Our internal auditors found increasing numbers of GPS points with poor accuracy and asked our Data Center to analyze the metadata.
Our data came in .csv file format but our GIS team had just received a four-hour introduction session to FME. Realizing that FME could save time and effort, I asked our recent hire, a FME certified trainer, to mentor me as I attempted to create various reports to aid field managers in technician training.
I needed to pull the files from our archives and used two string search and an attribute manager transformer to select the required file paths. My mentor helped me set up a feature reader to get the file paths and then a tester to confirm every technician and date to set up a keep file path transformer. Once I had the files, I put a feature reader to hold the data from the .csv files and created three tiers of analysis. First, I created a summary of the total number of GPS satellites and precision readings, putting the results on separate tab in an excel file. Next, I generated summaries noting the satellites and precision readings by technicians. Then, I sorted the individual daily results. Finally, I created a file geodatabase from those selected GPS points and used spatial tools.
The results showed little urban canopy; however, approximately 20 percent of the data had zero to two satellites available when the points were taken. Accurate GPS positioning is not possible with that few satellites. From the individualized technician reports, we noticed several technicians had significantly poorer satellite reception than others; however, in the Data Center, we were unable to determine if those results stem from training or equipment. The field supervisors will need to retrain those technicians and keep close tabs on equipment to improve on GPS data.
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AEC (Architecture Engineering and Construction)