Questions tagged [mercator]
The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator in 1569.
91 questions
0
votes
1
answer
31
views
Discrepancies in EPSG:3857 Spherical/Web Mercator World bounds
This Question Spherical Mercator - World bounds
is answered by this Answer,
which cites https://epsg.io/3857 with the following bounds:
xmin: -20037508.3427892,
ymin: -20037508.3427892,
xmax: 20037508....
0
votes
0
answers
45
views
Mercator CRS that covers the extent -90,-180 to 90,180
Is there a EPSG CRS for Mercator that isn't deprecated and covers -90.0,-180.0 to 90.0,180.0?
- 113
0
votes
1
answer
64
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()
...
- 43
0
votes
0
answers
59
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 ...
- 1
-2
votes
1
answer
525
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 ...
- 1
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 ...
- 21
1
vote
0
answers
80
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....
- 11
1
vote
3
answers
531
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 ...
0
votes
1
answer
97
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 ...
2
votes
1
answer
113
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. ...
- 74.9k
3
votes
2
answers
795
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 ...
- 133
10
votes
2
answers
6k
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....
- 231
4
votes
1
answer
685
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 ...
2
votes
1
answer
3k
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:...
- 21
1
vote
0
answers
338
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 ...
- 19
1
vote
0
answers
246
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 ...
2
votes
0
answers
386
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 ...
- 113
3
votes
0
answers
527
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 (...
-1
votes
1
answer
1k
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 ...
1
vote
0
answers
253
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 ...
- 1,575
0
votes
0
answers
377
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 ...
- 491
1
vote
1
answer
962
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 ...
- 113
1
vote
0
answers
67
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):
...
- 11
1
vote
0
answers
74
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 ...
- 111
3
votes
1
answer
789
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 ...
- 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, ...
- 111
0
votes
2
answers
461
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 ...
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, ...
- 171
-1
votes
1
answer
245
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; ...
- 141
0
votes
1
answer
7k
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 ...
- 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 ...
- 629
1
vote
0
answers
663
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 ...
- 111
0
votes
0
answers
458
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 ...
- 111
1
vote
1
answer
130
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 -...
- 11
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....
- 119
1
vote
1
answer
222
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){
...
- 491
1
vote
0
answers
205
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\"]],"
...
2
votes
2
answers
193
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 ...
- 291
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 ...
- 573
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 ...
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, ...
- 339
1
vote
0
answers
460
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 ...
- 111
0
votes
1
answer
605
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 ...
- 121
3
votes
1
answer
603
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 ...
- 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 ...
- 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]...
- 389
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),...
- 389
2
votes
0
answers
243
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 ...
- 29
11
votes
2
answers
9k
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 ...
- 445
2
votes
1
answer
566
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"]], ...
- 179