Using The GIS Database

A GIS, or Geographical Information System, is designed to handle spatial or geographical data. The information can be captured, stored, analyzed, processed, and manipulated to build reports for all manner of purposes. Sometimes, the data provided by the GIS is used as a framework for further reporting, such as a recent GIS Services’ poster comparing the 2015 Rowlett tornado with one that touched down in 1959.

Bre's PosterThe Rowlett tornado touched down on December 26, 2015. The GIS team was able to use the data to estimate the likely economic land cost of the tornado at $2.7 billion. The 1959 tornado was on the ground for almost fifteen miles longer than the 2015 tornado but was a lesser EF2 storm (the 2015 storm was a EF4 category); it caused less damage at an estimated $1.9 billion in today’s terms. These numbers are impressive but cannot convey the damage and loss of life caused by tornadoes.


Bre Callear from our GIS Team explained that she was interested in looking at the impact of the 2015 tornado because it occurred close to BIS Consulting’s office and at an unusual time of year. By looking through historical tornado data, she noticed that the 2015 and 1959 tornadoes happened in a very similar part of Texas. The team loaded the path of each tornado into the Esri ArcMap software to see that the southern parts overlapped, which led to the comparison between the economic damage caused.

Collin Poster

Collin King, also from our GIS team, has used the tornado data to produce a poster but this was instead designed to determine the safest quadrant to live in Dallas County based on four factors – the safest quadrant was based on coverage, on injuries and fatalities, on the average magnitude of the storm, and ground covered by the tornado per casualty. Collin imported data from the Storm Prediction Center and Government Land Office. Each tornado track was clipped into its respective quadrant and the numbers crunched to answer the questions. The results show that the Northwest quadrant has the least chance of a tornado hitting you based on coverage, but it has the highest ratio of injuries and deaths by land mass. The Southeast quadrant has the lowest average magnitude of storm and ground covered. The Southwest, the safest, has the lowest injury and fatality rate, and best ratio of acreage to injuries and fatalities.

In these two examples, that were presented at SCAUG 2016, the GIS team used tornado data combined with the GIS database for further analysis. However, Bre explained that the data may be combined with many other sources and tasks, but “…the difficulty is finding complete and usable data.”

If you have an idea of what the team can investigate next, let us know in the comments below.