## A rational for your design decisions
#### Encoding Thoughts:
My project consist of three-part. A line chart, a bar graph, and a map. The purpose of the project is to illustrate the incarceration.
the rate in each state from 1978-2014. I choose the bar graph to demonstrate the top 10 states in incarnation rates. I also order a bar graph 
in order. The reason why I choose the bar graph is that bar graph is the most effective way to demonstrate quantitative data.
In our previous class, we teach that quantitative date should use Position, length,angle, slope to demonstrate data.
I also consider using a bubble map, which uses area encoding. Though it looks good, it doesn't express what we want effectively.
Secondly, In my line graph, It could tell the change of incarceration rate over the years. No other encoding can fulfill this goal effectively.
The alternative design is points,Points is not a good encoding in this case Since I do not want to find the relationship between my 2
data. I also use areas encoding, such as a USA map. One alternative design is mapping points on my map, 
but it is not a good use in my case. My data refers to larger areas such as states. Thus, mapping points is bad in this case, 
So I have to map state to colors. It could easily show which state in current year has most incarnation rate.

#### Interaction techniques Thoughts:
In my project, I use dynamic queries to select data in a year. I also have zoom ability in the map and hover ability in the map. 
So users could hover to each state and find out corresponding information. Also When I hover in the state in the map, my line graph will be changed correspondingly.
When I choose a different year, my bar graph will automatically display the top 10 states. When I hover on each bar  I can see the
the difference in data between this state and the other 9 states.
I think about brushing techniques. However, My current data do not have many fields need to demonstrate. That is why I do not consider that option. 
Besides, I also think about the filter, sort interaction. These are good techniques that I could use in my project.
For example, Users could sort state based on overall years. Right now I only display the top 10 states each year. I could let the user 
sort all states and display them if the user wants. The reason why I do not include this technique is that my main goal for this project
is to display incarceration rate over the years. I am only interested in the top ten states. One more reason is that my dataset limitation. 
I do not have a dataset for  incarcenation  such as gender, race, and data in each of the cities. 

## An overview of your development process
1. pick my topic, I pick this topic is because my previous gened class talk about this and I am interested to find outthe incarcenation in each state in each year.
2. I look my lecture notes and desicide what kind of encoding I should use. What kind of graph i should draw.
3. look interaction techniques lecture and decide what kind of interaction techniques I should use.
4. get data and start coding!
5. Make it beautiful 
6. Fix bugs

I roughly spent one week to finish the project. It spent roughly 20 hours. I forget how to use d3.js. So I have to read through lecture code and A2.
The most difficult part is to add interaction technique in the project. For example, I spent 3-4 hour to figure out how to add zoom in and out ability in map.
Another time consuming part is UI part. I am not sufficient at css, so it is kind difficult for me to make it pretty.