vismap 0.1.0

Tile maps rendered with Vispy

Vismap

Provides a Canvas for creating maps with Vispy. The canvas gets its tiles from a TileProvider. Several tile providers are bundled with this project; adding a tile provider simply requires knowing the URL at which to grab a tile, and providing the attribution text for the tiles.

Run the provided example to check out how interacting with the map works. The script is installed as vismap-example if you install vismap; so from your command line just run

vismap-example

Use the left and right arrow keys to change the tile provider.

What's the Point?

The idea is to be able to display real-time geographical data on top of a map–for example, radar data. This project provides the canvas which automatically fills the map based on the current zoom level, and also provides transforms, so you can actually view data on top of the map. The transforms are located in vismap/transforms.py.

Currently, two transforms are provided: MercatorTransform and RelativeMercatorTransform. Use the MercatorTransform when your data is naturally represented in longitude/latitude pairs. For example, the following will draw a line from Norman, OK to Oklahoma City, OK:

from vismap import Canvas, MercatorTransform
import vispy.scene.visuals as visuals
from vispy import app
import numpy as np

c = Canvas()
c.show()
line = visuals.Line(np.array([[-97.4395, 35.2226], [-97.5164, 35.4676]]),
                    parent=c.view.scene)
line.transform = MercatorTransform()  # the magic line!
app.run()

The RelativeMercatorTransform is for plotting data that is naturally expressed in units of length, but would be nice if it were centered somewhere geographically. The motivating use case is radar data: it makes sense to think of the data in meters, relative to a specific latitude and longitude.

When you are using these transforms, make sure you always remember to add the visual to the correct scene, otherwise the data will not show up and it will probably be confusing.