This week covered different ways to asses the accuracy of a DEM. LiDar data was compared to survey points.
Thursday, December 14, 2017
This lab was a review of statistics. I estimated the rainfall at weather station A for years with missing data based on data from weather station B. Below is the chart.
Tuesday, November 21, 2017
Three types of interpolation were covered which are Thiessen, IDW, and Spline. Water quality data was used to illustrate the different methods. Each of these methods resulted in different statistical results. Below is the IDW results.
Saturday, November 11, 2017
This week we created and compared TIN and DEM elevation models. TIN are vector based and use points and edges to create a triangle network and DEM are raster. Below is an image of a TIN with contours, nodes, edges and elevation visible.
TINs are more accurate but generally need to be created for the project. DEMs are more available and often take less time to process.
Saturday, October 28, 2017
This week covered routing multiple vehicles, such as a delivery fleet. For this lab, I used ArcGIS Vehicle Routing to make delivery routes for multiple trucks with specific delivery times. Below is the final result. The first result left out several orders and some deliveries were the expected time window. Adding two more trucks solved this and improved customer satisfaction.
Monday, September 25, 2017
This week we compared the completeness of two road networks, TIGER and Street Centerline in Jackson County, OR.
I used the intersect tool on both sets of street data against the grid shapefile. I joined both results to the grid shapefile and created a new column to calculate the difference in length between each street set for each grid. Below is a map of the results.
Saturday, September 23, 2017
This week covered determining the positional accuracy of road networks using intersections and comparing the intersection to a orthophoto. The distance between the point and where it was located in the orthophoto was put in formulas in excel to determine the accuracy. Below is the sample points that I used.
Using the National Standard for Spatial Data Accuracy, the data set tested 12.3 feet horizontal accuracy at 95% confidence level.