Questions tagged [mercator]

The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator in 1569.

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Use ST_DWithin on WGS84 geometry data

I've just used osm2pgsql to import osm data to a PostGIS database, using lat/long option to store it in WGS84 projection. I would like to use ST_DWithin to select nodes close to a random point. When I ...
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2 votes
1 answer
109 views

Mercator vs Lambert Conic Conformal Projection

I am using coordinates in WGS 84 (coordinate reference system EPSG:4326). Unfortunately I am not very familiar with the different projections and currently do not see the wood for the trees. Is EPSG:...
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How to convert transverse_mercator to regular lat/lon

I want to transform this file from transvers_mercator to a regular lat/lon netcdf file. My input file: netcdf toto { dimensions: x = 548 ; y = 704 ; variables: char transverse_mercator ; ...
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What does the coordinate values represent when using WGS 84 / Pseudo-Mercator (EPSG:3857)?

I have been using QGIS for a couple of weeks now, mostly for data collection in my research project. Currently, I'm trying to plot these points, in a graph similar to this one (but in kilometers), I ...
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1 vote
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How to "unravel" a polar continent (i.e. Antarctica) from azimuthal projection and convert it into equirectangular?

I have very recently gotten into cartography and map projection, and I wanted to visualise the map from Avatar: The Last Airbender into a proper equirectangular map. Here is the map for those ...
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2 votes
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110 views

Meridian Convergence in UTM and Gauss Kruger Projection system?

There are points where geographic coordinates (latitude and longitude) are known. I have calculated the UTM (Universal Transverse Mercator) projection coordinates of these points and then I want to ...
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201 views

Calculating latitude from X,Y-coordinates on Mercator projection

I have a task to create a map of a specified section of the world. In particular, I need to map everything between the 120E and 100W longitudes and everything between the 60S and 30N latitudes mapped (...
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1 answer
291 views

GeoJSON coordinates transformation to Web Mercator coordinates

I'm not sure how OpenLayers is converting the raw coordinates from a GeoJSON's geometry.coordinates property into a Feature's extent property. I can't really seem to find a lot of documentation on it ...
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QGIS buffer distance parameter

This is very intriging, I don't remember having seen this before. I am working with the Vector -> Geoprocessing Tools -> Buffer tool in QGIS (2.8.6-Wien) If operating in British National Grid ...
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Satellites GOES16 and 17 - reprojection to Mercator is stretched

I have downloaded GEOS data from https://cdn.star.nesdis.noaa.gov/GOES16/ABI/FD/ (or https://cdn.star.nesdis.noaa.gov/GOES17/ABI/FD/). I want to reproject the disk to Mercator projection. I have used ...
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1 vote
1 answer
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Transform equirectangular simple TIFF to Mercator projection with gdal_translate / gdalwarp

I'm trying to transform this shaded map of Venus, a 2000x1000 TIFF in what I believe is equirectangular projection, without GIS metadata, to Mercator. I first tried gdalwarp -s_srs EPSG:4326 -t_srs ...
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Distance difference when moving longitude in maps services [closed]

I try to get two juxtaposed tiles in maps services like Google Maps or Bing Maps at a given zoom level (20 in my case). I managed to do it with those methods: def meters_per_pixel_NS(lat, zoom): ...
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Optimizing projection for accuracy in calculating distances

I receive a set of LatLong points and I want to optimize the projection to Euclidean points so as to try to keep (distance in Euclidean space)/(greater circle distance in latLong) with variance as low ...
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3 votes
1 answer
280 views

Generate EPSG:4326 Vector Tiles

My goal is to create EPSG:4326 vector tiles (using Plate Caree) that can be served in Leaflet. I currently have a .shp file, which I converted to a geojson file using ogr2ogr. The main obstacle to ...
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proj: Oblique Mercator specifying two points on central line

I'm trying to use Oblique Mercator in QGIS 3.4, which uses proj to calculate coordinates conversion. I specify two points in the central line, rather than specifying the center and alpha. Oblique ...
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Converting X and Y coordinates from Mercator world map (square) image to Latitude and Longitude

I'm using the following JS to transform Latitude and Longitude to X and Y coordinates but now I need the contrary, transforming Latitude and Longitude to X and Y. export const latLon2xy = (lat, lon, ...
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2 answers
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Converting between coordinate systems but retain visual shape? [closed]

We have some data that is stored in GeoJSON format (using EPSG:4326), but now we want to display the data in the mapbox-gl-js, which only supports EPSG:3857 for display (support for other projections ...
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3 votes
1 answer
1k views

Using project / layer CRS in QGIS?

