Spatial Data Quality

-

 


This week we discussed how to measure spatial data quality. The map layout below includes GPS waypoints, the average GPS waypoint, and three buffers for varying horizontal precision. I calculated horizontal precision by first measuring the distance between the average waypoint and the other waypoints. Then I found the index value for each precision from which I could find the maximum value at that index. This value was the edge of the precision boundary. 

To calculate the accuracy of the dataset I inserted the true reference point. I then measured the distance from the true point to the average waypoint. The distance was 3.25 m. This was 1.21m less than the horizontal precision (68%) measurement. 

Below is the map layout, I have included the average measurements and the precision measurements.  

o Average longitude in decimal degrees

27.825849

o Average latitude in decimal degrees

-82.318883

o Horizontal precision (68%) in meters

4.466187 m

o Vertical precision (68%) in meters

29.4459 m

o Average elevation in meters

28.542222 m 


Comments

Post a Comment

Popular posts from this blog

GIS Programming- Exploring and Manipulating Data

-
Image
 This week we learned about exploring and manipulating data in ArcGIS Pro with Python scripting. We learned about a variety of tools and methods, such as describe, exist, listing, dictionaries, and cursors. In the assignment, we were given a variety of tasks. First, we were to create a new file geodatabase. Next, we were to list all of the feature classes in another folder. We then copied those feature classes into the new file geodatabase. Using one of the files in the new geodatabase, we used the search cursor to identify the objects that matched specific criteria and printed that information. Finally, we created a dictionary with this information.  I encountered issues with populating the empty dictionary. I was attempting to use the row.getvalue method,  I kept receiving the error that my tuple did contain the attribute. I began my troubleshooting by searching for various methods to update dictionaries. From there I edited small things in my script, such as the input ...
Read more

Spatial Data Quality Standards

-
Image
 This week we learned about the various data quality standards, specifically NMAS and NSSDA. In our exercise, we applied the NSSDA methodology to test the accuracy of two maps in Albuquerque, NM. The two maps are from the city of Albuquerque and StreetMaps USA. I used Minnesota Planning's Positional Accuracy Handbook as a reference(1999).  After downloading the provided data and before starting the analysis, I first created my excel spreadsheet based on the worksheet provided by the Positional Accuracy Handbook (Minnesota Planning, 1999). Next, I created a point feature class and selected my 20 sampling points, referenced in Figure 1. I made sure the points were properly distributed, with each quadrant having less than 20% of the points. They are all located at intersections.  Figure 1. 20 sampling points on the city of Albuquerque's map. I then created two more feature classes for the StreetMaps USA map and the reference points. I made sure that I went in the same order ...
Read more

A little bit about me..

-
Hi there! My name is Emily Talbert and I am currently working on my master's in Historical Archaeology at UWF. I received my bachelor's in Anthropology from the University of South Alabama. This is my second GIS course, the first of which was focused only on archaeology, so I am excited to get a broader understanding of GIS. I am hoping to gain a really solid foundation in GIS that I will be able to apply to my future career in archaeology. I know that GIS is a valuable skill, so I am trying to learn as much as I can! Outside of school, I spend most of my time with my kitten, baking, cooking, hanging out with my friends, and distance running. Here is my story map:  https://arcg.is/TafeO.
Read more