they have been provided in a Geographic Coordinate System ...
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3answers
211 views

What is the Origin of WGS84 UTM 18N?

I was given an unprojected coordinate in the form of lat, lon and I am using pyproj to convert to projected coordinate as such: from pyproj import Proj # New Jersey lat = 40.704895 lon = -74.094994 ...
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3answers
1k views

Proper gdaltransform 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 ...
3
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1answer
55 views

Why does QGIS do an unintended datum shift to WGS84 in the map canvas

I'm a new QGIS user running 2.12 Lyon. I've encountered an issue with map canvas units and an unexpected and transparent datum transformation to WGS84. I need help figuring out if I've missed ...
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48 views

Failed to export vector file from OGR?

I use to transform data points from UTM (WGS84) to WGS84 EPSG:4326. Basically from UTM to Geographic coordinate system both in (WGS84). I tried to do it again but an error message appears. ...
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32 views

which projection are best for large continents [closed]

which projections are best for large continents and mid-latitudes
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71 views

WRF Spherical Earth to WGS 84

Weather Research Forcasting Model assumes a spherical earth model with a radius of 6370km. I'm looking to display the data onto the WGS-84 Ellipsoid model as that is the model my system uses for its ...
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123 views

Convert WGS84 coordinates to ECEF Cartasian (XYZ) coordinates using pyproj

I need to convert WGS84 to ECEF to map some points to a 3D sphere. I've trawled through the pyproj docs, but can't find specifics on the matter. Basically I want to input the WGS84 GPS lon/lat ...
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3answers
3k views

Transform from WGS84 to EPSG 3785 (google maps)

I am a Java Developer and I was given this coordinates from a database verbat_sistema_coordenadas verbatim_SRS datum verbat_longitud verbat_latitud UTM WGS84 ...
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1answer
70 views

Checking if two WGS84 lines intersect in JavaScript

I am trying to work out given two GeoJSON lines (WGS84), if they intersect (i.e. cross one another). Let me give some pseudocode to illustrate: // Providing Line 1 = lon1, lat1 and Line 2 = lon2, ...
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77 views

projection (WGS84, UTM) issue

I have a question about projections. I have a hillshade raster with UTM 31N projection (I reprojected this from WGS 84). I also have a satellite image that I need to georeference. For georeferencing I ...
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Find gravity normal by ECEF or GPS coordinate of point

How to find gravity normal by ECEF or GPS coordinate of point? Is it the same as normal to elipsoid? Is this ordinary way to calculate normal to ellipse? I'm not quite sure which altitude is ...
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165 views

Is a Helmert transform necessary to convert between WGS84 and NAD83?

I've read things all over the internet which claim that NAD83 and WGS84 are effectively equivalent (with minor ellipsoid differences). However, if I do geodetic (WGS84) -> ECEF -> geodetic (NAD83) ...
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2answers
576 views

Making Fishnet that is specific size in square meters on ground?

I have a raster image in GCS WGS 1984. For sampling I want to take a grid of 500 m^2 in my area of interest and pick the centroid of this square. How do I make sure that the grid created with Fishnet ...
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3answers
132 views

Area units for output polygon in WGS 84 UTM Zone 32N using QGIS

I am calculating the area of my polygon and I have used WGS 84 UTM zone 32N to calculate the area (using geometry on the field calculator) of my polygon, and I obtained 745461 (without units). How ...
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1answer
797 views

Converting Lat/Lon to Pixel-XY on cropped map?

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 from OSM I'm not quite sure ...
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46 views

Can I use a polygon envelope I get from JavaTopologySuite(.NET port) in an R-tree implementation? (wgs84 to spatial)

I'm using this implementation of https://github.com/enyim/RTree. I use the .NET port of JavaTopologySuite to create some polygons and then get their bounding rectangles. IPolygon p = ...
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1answer
3k 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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63 views

JTS polygon intersection calc on a geoid

I am using JTS to compute intersections between polygons with WGS84 lat/lon coordinates. I am not converting coordinates to anything 2D based, just reading in POLYGON(lat lon, lat lon) and doing ...
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3answers
12k 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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1answer
185 views

Relation between Geoidal separation and antenna altitude in GGA sentence?

I have searched about definitions and relations about geoidal separation and antenna altitude reported in GGA sentence. The more I read the more I am confused.So in a simple manner can anyone explain ...
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4answers
9k views

What is the projection of WGS84 in GIS software?

WGS84 is a reference ellipsoid that determines coordinates of every point on Earth using latitude, longitude and height about the its surface. This ellipsoid is often used as a base to make maps. ...
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2answers
218 views

Why do MGI and WGS 84 data not line up in ArcGIS for Desktop?

When i reproject raster from MGI 6 zone to the WGS84 it makes a mistake (it is moved for 380 m )See example below: I know that the problem is in MGI 6 projection (it is not accurate),but I do not ...