Mapping Matthew

Hurricane Matthew was a Cape-Verde type hurricane that quickly but briefly reached category 5 status in the Caribbean Sea and ran along the eastern United States coast for three days before dissipating off the coast of North Carolina into the Atlantic.

Forecasting the movement of a hurricane is a huge deal in the meteorological community for reasons of public safety and risk assessment. Mapping the track of hurricane after it has passed can be just a fun and is definitely a good exercise for developing GIS skills.

hurricane-matthew-nicole-weather-underground

Acquiring data is always the first step and for this project Weather Underground had a robust table of information about the track of the storm including latitude and longitude data which alleviates the need to covert this data into something ArcMap can read.

Copying and pasting this information into an excel document and saving it in either a .txt, or .csv format allows it to be direcly imported into ArcMap. Once it’s in the ArcMap table of contents we can right-click  and select “Display XY data”. Since latitude and longitude data is present, ArcMap can automatically relate the data and create a shapefile. Oh course, the geographical coordinate system will have to match the basemap, in this case WGS 1984, in order to display correctly.

After the data is on the map, the next step is applying the graduated symbology to visually present the strength of the storm at the different data points. In the excel spreadsheet, I used the “replace” command to replace the “tropical storm” status to 0 and the “category 1-5” to their corresponding numbers. This makes it easier for ArcMap to interpret the data.

Hurricane Nicole was added in a similar manner to provide or more complete meteorological picture of the region at the time. The Hurricane Nicole data on Weather Underground didn’t have category information so I went ahead and converted the wind speed, which is provided, to the 0-5 storm intensity scale. Perhaps the data is incomplete because, at the time of this writing, Hurricane Nicole is still an active storm.

Assembling the legend is always an interesting part of the design process. I discovered the “convert to graphics” option and the “group” and “ungroup” options by right clicking on the legend. This makes editing the legend and adding fields and design elements manually noticeably easier. However, once you covert to graphics you lose the some editing functionality so it’s best to make sure all legend elements are included and finalized.

I wanted the labels to be a big part of this map to accurately convey the movement of the storms by notating the dates of certain points. Adding the labels for the “date” field for both of the tracks put more labels than were necessary. I only wanted one label per date and several points shared the same date, cluttering the map. Right clicking on a layer will bring up the context menu and toward the bottom is an option to “Convert labels to annotations”. This conversion is similar to converting the legend to a graphic in that it allows more creative freedom to manipulate individual elements. Once the labels were converted to annotations, I was able to delete the repeated dates until there was an optimum and aesthetic labeling distribution.

In the future I’d like to create a similar project but use the XY to Line or Point to Line tool to create a continuous projection of data. The data must have a unique identifier to use this tools which this Weather Underground data doesn’t have by default. I enjoyed making this map. If I had all of the time in the world I’d like to get a formal metereological education.