Janet Tilley earned her B.S. in Geology and a
Certificate in Cartography from George Mason
University, Fairfax, Virginia in 1994. She came to USGS from the Department of Agriculture in
1989, where she was working with satellite image interpretation and digitization techniques for
over 6 years.
Janet has been working with a multi-discipline/agency team that includes William Acevedo, Penny
Masuoka, Dr. Timothy Foresman and Susan Clark, and others for the last 2 1/2 years to develop a
200 year GIS temporal data base that captures changes upon the land as impacted by humans.
Special Interests
The NMD temporal mapping activity was first done by USGS in the San Francisco-Sacramento,
CA., area by William Acevedo and Len Gaydos, USGS, and brought to us, per Timothy
Foresman's request, to the Reston USGS to pursue temporal mapping in the Baltimore-Washington region. The next paragraph provides background information about this work and is
where my interest lie. I especially would like to learn more about modeling techniques as I often
must present the overall project, applications, and modeling concepts that are currently underway.
I need to better understand this application. I am not a programmer, but does that mean I will not
be able to do modeling?
Background
The U.S. Geological Survey, the University of Maryland Baltimore County, and the U.S. Bureau
of Census have developed a temporal database to study urban development in the
Baltimore-Washington region. The primary data layer, the extent of urban or built-up areas, was
compiled using a geographic information system and historical maps, remotely sensed data, digital
land use data, and census information from a variety of sources. Urban land use change has been
documented by the Baltimore-Washington Spatial Dynamics & Human Impact Study Team for
the last 200 years. The methods, definitions, and collection criteria were used to define urban
or built-up areas were developed by a multi-disciplinary team that also ensured consistency in
collection techniques and documentation methods for subsequent application in other regions.
Animation techniques were used to visualize the database and to document the evolution of the
region's urban landscape. The principal transportation data layer documents the primary roads,
railroads, and other transportation features that provided the infrastructure for urban
development. Compilation criteria, developed by Susan Clark, USGS, such as connectivity, mobility, lineage, and alignment were developed to accommodate limitations in the source materials. A
nimating transportation features proves difficult as they are linear features and challenging to blend in and out through time, data have been refined by William Acevedo. The database is an important tool to urban and regional planners, ecologists, and g
lobal change researchers for measuring trends in urban sprawl, analyzing patterns of water pollution, understanding the impacts of development on ecosystems, and developing predictive modeling techniques to better forecast areas of urban growth. Web page
s created by Len Gaydos, William Acevedo, and Janis Taylor Buchanan discussing
detailed information about Land Transformations, San Francisco-Sacramento, CA., and
Baltimore-Washington, VA-MD-PA-WV., work are available; as well as Timothy Foresman,
UMBC, web pages discusses the collaboratory and has our data that can be downloaded for
further analysis.
Applications
Currently, there are several activities that are using temporal data from the San Francisco-Sacramento and Baltimore-Washington regions for applications and modeling. In applications of
these types of data the Chesapeake Bay Program is using the urban temporal theme to correlate
the urban growth with the change in water quality. Such issues as nutrient loading and sediment
run-off are of special concern in their impact on fragile ecosystems.
William Acevedo, USGS, is testing the feasibility and generating a temporal agricultural land
theme for the Patuxent watershed; and Timothy Foresman, UMBC, is testing the feasibility and
generating a temporal forested land theme in the Gwynns Falls Watershed in Baltimore, MD.
Both of these research endeavors are being completed for the Chesapeake Bay Program. Again the
Chesapeake Bay Program will use these data to correlate with the water quality.
Modeling and Prediction
Modeling and prediction techniques of both the San Francisco-Sacramento, CA., and Baltimore-Washington, VA-MD-PA-WV., areas are being researched by Keith Clark, UCSB. One
modeling technique he has applied is the application of a wild fire algorithm to that of urban
sprawl. Lee De Cola, USGS, has also completed fractal modeling of the Baltimore-Washington,
VA-MD-PA-WV., area, where he generated urban surface intensity animations of our data.
Future Research
This multi-discipline team is hoping to pursue the opportunity to refine their research on
developing tools for generating these temporal databases, and hoping to build lasting partnerships
to pursue these endeavors. Our current tools are crude and the technology could not be passed
on to other groups in additional metropolotan areas. We are anticipating developing databases
for the following four cites: New York, NY., Philedelphia, PA., Chicago, IL., and Portland, OR.
In the anticipation of the opportunity to continue this research we are investigating source
availability, and are beginning to establish contacts for additional partners and source materials in
these areas.