Tracking Turkeys

It’s a sad day for Meleagris gallopavo, the American wild turkey (also domesticated turkey).  Turkeys all over the U.S. are wearing disguises and hiding today in the hopes that they won’t be the main attraction at the Thanksgiving feast.  So, where are these turkeys hiding?

The BISON (Biodiversity Information Serving Our Nation) database contains occurrence data for millions of species. I decided to see if I could track down those sneaky turkeys. My search returned 324,274 results.

Normally, when I search BISON, I get point data. But, turkeys are so common in the U.S. that I got a heatmap.


As you can see, the turkeys are hiding in Wisconsin.

My older kids use to make turkey jokes. They seemed to feel that turkeys aren’t highly intelligent birds. But, the decision to hide in Wisconsin shows that turkeys are much smarter than we think.

The current weather map shows that it’s pretty cold in Wisconsin- not cold enough for a turkey to freeze, but cold enough that someone hunting a wild turkey for Thanksgiving dinner would be seriously tempted to give up, go home and drink hot chocolate.

weather map

But, this post isn’t really about clever turkeys or cold weather or even Thanksgiving dinner. It’s definitely not about geology although I think I could probably find a geological reason for turkeys to gather in Wisconsin. It’s about data.

Today data is everywhere. It’s easy to go online and find data for anything from the number of wild turkeys in each state (based on publications, not actual counts) to the weather to each state’s most Googled Thanksgiving dish (according to the New York Times, it is brownberry stuffing  in Wisconsin). It’s just as easy to use the abundance of data to support any argument you feel like making. Today, I’m arguing that turkeys are Packers fan.

Most popular football team by state


Happy Thanksgiving!


11/26 updated to repair image links.


Mapathon at George Mason University

On Friday, November 20, 11-year-old Arielle and I attended a GIS week map-off at George Mason University. Students from George Mason and Northern Virginia University competed against students from George Washington University while using Open Street Map.

Arielle has attended several mapathons and is quite good with Open Street Map, so we chose the intermediate project. We digitized buildings on imagery from villages in Indonesia that are located near active volcanoes.

I felt it was important that Arielle understand why we are tracing squares on a map. I asked Arielle, “Why does this matter?”. She understood the difference between imagery and maps and that it is important to know what was at a location before a natural disaster in order to estimate damage and direct rescue efforts.

The event was sponsored by Missing Maps, NOVA Community College ASPRS club, George Mason University ASPRS club, Peace Corps, National Geographic, and MapGive.

Are you a better mapper than my 6th grader?



New York: Why the Height of a Skyscraper Depends on Location

Take a look at the New York City skyline. It’s unique and recognizable because of its skyscrapers. New York City is home to some of the tallest buildings in the world.

Suppose you are interested the height of skyscrapers in New York City. You could make a list of building heights, like this list from Wikipedia.

  1. The Freedom Tower, One World Trade Center (1,776 ft.)
  2. 423 Park Avenue (1,400 ft.)
  3. Empire State Building (1,250 ft.)
  4. Bank of America Tower (1,200 ft.)
  5. Chrysler Building (1,046 ft.)
  6. The New York Times Building (1,046 ft.)
  7. One57 (1,005 ft.)
  8. Four World Trade Center (978 ft.)
  9. 70 Pine Street (952 ft.)
  10. The Trump Building, 4o Wall Street (927 ft.)

This list tells me that the Empire State Building is the third tallest building in the City. It tells me that Freedom Tower is about 750 feet taller than the Chrysler Building. But, what does that look like?

I’d get a better idea of what this means with a bar graph. Or. I could use an image like this (also from Wikipedia):


This gives me a much better idea of how building heights compare. But, this information is still limited.

What if I want to know where these buildings are? What if I care about their locations? I will need a map.

I used the Building Footprints shapefile from NY OpenData to create this map of buildings with a roof height over 500 feet tall in NYC. Only 177 out of 1,082,433 buildings in NYC are over 500 feet tall. Those buildings are indicated in red.



