Displaying spatial data on maps is always interesting but most Visualisation tools do not offer facilities to create maps of India, especially at the state and lower levels. In this post, we will show how such maps can be made.
The base data for such maps, the "polygons" that define the country, the states, the districts and even the talukas ( or sub-divisions) is available from an organisation called Global Administrative Areas or gadm.org. Country level files for almost all countries are available in a variety of formats including R and these are at three different levels. For India, these files can be downloaded as IND_admN.RData where R = 1,2,3. These will form the raw data from which we will create our maps.
Now let us get a map of the district - North 24 Parganas. Make sure that the name is spelt correctly.
# get map for "North 24 Parganas District"
This is the highest resolution ( or lowest administrative division ) that we can go with data from gadm. However even within a map, one "zoom" into and enlarge an area by specifying the latitude and longitudes of a zoom box as shown here.
With this it should be possible to draw any map of India. For more comprehensive examples of such maps, please see this page.
new PostScript : The full code for creating this maps as well as additional information on how to place text and markers on these maps is available on my specialist visualisation blog.