Questions tagged [mercator]
The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator in 1569.
72
questions
1
vote
1answer
21 views
Mapping equirectangular square slice inside cubemap
I'm trying to map a square slice of an equirectangular image inside a cubemap with 6 faces, without distortion.
The point is that I'm dealing with huge array sizes if I try to project the whole ...
1
vote
0answers
41 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):
...
1
vote
0answers
49 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 ...
1
vote
0answers
38 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 ...
0
votes
0answers
30 views
GPS coord to SVG coords
I am trying to make an interrative map using SVG and I need to implement a coordinates system. So I look at http://jsfiddle.net/an3BZ/145/ but I do not know how did he calculated those nortLat ,...
0
votes
1answer
53 views
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 ...
1
vote
1answer
334 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, ...
0
votes
2answers
107 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 ...
3
votes
1answer
573 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, ...
0
votes
1answer
81 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; ...
0
votes
1answer
1k 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 ...
2
votes
1answer
428 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 ...
1
vote
0answers
317 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 ...
0
votes
0answers
240 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 ...
1
vote
1answer
50 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 -...
0
votes
0answers
980 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....
1
vote
1answer
130 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){
...
1
vote
0answers
110 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
2answers
127 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 ...
0
votes
1answer
55 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 ...
4
votes
1answer
860 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
1answer
2k 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, ...
1
vote
0answers
238 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 ...
0
votes
1answer
335 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 ...
3
votes
1answer
326 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 ...
4
votes
2answers
2k 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 ...
18
votes
1answer
2k 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]...
3
votes
1answer
1k 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),...
2
votes
0answers
158 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 ...
6
votes
2answers
3k 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 ...
2
votes
1answer
302 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"]], ...
3
votes
1answer
1k 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 ...
5
votes
1answer
2k 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 ...
1
vote
1answer
865 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 ...
2
votes
1answer
839 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 ...
2
votes
1answer
4k 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 ...
1
vote
0answers
627 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 ...
1
vote
0answers
287 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 ...
1
vote
1answer
7k 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 ...
4
votes
1answer
417 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 ...
3
votes
3answers
4k 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, ...
10
votes
3answers
18k views
Adding additional geometry column in PostGIS?
I'm importing many sets of geodata into PostGIS, and they have different SRID's. (Some have EPSG:3857, some EPSG:4326, some something else).
I'd like to create an additional geometry column, eg. ...
2
votes
1answer
657 views
Overlay a raster image using Equirectangular projection (lat/lon) onto OSM/Google map with openlayers?
I have a forecast map of 6x6 lat/lon extend from 104E-110E, 10N-16N as an static PNG image and want to make it an overlay on the basemap of OSM/Google map using openlayers 3. The problem is OSM uses ...
11
votes
3answers
3k views
How did sailors navigate before the Mercator projection (1536)? [closed]
The Mercator projection (1536) must be great for nautical navigation. It allows one to find a bearing and keeping this constant one should reach the target (if not in the shortest line). But how did ...
0
votes
1answer
615 views
Convert from WGS84 to 2D projection
I have a map in the form of .bil & .hdr using WGS84. I'd like to convert this into another map using a 2D projection while keeping the lat/long information. What I'd really like with this new map ...
1
vote
1answer
555 views
Fixing mercator coordinates that are outside the world bounding box?
I'm using mercator-projected overlays from a crowdsourced website where volunteers georectify images of maps by hand. Unfortunately, the slippy map that serves as the site's interface wraps and allows ...
1
vote
1answer
81 views
gdaldem hillshade stop working with new projection?
Parallel to gdalwarp `-te -5.8 41 10 51.5 -ts 1980 0` not working with mercator? , my hillshade works with lat/long input :
gdaldem hillshade input.tmp.tif shadedrelief.tmp.tif -s 111120 -z 5 -az ...
3
votes
1answer
730 views
Which projections emphasise the Northern Hemisphere, other than Mercator?
I'm working on a project where I have data points in the UK, US, France/Italy, Hong Kong and Japan. I want to show a world map with mini charts at each of these locations.
For this project, it makes ...
0
votes
1answer
210 views
Extent from Centroids, Projection, and Resolution?
I have a file that defines a raster, although all the metadata was lost. I know the lat/long coordinates of the grid centroids, and that the grid is in a Mercator projection with a 1/12deg equatorial ...
0
votes
0answers
181 views
Reprojecting xy tiles from mercator to Gauß-Krueger in ubuntu terminal?
I have exported a map from tilemill as mbtiles and converted them to xyz tiles with help of mbutil. The tiles should be used (for learning purpose) with mod_tile or GeoServer and displayed in ...
