Mapping Earthquake in Bohol using R

On my previous post a year ago (on mapping earthquake recorded for the Philippines), it can be seen that there were no earthquake (epicenter) recorded for the province of Bohol. But on the 15th of October there were more than 40 quakes recorded that hit the island from early in the morning till late midnight with magnitude ranging from 2.7 to 7.2.

Below is the map, created using R, of earthquakes that hit the province:

Overlapping Histogram in R

While preparing a class exercise involving the use of overlaying of histogram, I searched Google on possible article or discussion on the said topic. Luckily, I found a blog where the author demonstrated an R function to create an overlapping histogram. However, a comment from a guy also showed the same output using transparency. Below were the sample codes that can be used to generate overlapping histogram in R as based on the blog and the viewers comment.

                                                                                                                                     

                                                                                                                        

Here are the codes: