Tagged Questions

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

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Convert 2D coordinates from NAD83 to WGS84 using Postgis

I have a set of NAD83 coordinates that I need to convert to WGS84 coordinates. I am using postgis on an RDS. Specs for the box I am using from postgis_full_version(): POSTGIS="2.1.3 r12547" GEOS="3.4....
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Projecting NAD83 on-the-fly to WGS84 [duplicate]

I have a point feature class in a geodatabase that uses WGS84 as its SRS. A colleage of mine created points in this feature class using an external database containing lat and long values. However, ...
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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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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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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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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 ...
664 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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Transforming a PNG from RD_new to WGS84

I got the request to transform a PNG in RD_new to WGS84. Is this possible? I was thinking of changing the accompanied world file its coordinates. I do not think it is possible to load in a png in a ...
195 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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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 ...
827 views

ITRF2008 to WGS84 Datum Transformation in ArcMap?

If I have data in IRTF2008 as shapefile is it possible to change this to WGS84 and how? The need for this comes when trying to display the data in a third party program that doesn't recognize the ....
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how to transfer a geotif with WGS84 to a mercator array for ploting it with matplotlib.basemap

I want to plot data from a sensor raster file (tif) to a map using basemap. I have a geotif with 'WGS 84' >>> gtif = gdal.Open("example.tif") >>> print gtif.GetProjectionRef() ...
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Formulae to convert WGS84 coordinates (B,L) to spherical coordinates (phi,lambda)?

How to convert WGS84 coordinates(B,L) to spherical coordinates(phi,lambda)? I Need Formulae? the thing I'm wondering seems quite simple but I've been searching through internet and library of my ...
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Point-in-polygon using WGS84 geographic coordinate system

When running a point-in-polygon operation, is it valid to run that with polygon features in straight up WGS84 and a point in lat/lng, or should both be projected into a non degree based coordinate ...
162 views

J2000 to WGS84 in QGIS?

How to transform Earth-Centered Inertial J2000 CRS to WGS84 CRS in QGIS? I searched J2000 in spatialreference.org, however nothing found. I don't know the proj4 string of J2000. Any advice would be ...
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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 ...
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Is there an algorithm for transforming from CGCS2000 to WGS84?

Is there an algorithm that supports transforming from CGCS2000 coordinate to WGS84 coordinate? CGCS2000 is China Geodetic Coordinate System 2000. Any advice would be thankful!
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Transforming coordinates between wgs84 and UTM ED50 31N, what am I missing?

My problem is I must tranform a point cloud from wgs84 (geographic) to UTM (projected) ED50 for zone 31North. Easy, isn't it? Well, first surprise is I have several free webs who offer me this ...
2k views

Convert EPSG:3068 to WGS84

So I have a GeoJSON with EPSG:3068 and I would like to convert the coordinates to WGS84(EPSG:4326). I could also convert them before I write them to GeoJSON. I could not find an algorithm for the ...
617 views

How to convert the SRTM DEM orthometric to ellipsoidal heights using ArcGIS or others GIS?

Recently I got the SRTM DEM from Cgiar,which based on WGS84/EGM96. and I merged the tiles to one tiff file. I want to get the WGS84 ellipsoidal heights. According the steps from the Arcgis Help 10.2 ...
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Need advice for localized survey base point

I have a set of 4 control points used for H and V localization. There is a base point located far to the SW of the property. I did not create this myself, but took it off of an existing Pocket 3-D ...
1k views

PostGIS get geometries within a radius of n meters using WGS84 [duplicate]

select * from zones z where st_intersects(z.geom, st_Buffer(ST_SetSRID(ST_Point(2.336031, 48.863172), 3857),1)); It looks like the 1 in the st_buffer is being interpreted as degrees, I need to find ...
2k views

Merge geojson polygons with WGS84 coordinate

I have a Geojson file with some adjacent polygons and I want to merge them into one. I know it's a recurrent question but I can't find information for polygons with latitude and longitude coordinates ...
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Getting WGS84 height of a given place mark - Google Earth

Setting manually a place mark for a given location or obtaining the coordinates via Google Earth search yields the (Long,Lat) WGS84 coordinates. I'm fully aware of map is a 2D concept, yet is there a ...
1k views

Proj4js Problem in converting coordinates from google mercator

I am a really beginner into web-cartography, so sorry if this subject is rudimentary or basic but I truly search for a long time and I am still stick in it. So the problem is: I don't understand why ...
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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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Google Earth / QGIS projection (great circle line)

Here is my question: 1- Based on a long distance segment ( approx 2000 km) drawn on Google Earth and imported as shapefile in QGIS I want to obtain a terrain profile based on "Terrain Profile" plugin....
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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 ...
254 views

Problem with projection of Slovenian Shapefile in QGIS

I hope someone can help me for this: I'm doing my masters thesis in Slovenia (in the field of wildlife management), for this I got a Shapefile of slovenian data by the University. As a main layer, I ...
257 views

Should geometries be drawn using rhumb-line or great-circle paths?

I work with WGS-84 coordinates and, most of the time, my map display (luciadmap) is in Mercator projection. My client is surprised to see that, for a rectangular geometry: the line between the 2 ...
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The ratio Pixel distance to geographical distance?

I have had this problem for several days and I have no idea to solve it. The problem is that I am trying to find out the length and width of ships from a Bing map. I got the location point (lon, lat)...
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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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Is there a method to tell which hemisphere a point belongs to, in WGS84 geoid, where the equator is an arbitrary ellipsis?

I use the WGS84 geoid (because I'm working with a GPS chip). I define an ellipsis that splits the surface in two parts, lets name these 'A' and 'B'. This ellipsis is defined by two points 'a' and 'b'...
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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 ...
662 views

Projected coordinate system for South America

Does anybody have any suggestions for a projected coordinate system for the Northern part of South America? I have a data set that reaches from Venezuela to Southern Peru and I'd like to do some ...
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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 ...
442 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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Help projecting Austria data with QGIS

I'm trying to reproject this dataset from Austria Statistik Geodata. Data comes in "MGI_Austria_Lambert", and I'm trying to reproject to WGS84 What I'm doing is Saving layer as... and selecting EPSG:...
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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' ...
125 views

Google layers not matching

I'm working in a project with whole Europe data. I'm working with WGS84 (4326), and sometimes I overlay my polygons with Google maps layer (in QGIS) to see some details. When I do this, I have to ...
130 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 ...
235 views

Shape length distance wrong in Robinson projection

I have a world map in the WGS 1984 Geographical Coordinate System. I want to measure the lengths of borders between countries in kilometers. To get the units in meters, I have first used the Define ...
292 views

Comparing printed nautical charts to GPS coordinates

I'm just getting my head wrapped around the various geodesic systems. I have some (printed) Finnish nautical charts I'm trying to match to GPS coordinates. Given the number of underwater obstacles, I'...
279 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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Figuring out what coordinates supposedly using 'NAD31 projection' refer to

I'm working with a GeoJSON file that contains sets of coordinates associated with street corners in the city of Montreal, Canada. The spec sheet of the API delivering those GeoJSON specifies that the ...
378 views

Extracting data from Natural Earth using GeoTools java class?

I wrote a small java class to extract country boundaries from naturalearthdata.com data. My problem is that the coordinates do not match with OSM map, the whole polygon is shifted... e.g. according to ...
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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 ...
619 views

ArcGIS Conversion Error While Converting ED50 Datum to WGS84 Datum

With ArcGIS for Desktop, I tried a datum conversion of Transverse Mercator ED50 Datum to Transverse Mercator WGS84 Datum. Normally, the difference between two projections is approximately 180 meters ...