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Questions tagged [map-projections]

A map-projection transforms the coordinates of the spherical earth to a flat map in cartesian (x,y) space.

A map-projection transforms the coordinates of the spherical earth, usually given in degrees (latitude, longitude), to a flat cartesian (x,y) space.
There is no perfect projection, it can be proved that each projection has a drawback, one have minor others major ones.

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How can I find out what projection my pre-projected GeoJSON is using?

My question is very similar to D3 V4 Properly placing a bubble in the US Map, but the map I'm using is a map of Scotland's local authority districts instead so I can't quite see how to apply either of the solutions. I'm creating a bubble map on top…
squirrel
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Reprojecting geotiff data and plotting with Python

I have a geotiff and a data array with the same shapes. The data array is auxiliary data of the geotiff. The x and y coordinates are the size of the geotiff coordinates, but the data array has no projection. I am trying to project the dataarray with…
user1643523
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Geopandas to_crs gives wrong coordinates after transformation

I am trying to plot a shapefile as points a Folium map but am pulling my hair out trying to get the projection correct. The data is in the EPSG:28992 system, the RD new coordinate system. This is a projected coordinate system, thus it gives…
jcnc
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D3 Robinson projection gives curves latitude lines

I have some javascript using d3 that can draw a map using a robinson projection, and I can even draw a simple box atop the map using my projection to build a path generator. However, the box I get out is curved along its horizontal lines: I thought…
whiterook6
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How do I plot data lines on a map in Matlab correctly while setting the map limits

I have some data (latitude, longitude) data (sorry for the long data, I can't seem to replicate the problem with other artificial data): data1lat = [40.47 40.4697 40.4692 40.4686 40.4682 40.4681 40.4679 40.4673 40.4667 40.4663 40.4662 40.4662…
Sam
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Openlayers geometry how to calculate area from square degrees to square kilometres?

I get the multypoligon from webservice and I try to calculate area for that poligon with the following code: var poly = new OpenLayers.Geometry.MultiPolygon(poligon); var area = geom.getArea(); But that returns me area in square degrees, our…
vaske
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How to calculate the x,y-tile-coordinates from lat,long if given images in EPSG25832-projection method?

I have a question regarding the creation of the WMTS server requests and with that the calculation of the tile number. From this german governmental-website I can get the address for their WMTS server: https://www.wmts.nrw.de/geobasis/wmts_nw_dop. I…
autonomobil
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What does the google.maps.Projection class do?

Recently I found out the hard way that to convert between LatLngs and pixel coordinates on screen I shouldn't use the Projection class that is easily accessed through Map.getProjection, but instead I should use the MapCanvasProjection class that can…
Rene Saarsoo
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Limiting latitudinal extend of a cartopy orthographic projection

I am trying to plot a map of a sphere with an orthographic projection of the Northern (0-40N) and Southern (0-40S) hemispheres, and a Mollweide projection of the central latitudes (60N-60S). I get the following plot: which shows a problem: there is…
Adriaan
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Projecting a set of lat/lon points that spans on multiple UTM zones into a single grid

I'm working on a project where I need to transpose a lot of geographic locations (given by their latitude/longitude), all of them in a relatively small region (the size of a country like Nederlands for instance), into a grid in order to run some…
m.raynal
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Why does pyproj.Proj forward projection not seem to account for lat lon origin?

I am getting confused about how projections using pyproj.Proj are defined with respect to a point of tangency / lat lon origin. Consider the following code: import pyproj p = pyproj.Proj('+proj=tmerc +lat_0=55 +lon_0=-1 +a=6378137 +b=6356752.3…
Liam Deacon
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Managing projections when plotting in Geopandas

I am using geopandas to draw a map of Italy. import matplotlib.pyplot as plt fig, ax = plt.subplots(figsize = (20,30)) region_map.plot(ax=ax, color='white',…
ale-6
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Error changing projection via coord_sf for geom_sf and geom_point at the same time

I want to plot a map with geom_sf and add points from another dataset, then change the projection. For example: # setup library(ggplot2) library(sf) nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE) point <- data.frame(id…
twedl
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D3 cartography: lon/lat circles in wrong place on map (projection)

I have a question about D3 cartography. I am working on a little project and I am new to D3. I have started out from this example: http://bl.ocks.org/mbostock/5914438 Instead of the showing the state-mesh, I would like to show circles on the map in…
user10575146
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Miller Projection to pixels

I'm trying to use Miller Projection to convert coordinates to pixels. My method looks like this: function millerProjection(lat, lng) { // Create sec() function // function sec(value) { return 1/Math.cos(value); …
Ben
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