A library, and command line tools, to play with geographic data.
This project is still experimental.
This project use
Theses dependencies are include in the projet as git submodules. So, use the following command to clone the repository, and have all the needed code :
$ git clone --recurse-submodules https://github.com/thaddeus002/cartograph.gitBLN file format is a simple text format to represent curves (countries' boundaries, coast, roads, rivers, ...) as a succesion of points. Drawing lines between the points make the curve's trace. One or more curves can be present in one file. A curve is one header on a file line containing the number (n) of points, and optionnaly the name of the curve separate from n by a comma. The header is followed by n lines containing the points coordinates separated by commas. The coordinates may be (X,Y) for Lambert projection, or more often (lon, lat).
For example, the file world.bln contains world's countries ' boundaries with a pretty good resolution.
The program trace can make a map from bln data. It's built by the command :
$ make -C src traceThen we can use it to create a graphic representation of the data of file world.bln, and also plot some cities from file cities.csv.
This map was made by the command :
$ src/trace data/world.bln data/cities.csvThe first argument is the filename for bln data and the second, which is optional, is the name of a csv file containing points to plot on the map.
For this example, data layer is provide as a png image by a WMS server. The temperatures are placed on an image with a black background.
To localize the data we need a background image with at least countries boundaries. We have this boundaries in file europe.bln.
data source : Météo France
geoservices' documentation (in french)
The raw image is :
The program output shows the same data with a better background :