I'm using QGIS 3.4.1, and I'm trying to print 61km x 61km area map of somewhere South Korea. Then I need to send this map with west / east latitude and north / south longitude info to other person, ...
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Regular grid for whole planet

I`m trying to generate rectangular grid for whole world with fixed cell size in 350 meters (width and height are equals). What i tried to do: 1) in main loop iterate trough longitude in range [-180; ...
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Mercator map coordinates transformation formula

I have a third-party application with a city map of size 131072x131072. There are data on this map which contains x and y coordinates. I want to transform these coordinates to latitude and ...
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1 answer
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Angular rotation using Proj4, for local coordinate system

I have a polygon feature on map to which I need to transform the coordinates to local coordinate system with respect to new origin while keeping the same datum. So far using the Proj4 library and by ...
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Map camera image onto sphere

How would I determine what the red point (phi', theta') is for a camera oriented at a known (phi, theta) is from a given image? The point of this is to determine what (dphi, dtheta) is so that I can ...
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355 views

Calculate Latitude based on a mouse position on Mercator map

I have a similar question to the one found here, Mercator projection: formula for latitude based on pixels? The answer was very helpful but my question is just different enough that it doesn't quite ...
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1 answer
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Straight lines plotting as curves

I'm trying to do something really simple, plot a rectangle using psxy on a .cdf grid file. Something like: grdimage grid.cdf -JM20c -R-70/0/20/60 -Bf20g10 -K > image.ps psxy rectangle.dat -JM -R -B -...
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C# - convert lat long coordinates to WKT format

How can I convert coordinates to WKT format like 39.8251136,-8.3824103 with 900913 system (spherical Mercator)? My client is askying me something like this: SRID=900913;POINT(-939520.0088637 4744291....
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1 answer
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Mercator - create uniformly distributed dots over map

I have a map in Mercator projection. I know coordinates of corners. I want to render uniformly distributed dots to map. for (float latDeg = startLatDeg; latDeg <= endLatDeg; latDeg += stepLatDeg){ ...
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127 views

Problem with parseWKT : projection mercator-2SP

1 -CoordinateReferenceSystem crss = CRS.parseWKT("PROJCS[\"Mercator\",GEOGCS[\"WGS 84\",DATUM[\"WGS_1984\"," + "SPHEROID[\"WGS 84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]]," ...
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2 votes
2 answers
165 views

Why maps package adding straight lines in North America using mercator projection in r?

Why is this code creating a bunch of lines crossing the map? map(database = "world", proj="mercator", fill=FALSE, bg="white", resolution=0) How can I remove it without changing the ...
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0 votes
1 answer
60 views

problem converting OTF from Mercator to equal area

QGIS 1.8.0 on OSX 10.10.5: I've got continent outlines from Natural Earth that are in EPSG:4326 (degrees) plus USGS tree range data in EPSG:2030 (also degrees). When I set the project CRS to EPSG:4326 ...
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6 votes
1 answer
2k views

Converting EPSG to D3.js

Given an EPSG projection (say, this Alabama one: http://spatialreference.org/ref/epsg/26729/) How can you take the given WGS84 projection bounds in such a way that you can use them in a D3.js ...
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0 votes
1 answer
3k views

Convert lat/lon to Mercator x/y, then measure distance

I'm attempting to convert latitude/longitude coordinates to X/Y coordinates on a 52,000 sq. ft. grid according to a simple Mercator projection. I used the following Python code to accomplish this, ...
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a localised 2D coordinate system from GPS coordinates

I spend a few days reading about coordinate systems, map projections, datums, etc. Since I am new to gis, I am not confident I am doing this right. Problem at hand: I have a GPS device that gives ...
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0 votes
1 answer
358 views

Generating perfect tile set from Mapbox for given zoom level?

I'm using Mapbox API to generate bitmap tiles. First of all I have generated whole world tile with zoom 1 (seems it doesn't matter 0 or 1) and resolution 1280x1280. This tile perfectly positioned from ...
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3 votes
1 answer
457 views

gdal2tiles pixel shift in output tiles

I would like to re-calculate large geotiff files (10,000 x 10,000px) with the help of gdal2tiles into little (256 x 256px) tiles. The process works fine. However, the result is not perfect. There is ...
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4 votes
2 answers
3k views

Using pyproj and Mercator: x_0=0 and y_0=0?