The most interesting thing about this map is that all these very tall buildings are clumped in two locations: Midtown and the Financial District. You can see these clumps in this photograph:


Here’s a closer look:TallBuilding2.What is going on? Did New York City specifically zone these locations to have tall buildings? Is this meant to preserve the skyline? Or, is it intended to show the importance of the Financial District?

The answers can also be found in a map. The location of New York’s skyscrapers is all about geology. As you can see in my hideously ugly geological map (colors courtesy of USGS’s New York Geological Map downloaded as a shapefile), the island of Manhattan has a different type of surface rock than the surrounding area. This bedrock is a metamorphic rock called the Manhattan schist (in pale lavender).


The Manhattan schist formed more than 400 million years ago when a volcanic island arc (similar to today’s Japan) crashed into the eastern side of the continent of Laurentia forming a huge mountain range known as the Taconic Orogeny. The high temperatures and pressures associated with mountain building caused the clay minerals in the mud that accumulated of the coast of Laurentia to transform to more resistant minerals such as biotite, muscovite and quartz.

manhattan schist
Manhattan Schist

Throughout most of Manhattan, this erosion-resistant bedrock is covered with large amounts of unconsolidated sediments. But,  this exceptionally hard rock lies very close to the surface in Downtown and Midtown Manhattan. Because this rock is so strong, it makes the perfect foundation for a skyscraper.

What about other cities? There are only two structures over 500 feet tall in Washington DC: the Hughes Memorial radio tower (761 ft) and the Washington Monument (555 ft). Why doesn’t Washington DC have tall skyscrapers?

While there are some strong metamorphic rocks in Northwest DC, most of DC is built on much softer sedimentary rocks. These rocks cannot support a skyscraper.

So, maps can help us understand where things are, but they can also help us understand why they are where they are. In New York, the height of a building depends on location and location depends on geology.

(Many of the other tallest buildings in the U.S. are located in Chicago. Chicago is weird. You can learn more about the challenges of building skyscrapers in a swamp here. )

This post was inspired by Episode 1 of Making North America on PBS.





Geology Matters: Watersheds in Fairfax County

On November, 11th, Greg Bacon, an analyst at Fairfax County GIS, came to talk to the GIS 295 class about his work and the data available online at the Fairfax County Geoportal website.

The website contains information about public services, land records, land development, transportation (a big deal in Northern Virginia), safety, amenities, elections, and wildlife – basically, all the county information that your average citizen or business might need. At the very very bottom of the page, you will find watersheds.


A watershed is all of the land that drains into a particular body of water. Watersheds occur at all scales. The United States is divided into two great watersheds by the Continental Divide, a line of high peaks stretching from the Andes through the Rockies that divides land that drains into the Pacific Ocean from land that drains into the Atlantic Ocean. You can see the continental divide on the map below.continental divide

The Rocky Mountains of the U.S. formed through a series of continental plate collisions. The most recent is the Laramide Orogeny that occurred between 80 and 55 million years ago. At that time, the Rockies were about 6,000 meters above sea level.  Today, the highest peak is Mount Elbert at 4,401 meters.

While the Continental Divide determines which ocean water ultimately ends up in, there are many ways for water to get to those oceans. The U.S. Geological Survey (USGS) uses hydrologic unit codes (HUC) at six different scales (2,4,6,8,10,12) to designate the area of land that uses a particular water body as a path to the ocean. In this map, you can see HUC 2 or regional divisions. Unlike other watershed models, the USGS’s model is based entirely on water drainage – not state or local administrative boundaries.

HUC2 Fairfax County is in the HUC 2-02 watershed boundary, or mid-Atlantic region.  If I zoom in, I can see that Fairfax County is also in HUC 4-207.  Drainage in this region flows into the Potomac River. If Fairfax County was further north, water would flow into the Susquehanna. If it were further South, water would flow into the lower Chesapeake. The upper Chesapeake watershed is to the east.huc4

At the HUC 6 level, most of Fairfax flows into the Middle Potomac. However, the rivers used to  get to the mid-Potomac differ. That causes the area to be divided into the Anacostia-Occoquan and the Catoctin district (northwest).

