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

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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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31 views

How to project SRTM DEM data?

I am trying to project a SRTM DEM file (raster format GRID) that covers my study region to a better projection and I hope with this I will figure out the cell size in meters. The DEM is currently in ...
7
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2answers
91 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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0answers
41 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
49 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
34 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
23 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
58 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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19 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
56 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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33 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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16 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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8 views

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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32 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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146 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
48 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
34 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
188 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
52 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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1answer
41 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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31 views

which projection are best for large continents [closed]

which projections are best for large continents and mid-latitudes
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58 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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110 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 ...
3
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63 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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72 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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64 views

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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156 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
527 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
109 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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789 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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40 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 = ...
3
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1answer
2k 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
56 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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11k 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 ...
2
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1answer
130 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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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
207 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 ...
3
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2answers
637 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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1answer
45 views

Converting UTM55 to WGS84 in ArcMap? [closed]

I've got a raster in UTM55 over Australia and I would like to convert it to WGS84. Any idea how to do it ? The problem starts when ArcMap recognize it as 'Geo-Reference' only and not as UTM55, so I ...
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2answers
198 views

Projecting shapefile with unknown CRS to WGS84 using QGIS?

I've tried setting QGIS to on the fly, changing the layer settings, nothing. I'm at a lost cause. Although I am not a GIS professional. ...
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2answers
222 views

MODIS-Sphere to WGS84 coordinate system in ArcGIS [duplicate]

I want to overlay two global raster datasets on land use which use different coordinate systems (MODIS-Sphere & WGS84) using ArcGIS Desktop. There seems to be no direct transformation option from ...
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1answer
92 views

Converting x,y on mercator to WGS84 latitude and longitude

How do I convert a particular point on a Mercator map (points in a Mercator map svg) to WGS84 coordinates? Is it simply a direct translation of the x,y values, using a multiplier which matches the map ...
2
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3answers
206 views

Mis-aligned shapefiles in QGIS?

I'm a beginner at QGIS and I'm having trouble aligning my shapefiles. I have two datasets: one originally in WGS84 (lat/long) and another in Corrego Alegre/UTM zone 24S. I need to convert the second ...
3
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1answer
132 views

Is re-projection needed from SRID 4326 (WGS 84) to 4269 (NAD 83)SRID

I have US census data against state boundaries stored as SRID 4269, in an MSSQL DB. The input data used for calculations against that dataset is stored as SRID 4326. As far as I can infer from the ...
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1answer
199 views

Transforming from EPSG:2154 to EPSG:3857 using ProjNet4GeoApi/Proj.net, C#

I don't have much experience with GIS. Here's are my projections defintion: private Dictionary<CoordinateSystemStrings, string> CoordinateSystemStringDictionary = new ...