Special Topics Mod 1.1

 

Special Topics Mod 1.1

In this module we were tasked with analyzing spatial data points that were collected during a survey. 

In the first portion or "Part A" we looked at a point file of way points with an averaged way point after. 

We wanted to learn the distance between all of the way point to the average waypoint so we used the spatial join tool, and then performed data analysis in excel to use for a multiple ring buffer. 

The three buffers represented the 50th, 68th, and 95th percentiles of points as it relates to their distance to the average way point. 

My results for horizontal accuracy and precision are reflected below and the information for the values is found in the legend. 

50% of the points were located within 2.9 meters of the Average point. 

68% of the points were located within 6.5 meters of the Average point. 

95% of the points were located within 16.8 meters of the Average point. 

Below is the layout for Part A

For Part B of the module we analyzed the amount of error in accuracy and precision for another file. 

We exported the file to excel and added categories for Benchmarks, error and RMSE along with median, percentiles and mean. 

Much of what we were determining in this file were averages between long lists of data; primarily X-coordinate and Y-coordinate. 

Lastly I'd like to briefly describe the difference between how horizontal accuracy and precision is determined and what those terms mean. 

Horizontal Precision is exactness or preciseness of a group of data, If I have known location or reference point, the precision of the tool that I'm using to replicate its location with my equipment may not be accurate as it relates to the true location of the reference point, e.g. I took ten points on the same reference point but all of the points are bunched together 1 meter away north east of the actual true point. 

Horizontal Accuracy is a different value as if I collected 10 survey points on a true location point or "Control point" and all ten points were very close to the point but spread out within 0.50 meters from the true point, that would be considered high accuracy.