Stack Overflow
Stack Overflow

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.

448 questions
5
votes
1 answer

Latitude/longtitude conversion to image x/y coordinates (Miller Cylindrical projection)

As already said in the title, I need some help with converting lat/long to x/y coords in Miller Cylindrical projection. I`m currently writing an app (in Java) which gets city list as an input and then gets lat/long for each city from Yahoo…
Varnius
  • 1,527
  • 1
  • 12
  • 14
5
votes
4 answers

matplotlib.mlab.griddata very slow and returns array of nan when valid data is input

I am trying to map an irregularly gridded dataset (raw satellite data) with associated latitudes and longitudes to a regularly gridded set of latitudes and longitudes given by basemap.makegrid(). I am using matplotlib.mlab.griddata with…
Vorticity
  • 4,582
  • 4
  • 32
  • 49
5
votes
2 answers

Mapping of 2D Points to a new Perspective

This is my first post! I'm trying to make an application that can determine whether certain points in a grid (image) are light or dark. The original grid is well defined (I know where all the points should be relative to the corners). Once I know…
robmoran
  • 51
  • 3
5
votes
1 answer

Creating an ASCII art world map

I'd like to render an ASCII art world map given this GeoJSON file. My basic approach is to load the GeoJSON into Shapely, transform the points using pyproj to Mercator, and then do a hit test on the geometries for each character of my ASCII art…
rgov
  • 3,516
  • 1
  • 31
  • 51
5
votes
2 answers

Putting matplotlib hexbin into an Aitoff projection

I have the nice hexbin plot below, but I'm wondering if there is any way to get hexbin into an Aitoff projection? The salient code is: import numpy as np import math import matplotlib.pyplot as plt from astropy.io import ascii filename =…
npross
  • 1,756
  • 6
  • 19
  • 38
5
votes
2 answers

plotting a sf object with geom_sf() with any projection other than lat-long

I am trying to plot a polygon with geom_sf() in any projection other than lat-long. I am using the example found in the manual pages for geom_sf() Importing the dataset: nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet =…
ze miguel
  • 306
  • 3
  • 9
5
votes
6 answers

How can I get Proj4 details from the shapefile's .prj file?

I am using mapdotnet services for our gis application to load the shapefiles, and this mapdotnet service wants the proj4 details. I'm getting them from spatialreference.org, but for this projection the proj4 details are blank. How can I get the…
Tushar Maru
  • 3,347
  • 10
  • 34
  • 53
5
votes
3 answers

GDAL reprojection error: in method 'Geometry_Transform', argument 2 of type 'OSRCoordinateTransformationShadow *'

Using Python 2.7.9 with GDAL 1.11.1, with miniconda for package management -- Performing this a simple reprojection of a coordinate point causes the error described below. I am relatively new to GDAL, so I checked to see if the code from the Python…
Val H
  • 507
  • 4
  • 13
5
votes
5 answers

What projections in r will fatten a city map?

I'm trying to make some city maps, and I'd like to distort them a bit so that the densest parts (manhattan in this case) appear to be a little wider on the final map. I'm having a hard time finding good projection examples at the city-level. I'd…
Anthony Damico
  • 5,779
  • 7
  • 46
  • 77
5
votes
4 answers

How do make my plot points smooth in d3.js using projection?

I'm able to plot some weather data onto a map using the following code. However the points are rectangles and i'd like to get them smoother. , I'd like to plot them smoother like something similar to I believe I need to look into interpolating,…
user176855
  • 289
  • 1
  • 6
  • 17
5
votes
2 answers

d3.js : orthographic rotation optimization

I made a map using an orthographic projection and I try to improve performance because the rotation is not smooth (around 6-7FPS). It's a map of the world built with a topojson file (world-100m). I need to interact with country and colorized them so…
John Smith
  • 489
  • 1
  • 6
  • 12
5
votes
0 answers

Google Maps API v3: ImageMapType over aerial (tilt, oblique, 45 degree) imagery not lining up

I have an ImageMapType that gets displayed on top of Google's base maps. Everything lines up perfect, except when going into the 45 degree view (tilt, aerial, obliques). I've read that in v2, there is a GObliqueMercator class that might be useful.…
Rob
  • 156
  • 1
  • 10
4
votes
2 answers

d3 geo projection transitions from orthographic to X

I'm working on an educational map project in which different map projections are displayed. I'd like to implement a morph transition between choosing different projections. I've found a great example how to implement it, and I've had not much…
nirazul
  • 3,928
  • 4
  • 26
  • 46
4
votes
1 answer

Shader that transforms a mercator projection to equirectangular?

I am trying to make a shader in Unity taking a mercator projection texture as a source and converting it to an equirectangular projection texture. Input example: Output example: This example does the opposite with an equirectangular as…
bomanden
  • 314
  • 1
  • 2
  • 16
4
votes
1 answer

Looking for a world map with a specific projection in d3js

I have played around with the d3js (v5) maps, i'm trying to generate this map (the screenshot was taken from a random website), For my particular case there is no need to present Antarctica. I have read the documentation here:…
JammingThebBits
  • 732
  • 11
  • 31
1 2
3
…
29 30