Activity 1: DIgital Scanning

For this activity we "digitized" a hand-drawn plot by scanning it and then tabulating the corresponding xy values of the pixels of the points of the plot. To replicate the actual data, we had to figure out the relationship between the actual physical values and the pixel data we've gathered. To do this I measured the pixel distances between grid lines and divided them by their corresponding physical values. I found that the ratio was unconsistent and I ended up with varying ratios per area of the chart. Upon replotting the data, I dealt with this simply by using the different ratios for different points depending on their locations. I came up with the following plot:

The reconstruction was accurate for the first three points, but as the plot progressed, the digitized points (in red) start to deviate from the actual plot. Furthermore, the x=-50 and x=50 grid lines don't seem to match up. While the y deviation simply increses (the digitized points deviate downward) as the plot moves forward, the x deviation increases at the middle of the plot but recovers towards the end. The most probable reason for the error I obtained is that I failed to rotate the image before obtaining the pixel data and so when I was forced to rotate the image later on when overlaying the original, The points matched up only at certain points (probably those that were near the axis of rotation).

For this reason I can only give myself a grade of 7. I was able to follow the procedure for the most part, but a crucial error at the start of my data gathering doomed the final result.