projections
Collection of (stereographic) map projections. See this Wikipedia list.
Installation
npm install --save projections
Usage
const projections = // for all projectionsconst mercator = // for a specific projection
WGS to map coordinates
const x y = // x ≊ 0.53722// y ≊ 0.32686
Given an object containing lon
and lat
, mercator
returns an object {x: …, y: …}
(0 ≤ x ≤ 1
). For details on the range of y
, see the map height column in the projections table.
Map coordinates to WGS
const lon lat = // lon ≊ 13.5// lat ≊ 52.4
Given an object containing x
and y
(0 ≤ x ≤ 1
), mercator
returns an object {lon: …, lat: …}
.
Be sure to use the same options everytime you're converting coordinates back and forth to get correct results.
Projections
Projection | Full name | Available options | Map height* |
---|---|---|---|
braun |
Braun stereographic | meridian , latLimit |
|
central-cylindrical |
Central cylindrical | meridian , latLimit |
|
equirectangular |
Equirectangular | meridian , standardParallel |
1 / 2 |
gall |
Gall stereographic | meridian , latLimit |
|
gall-peters |
Gall–Peters | meridian |
2 / π |
kavrayskiy-7 |
Kavrayskiy VII | meridian |
1 / √3 |
lambert |
Lambert cylindrical equal-area | meridian |
1 / π |
mercator |
Mercator (Web) | meridian , latLimit |
|
miller |
Miller cylindrical | meridian , latLimit |
|
sinusoidal |
Sinusoidal | meridian |
1 / 2 |
wagner-6 |
Wagner VI | meridian |
1 / 2 |
* If the projection uses a latitude limit, the map height is the value of y
at {lon: meridian, lat: -latLimit}
. Otherwise it is the value of y
at {lon: meridian, lat: -90}
.
Options
Option | description | Default |
---|---|---|
meridian |
Latitude of the central meridian | 0 |
latLimit |
maximum latitude in degrees < 90 | 85 |
standardParallel |
longitude of the standard parallel(s) | 0 |
Contributing
If you found a bug, want to propose a feature or feel the urge to complain about your life, feel free to visit the issues page.