Geographic Data with Basemap

Geographic Data with Basemap

• Basemap is a toolkit under the Python visualization library Matplotlib. Its main function is to draw 2D maps, which are important for visualizing spatial data. Basemap itself does not do any plotting, but provides the ability to transform coordinates into one of 25 different map projections.

• Matplotlib can also be used to plot contours, images, vectors, lines or points in transformed coordinates. Basemap includes the GSSH coastline dataset, as well as datasets from GMT for rivers, states and national boundaries.

• These datasets can be used to plot coastlines, rivers and political boundaries on a map at several different resolutions. Basemap uses the Geometry Engine-Open Source (GEOS) library at the bottom to clip coastline and boundary features to the desired map projection area. In addition, basemap provides the ability to read shapefiles.

• Basemap cannot be installed using pip install basemap. If Anaconda is installed, you can install basemap using canda install basemap.

• Example objects in basemap:

a) contour(): Draw contour lines.

b) contourf(): Draw filled contours.

c) imshow(): Draw an image.

d) pcolor(): Draw a pseudocolor plot.

e) pcolormesh(): Draw a pseudocolor plot (faster version for regular meshes).

f) plot(): Draw lines and/or markers.

g) scatter(): Draw points with markers.

h) quiver(): Draw vectors.(draw vector map, 3D is surface map)

i) barbs(): Draw wind barbs (draw wind plume map)

j) drawgreatcircle(): Draw a great circle (draws a great circle route)

• For example, if we wanted to show all the different types of endangered plants within a region, we would use a base map showing roads, provincial and state boundaries, waterways and elevation. Onto this base map, we could add layers that show the location of different categories of endangered plants. One added layer could be trees, another layer could be mosses and lichens, another layer could be grasses.

Basemap basic usage:

import warnings

warnings.filterwarmings('ignore')

frommpl_toolkits.basemap import Basemap

importmatplotlib.pyplot as plt

map = Basemap()

map.drawcoastlines()

# plt.show()

plt.savefig('test.png')

Output: