Skip to main content

Questions tagged [mercator]

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

Filter by
Sorted by
Tagged with
0 votes
0 answers
36 views

Hotine Oblique Mercator projection Where is the code in C/C++/Python?

For these functions: SetHOM() Set a Hotine Oblique Mercator projection using azimuth angle. SetHOM2PNO() Set a Hotine Oblique Mercator projection using two points on projection centerline. SetHOMAC() ...
Mario Rossi's user avatar
0 votes
0 answers
36 views

Converting latLng to screen point

I have a map in RN app on iOS and I have and overlay outside of the map Inside overlay I need to draw a View with some absolute position that will match some LatLng coords on the map I know screen ...
Sedoyjan's user avatar
-2 votes
1 answer
219 views

Make very detailed SVG map of world country borders and administrative objects

I need very detailed map for my project, in Mercator projection. I tried to find downloadable resources, even not free, but all that I have found is in very bad resolution. I need as much detailed ...
Achat333's user avatar
0 votes
0 answers
42 views

Transform coordinates to WMTS tiles in EPSG:4362 [duplicate]

How can I calculate the tiles numbers/names in EPSG:4362 based on lat, lon and zoom ? Note that I was able to do it for EPSG:3857 Pseudo-Mercator, but the formula in wikipedia and the one in here ...
Philip St's user avatar
1 vote
0 answers
57 views

Map projection from latitude/longitude to cylindrical system [closed]

I have some questions about projections. First of all, I would like to plot some positions on a x-y grid, graduated in km from latitude/longitudes coordinates. Is this conversion relevant: https://en....
Tug Speedman's user avatar
1 vote
3 answers
429 views

Identifying the EPSG code for projection

I'm trying to convert a dataset that has projection parameters in meters to lat/long coordinates. After researching online and on stack exchange, I came up with a code. I used the input EPSG as 3857 ...
Rishikesh Sreehari's user avatar
0 votes
1 answer
73 views

Why does the calculation for y-value (when converting from lat/long to a Mercator x,y) involve the width of the map?

I have been looking into converting latitude and longitude into x and y coordinates. This link (first answer) provides a perfect answer for me, but I am wondering why it works. I have figured out why ...
Mercator3383279's user avatar
2 votes
1 answer
98 views

Create true length scalebar for different latitudes with QGIS geometry generator in Mercator projection

In Mercator projection, distances are heavily distorted, the closer you get to the poles. True distances can only be measured only on the equator. The distortion is constant along parallels - so e.g. ...
Babel's user avatar
  • 71.3k
3 votes
2 answers
759 views

How Mercator projection works

I found this web page that explains how Mercator projection works : https://personal.math.ubc.ca/~israel/m103/mercator/mercator.html In the section "How to do it", I didn't understand this ...
Aminos's user avatar
  • 133
9 votes
2 answers
4k views

Order of latitude and longitude in EPSG:4326

I recently started working with GPS data in PostGIS and am very confused about the order of latitude and longitude. I'm from Europe, and here everyone I know uses latitude first, longitude second, e.g....
Klamann's user avatar
  • 221
4 votes
1 answer
592 views

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 ...
Bad_deepLearner's user avatar
2 votes
1 answer
2k 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:...
Hannes's user avatar
  • 21
1 vote
0 answers
325 views

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 ...
mbk_wass's user avatar
1 vote
0 answers
206 views

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 ...
Jun_cant_draw's user avatar
2 votes
0 answers
345 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 ...
Sun's user avatar
  • 113
3 votes
0 answers
498 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 (...
map_maker_2001's user avatar
-1 votes
1 answer
851 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 ...
Shanzid Shaiham's user avatar
1 vote
0 answers
214 views

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 ...
Web-GIS entrepreneur's user avatar
0 votes
0 answers
306 views

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 ...
Martin Perry's user avatar
1 vote
1 answer
887 views

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 ...
David Moles's user avatar
1 vote
0 answers
65 views

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): ...
Dragonsen's user avatar
1 vote
0 answers
73 views

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 ...
user3494047's user avatar
3 votes
1 answer
683 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 ...
tgordon18's user avatar
  • 131
1 vote
1 answer
2k views

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, ...
riccardolardi's user avatar
0 votes
2 answers
410 views

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 ...
Justas Brazauskas's user avatar
4 votes
1 answer
2k 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, ...
exsonic01's user avatar
  • 171
-1 votes
1 answer
222 views

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; ...
gorill's user avatar
  • 141
0 votes
1 answer
6k views

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 ...
Slava's user avatar
  • 103
4 votes
1 answer
2k views

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 ...
Suraj's user avatar
  • 619
1 vote
0 answers
619 views

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 ...
Mateen Ulhaq's user avatar
0 votes
0 answers
448 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 ...
DR01D's user avatar
  • 111
1 vote
1 answer
119 views

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 -...
Venres_13's user avatar
0 votes
0 answers
2k views

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....
Ninita's user avatar
  • 119
1 vote
1 answer
210 views

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){ ...
Martin Perry's user avatar
1 vote
0 answers
186 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\"]]," ...
marie paule Corre's user avatar
2 votes
2 answers
187 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 ...
M. Beausoleil's user avatar
0 votes
1 answer
67 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 ...
johnsankey's user avatar
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 ...
Learning stats by example's user avatar
0 votes
1 answer
4k 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, ...
George's user avatar
  • 339
1 vote
0 answers
429 views

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 ...
user965972's user avatar
0 votes
1 answer
569 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 ...
Plastic Rabbit's user avatar
3 votes
1 answer
556 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 ...
nrhode's user avatar
  • 171
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 ...
juh's user avatar
  • 51
20 votes
1 answer
4k views

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]...
John Smith's user avatar
3 votes
1 answer
3k 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),...
John Smith's user avatar
2 votes
0 answers
224 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 ...
user71298's user avatar
11 votes
2 answers
8k 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 ...
sema's user avatar
  • 445
2 votes
1 answer
544 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"]], ...
Anna Magdalena's user avatar
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 ...
Stefan's user avatar
  • 4,414
6 votes
1 answer
11k views

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 ...
FraserOfSmeg's user avatar