I'm having a hard time figuring out how to project correctly from a Mercator projection to LAT/Lon. Basically, I have a netCDF file with the following variables: LON0 = 42.0 => reference longitude ...
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19 votes
1 answer
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How does what3words build a grid of squares on the surface of the Earth?

What3words built a grid of squares of 3m2 on the earth. Does anyone know what is the algorithm ? I started with this method: the range of longitude is [-180, 180] and the range of latitude is [-90,90]...
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3 votes
1 answer
2k views

How a draw a circle (on the surface of earth) on a mercator projection?

I would like to use R and leaflet to draw a circle (a real circle on the surface of the earth) on a mercator projection. In the following code, I have the center of the circle (with lng=0 and lat=60),...
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2 votes
0 answers
187 views

QGIS Qtiles from EPSG 3395

I am having issues while converting my layer from 4326 to 3395. My Qtiles does not make tiles. I have a source mapinfo in 4326 with long, lat pairs. My goal is to show this on a maps.yandex (3395 ...
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9 votes
2 answers
6k views

What's the accuracy of Web Mercator EPSG:3857?

Are there any references on the accuracy or (min/max/avg) error of Web Mercator when it comes to e.g. distance calculations? For the sake of completeness, I haven't found any reference to the ...
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2 votes
1 answer
446 views

projecting onto Cartographic coordinates using Gauss Conformal Mercator in python

The shapefiles and boundaries I work with are on WGS 84 referenced to SA: GEOGCS["WGS 84", DATUM["World Geodetic System 1984", SPHEROID["WGS 84", 6378137.0, 298.257223563, AUTHORITY["EPSG","7030"]], ...
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3 votes
1 answer
2k views

How to quickly change EPSG in QGIS (Openlayers; 4326 vs. 3857)

I'm using Qgis 2.12.2-Lyon on Ubuntu 14.04 LTS. With the OpenLayers plugin I added some OpenLayers to my Canvas. I usually use the WGS 84 (EPSG:4326) projection for my project, but I have to switch ...
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6 votes
1 answer
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Transforming lat and long to Mercator x and y

I've been trying to plot a set of lat and long coordinates to a Mercator map using the following set of equations: x = long - long0 y = ln(tan(pi/4 + lat/2)) These equations are from a page on ...
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1 vote
1 answer
1k views

Formula of mapnik bounding box (spherical mercator)

I want to implement a tile server and I'm following the code in the repo node-mapnik-sample-code. When a request is sent with the parameters x, y, z (longitude, latitude, zoom), those parameters are ...
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2 votes
1 answer
1k views

Map scale factor when converting from Mercator to Equirectangular

Lets say I have a map in Mercator projection, and I know top and bottom latitudes: topLatitude = 80; bottomLatitude = -55; I also know width and height of a map: width = 800; height = 500; I want ...
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2 votes
1 answer
5k 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 ...
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1 vote
0 answers
844 views

Geoserver Mercator to EPSG:4326

I have external WMS server, which have a layer pusblished in Mercator projection (EPSG:3395). I have this layer set up in Geoserver (2.8.1, GeoTools 14.1). I need to expose this layer via WMTS in ...
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364 views

Flat Map that can go thru North Pole

Is there any map SDK or tool that can show the navigation that passes through the north pole in a flat way? Basically If I use a Mercator projection map it is only flat and cannot show the north part ...
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1 answer
8k views

How to make a point from real latitude and longitude values

My program has a center point and one moving object . At this moment this point is somewhere in Europe.But Now i have to change that point from the latitude and longitude values(of Australia) . Please ...
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5 votes
1 answer
519 views

How to center a user-defined CRS on an area of interest?

My study extent in central Iran straddles two UTM zones (39 and 40): I would like to create a user-defined CRS in Transverse Mercator projection with central meridian inside this area. Through ...
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3 votes
3 answers
9k views

Calculating Mercator coordinates from lat/lon

I am new to GIS but I am working on a project mapping a building using floor plans and JOSM. Using the PicLayer plugin I added the .png floor plan as a layer. I wrote a .cal file to set the scale, ...
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