I'd like to map some sensor values, what should I use?

Hi, I'd like to make a 2D map of some sensor values I will measure with my robot, such as light intensity. What mapping tool should I use? I'm a little bit confused between gmapping, costmap or even if I should be using any of these! I'd like to colour code so that high light intensity gets a different colour in the map than dark and some gradual changes in between. Thank you