The jsroute sub-project allows us to use Google Maps from the command
line. To do this, we require the env-js Javascript library. A remote
reference, called a "submodule,"[1] has been created in the
census-tools repository and points to env-js. To initialize/update it,
run,

  git submodule init
  git submodule update

Those two commands will initialize the submodule, and check it out
within the lib/env-js directory. Now that env-js is present, you'll
need to build it. There are some prerequisites for this; in
particular, a Java runtime[2] and the Ant[3] build tool. If you are
running Linux, I promise that both of these are available through your
package manager.

With the prerequisites installed, simply run 'make env-js' from within
the 'lib' directory. This will change into the env-js directory, and
run 'ant concat' which builds the library. With that complete, you can
use jsroute.

Just run ./jsroute from within this directory to display its usage.


[1] http://book.git-scm.com/5_submodules.html
[2] http://java.com/en/download/index.jsp
[3] http://ant.apache.org/