The area continues to be subdivided until the HUD 12 level which is based on local creeks and lakes – a resolution that is very similar to the Fairfax County dataset. The Fairfax County system continues to subdivide regions to the level of individual creeks and streams, but one must click at the “more info” tab on the mapped watersheds to learn about these subdivisions.


There is one important difference between the Fairfax County watershed designations and the USGS system. The Fairfax County watershed boundaries end at the county line. The USGS boundaries do not. That is because the USGS watersheds are based on geology. The Fairfax County watersheds are based on administrative boundaries.

I looked up the Cob Run and Bull Run watersheds on the Fairfax County website. This area is located in southwestern Fairfax County between Loudon and Prince William Counties and covers 64 miles of land that drain into tributaries of the Occoquan Reservoir.  The website says that 14 square miles in Loudon County also drains into this watershed.  This matters.

We all need clean water. Yet, the conveniences of everyday life (manufacturing, transportation, agriculture) create pollution that is carried into our drinking water. In Fairfax County, all drinking water comes from the Potomac or the Occoquan.

All water that falls or accumulates in a river’s watershed goes into that river. This includes the rain that falls on the roads and mixes with the oil and gas that cars leave behind It includes chemical-laden runoff from industry and farms. It even includes the water that washed off your neighbor’s yard after he sprayed his azaleas. Although, this water is cleaned and treated, small “safe” amounts of contaminants remain.

Fairfax County, like all counties, must consider water pollution when planning for the future. The County must answer questions like “How will expanding Route 28 increase runoff into Bull Run?”,  “How much of that water will end up in our drinking supply?”, and “How will that water be treated?” What happens when Manassas doesn’t care because commuters are sick of sitting in traffic and the creek is across a county line? Or, when an administrator uses the map without reading the metadata? Wouldn’t it be better to stick with the USGS system which is based on the way the Earth actually works and then figure out the overlap?

As a geologist, I know that a watershed is all of the land that drains into a particular body of water.  I’m uncomfortable with the Fairfax County map; anyone want to offer reassurance?

Where Will I Put the Bottled Water?

When we were in class on Wednesday night, Hurricane Joaquin seemed to be headed straight for Virginia. I’m pretty well prepared, but I donated last year’s bottled water stash in the spring. So, on Thursday morning, I stopped at Target to stock up on bottled water which is now sitting in the hallway because I don’t have space for it.

The latest forecasts show that I didn’t really need to rush and buy water; Joaquin isn’t likely to reach the East Coast. But, thoughts of hurricanes inspired a map.


I mapped esri’s active hurricanes and recent hurricanes as well as hurricane tracks from historic hurricanes (in blue, from on top of a base map. Hurricane Joaquin’s path is shown in black, while the yellow dots represent the tracks of recent hurricanes. As you can see, we might be safe from Hurricane Joaquin, but (historically speaking) it’s only a matter of time until a hurricane does hit Virginia.

You can see the ArcGIS Online map here.

I think I’ll keep the water.


Hi, I’m Sara Lubkin. I am a GIS certificate student at Northern Virginia Community College.

I am also a geologist who studies fossil insects, paleoclimate and the current effects of climate change. I earned my PhD from Cornell University in 2008 and worked in web and social media marketing for a while.

I now teach introductory geology classes at the University of Mary Washington. When I’m not teaching or learning, I do research. I am currently collaborating with the NASA DEVELOP Program and the Virginia Institute of Marine Science on a project tracking harmful algal blooms (HAB) in the Chesapeake Bay. I am also a mom.

For me, GIS is connecting data to geography. When non-scientists ask me what GIS is, I tell them that I put information on maps so I can better analyze and interpret.  I was a scientist before I studied GIS, but GIS has allowed me to ask and answer different types of questions.

Before studying GIS, my fossil insect research focused on describing new species and determining how species were related to other species and modern species. I was getting frustrated with this work and wanted to do something more meaningful. Now, I am able to connect Pleistocene fossil insect species to specific climate zones and create maps of Pleistocene glaciation. I am hoping to use this research and my work with NASA DEVELOP to transition into the study of climate change and its effects on the Earth.