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https://github.com/jorelosorio/web-mercator-projection

A Go project to explore the math to calculate and present data in a map using the `Web Mercator Projection`
https://github.com/jorelosorio/web-mercator-projection

geolocation geospatial golang golang-library google-mercator-projection image-processing imagemagick map maps openstreetmap web-mercator

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A Go project to explore the math to calculate and present data in a map using the `Web Mercator Projection`

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# Web Mercator Projection



[![Tests](https://github.com/jorelosorio/web-mercator-projection/actions/workflows/tests.yml/badge.svg)](https://github.com/jorelosorio/web-mercator-projection/actions/workflows/tests.yml)

[![Go Report Card](https://goreportcard.com/badge/github.com/jorelosorio/web-mercator-projection)](https://goreportcard.com/report/github.com/jorelosorio/web-mercator-projection)

[![Coverage Status](https://coveralls.io/repos/github/jorelosorio/web-mercator-projection/badge.svg?branch=main)](https://coveralls.io/github/jorelosorio/web-mercator-projection?branch=main)

[![Go Reference](https://pkg.go.dev/badge/github.com/jorelosorio/web-mercator-projection.svg)](https://pkg.go.dev/github.com/jorelosorio/web-mercator-projection)



![WorldMap](https://github.com/jorelosorio/web-mercator-projection/blob/main/assets/cover.png?raw=true)



A Go project to explore the `Math` to calculate and present data in a map using the `Web Mercator Projection`.



> To get more information about this topic, please look at the following references: 



- https://en.wikipedia.org/wiki/Web_Mercator_projection

- https://www.maptiler.com/google-maps-coordinates-tile-bounds-projection/#3/15.00/50.00

- https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames



## How does this project work?



In the main example project, there is a file `main.go` that contains the following actions available:



- Convert a `LonLat` into a `Point` coordinates and vice versa.



- A function to add a `Red-Marker` into a map image. (The coordinates must be setted manually in the code)

    > The resultant image will be stored in a folder named `data`.



This is how the `main.go` will print out the information:



    LonLat: {-74.92010258781309 11.045882360336755}

    Point: {298.8939304168872 480.38414652354516 2}

    Tile: {1 1 2}

    LonLat from Point: {-74.9201025878131 11.045882360336744}



### Structs definitions



- `LonLat`: A location in the map using angles in degrees.

- `Point`: A pixel in the map for a specific zoom or scale.

- `Tile`: Represent at which (tile/block) a Point or LonLat is.



> If you are curious about how the maps where built using the data in `OpenStreetMap` please take a look at this `Gist` https://gist.github.com/jorelosorio/7042bd27e4b2bb03865215d6a5607266



## Tools



- GoLang `1.17`

- Docker

- ImageMagick `6.9.11-60`

- Visual Studio Code `Optional!`

    > It requires a `Remote - Containers` extension. for more information please refers to: https://code.visualstudio.com/docs/remote/containers#_getting-started



## Development



This project contains a `Dockerfile` file with all required dependencies to run it using `Visual Studio Code` + `Remote - Containers` extension.

However, if you want to make it run locally in your development machine, please follow the instructions below.



### Install Go



Install it from https://go.dev/dl/



### Install ImageMagick



Install it using the following instructions https://imagemagick.org/script/download.php



### Build the executable



    go build ./examples/main.go



> The binary file depends on the `assets` folder to build the map, make sure to have it on the same directory.



## Licences and assets



- `OpenStreetMap` data is licenced under the Open Data Commons Open Database Licence (ODbL). https://opendatacommons.org/licenses/odbl/1-0/



- `Red marker icon` https://www.iconfinder.com/icons/299087/marker_map_icon Creative Commons (Attribution 3.0 Unported) http://creativecommons.org/licenses/by/3.0/