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// See https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames for more details. | |
var degrees2meters = function(lon,lat) { | |
var x = lon * 20037508.34 / 180; | |
var y = Math.log(Math.tan((90 + lat) * Math.PI / 360)) / (Math.PI / 180); | |
y = y * 20037508.34 / 180; | |
return [x, y] | |
} | |
x= -77.035974 | |
y = 38.898717 | |
console.log(degrees2meters(x,y)) | |
// should result in: -8575605.398444, 4707174.018280 |
how to convert from projection to lon/lat ?
are there ways to convert a geojson 3857 coords to 4326?
doing it with r and java but cant find a way that would solve the propblem
epsg.io is perfect for single data,
function trans2(){
var test_x = document.getElementById("test_x").value;
var test_y = document.getElementById("test_y").value;
var ll2=new OpenLayers.LonLat(test_x, test_y).transform(
new OpenLayers.Projection("EPSG:900913"),
new OpenLayers.Projection("EPSG:4326")
);
$("#test_ll_x").val(ll2.lon);
$("#test_ll_y").val(ll2.lat);
}
is cool for java
but would like to know ways to do it in R
Here's my general workflow for transforming a CRS in R.
With some GIS file (shp, gpkg, etc):
library(sf)
library(dplyr)
filepath <- system.file("shape/nc.shp", package="sf")
st_read(filepath) %>%
st_set_crs(4326) %>%
st_transform(3857)
With a CSV:
df <- read.csv("some_csv.csv")
df %>%
st_as_sf(coords = c("lat_col", "lng_col")) %>%
st_set_crs(4326) %>%
st_transform(3857)
Thank you so much! It was really helpful.
console.log(degrees2meters(-180,-90)) // [-20037508.34, -Infinity]
Can you please help with converting meters to lat long?
The C++ macro posted above works well for converting meters to lat/long degrees: #define DEGREE_TO_METER_REVERSE(Y) (atan(pow(M_E, ((Y)/111319.490778)*M_PI/180.0))*360.0/M_PI-90.0)
(Thanks @jiangfeng79!)
Should be trivial to adapt to Python.
@marzochi
You may still find the way to convert EPSG:3857 to EPSG:4326, this gonna help you.
https://epsg.io/transform#s_srs=3857&t_srs=4326