Is there an algorithm for compressing floats and numbers in JSON?

As far as I know JSON sent over HTTP REQUESTs are send as pure strings and are not bit encoded for different types.

As I'm developing a mapping application which will retrieve huge json data to represent thousands of coordinate points I would like to shrink JSONs before POSTing and GETing.

I want to know if there is any encoder/decoder algorithm to perform some kind of minify to convert for example a float 1.2016481243784631812 into some shrinked hexadecimal or even a larger base representation since JSON will accept any character?