Implementation of Geospatial Technology in Woodlawn Cemetery

Implementation of Geospatial Technology in Woodlawn
Cemetery, the Bronx
Yuri Gorokhovich
Susan Olsen
Department of Earth,
Environmental and Geospatial
Sciences
Gillet Hall 315, 250 Bedford
Park Blvd. West, Bronx, NY
10468 718-960-1981
Woodlawn Cemetery
Webster Avenue & East 233rd
Street, Bronx, New York
10470
718-920-1463
yuri.gorokhovich@lehma
n.cuny.edu
solsen@thewoodlawnce
metery.org
Mary Gray
Department of Earth,
Environmental and Geospatial
Sciences,
Gillet Hall 315, 250 Bedford
Park Blvd. West, Bronx, NY
10468
[email protected]
ABSTRACT
1.INTRODUCTION
In this paper we describe results of the partnership between
Department of Earth, Environmental and Geospatial Sciences
(DEEGS) at Lehman College (City University of New York) and
Woodlawn Cemetery, a historical landmark in the Bronx. This
partnership was built on the development and application of
Geographic Information Systems (GIS) and spatial hydrologic
modeling to help Woodlawn Cemetery with their geographic data
management and analysis. Particular problems that were
addressed included “matching” historical plans and modern aerial
photography imagery for digitizing plots, graves and mausoleums
and use of geospatial technology for hydrologic modeling to
identify sources of erosion in the Woodlawn lake that damages
cemetery monuments. Both projects were conducted during the
last five years (2010 – 2014) and partnership still continues in the
area of data management (e.g. tree surveys and geological
assessment of monument materials for preservation and
conservation). The partnership proved to be extremely beneficial
for both organizations. Conducted projects improved technical,
social and business skills of students. Woodlawn cemetery saved
thousands of dollars on consulting fees and gained local
community support from Lehman College.
The Woodlawn Cemetery in the Bronx is one of the oldest
cemeteries in the country and is a historical landmark in New
York City (NYC) visited by thousands of tourists every year. It
was established in 1863, began internments in 1885 and was
designated a National Landmark in 2011. It contains more than
300,000 monuments, many representing artistic and historical
value. The Woodlawn Cemetery also serves NYC community and
tourists by providing cultural and art services, e.g. jazz concerts,
various topical tours and topical research.
Protection and management of the cemetery requires
comprehensive geographic database serving as a base for mapping
and management of each unit in the cemetery (i.e. grave,
mausoleum, individual plot, etc.).
Geographic data consist of spatial component (i.e. location)
defined as coordinate pair and non-spatial component (i.e. data
about location) stored in a special database. Both components are
connected to each other and form Geographic Information System
(GIS), a software for analyzing, displaying and managing spatial
information. GIS can be applied on a small (e.g. country or world)
and large (e.g. cemetery or borough plan) geographic scales. A
specific issue for the Woodlawn Cemetery was that historical
plans of the cemetery existed only on the paper without proper
documentation of geographic coordinate system necessary to
build GIS.
Categories and Subject Descriptors
Geographic Information Systems, spatial interaction
General Terms
Management, Measurement, Documentation, Design, Verification.
Keywords
GIS, aerial imagery, digitizing, hydrology, modeling.
Bloomberg Data for Good Exchange Conference.
28-Sep-2015, New York City, NY, USA.
This issue could be resolved in two ways: 1. Conducting full new
survey of the cemetery monuments; 2. Digitizing, georeferencing
and spatially adjusting old historical plans to the modern aerial
photography and using it as a base for developing GIS. The first
proposition was prohibitively expensive. The second proposition
required technical solution based on principles of spatial
adjustment and georeferencing. This refers to the GIS methods of
“matching” spatial/geographic location of features in digital
media and their real-world locations (e.g. aerial imagery data or
satellite imagery).
Building GIS database was not only beneficial for the mapping
and computerized storage of information. It provided a basis for
the analysis of coastal erosion in the Woodlawn Lake within the
cemetery. The erosion caused some monuments to drown and
some to tilt, creating enormous problems for monument’s
conservation and maintenance. GIS data combined with basic
hydrologic and terrain modeling technique helped identifying
possible causes of erosion.
2.METHODOLOGY
2.1.Building GIS Database
Each individual feature was then linked with archival cemetery
records in GIS software using identification number (ID) system
unique for each cemetery unit (Figure 2). Thus any archival
information (e.g. age, race, cause of death, etc.) can be visually
displayed, queried and analyzed within GIS software.
The main basis for this work was a collection of historical
surveying paper plans of the cemetery. These plans contained
surveyed locations and dimensions of each cemetery unit. While
measurement units were known, their geographic coordinates
were not. We decided to use geographic projection system
Universal Transverse Mercator (UTM), zone 18. This is a standard
spatial reference system for many NYC maps and GIS data.
All historical plans of the Woodlawn Cemetery were scanned with
high-resolution scanner and converted into standard JPEG image
files. These images contained identification number for each grave
and plot; however they still could not be digitally linked with nonspatial data about each plot, grave of monument because image is
not a discrete entity. To rectify this we used GPS field survey and
manual spatial adjustment in GIS software ArcGIS to “match”
high-resolution (12 inch) aerial photography with scanned plans
within UTM projection system. Figure 1 shows aerial imagery on
the background and scanned features from historical plans on the
foreground (yellow color). Green dots are centroids of the
cemetery sites digitized later, after scanned historical plans were
georeferenced.
!
Figure 2. Using plot ID numbers for labeling graves in ArcGIS
2.2.Using GIS data for hydrologic modeling
One of the attractions of the Woodlawn Cemetery is the
Woodlawn Lake. Urbanization of the Bronx, that began around
1900, developed the upper watershed land, adjacent to the
Woodlawn Lake, into a residential zone. Figure 3 shows the
surrounding conditions of the Woodlawn Lake such as old part of
the cemetery, urbanized areas, etc.
!
Figure 1. Aerial imagery combined with data from historic
plans
After all scanned plans were properly georeferenced at Lehman
College according to the accuracy of aerial imagery another group
of students from DEEGS started digitizing cemetery plots,
individual graves and mausoleums. These data were digitized as
points (e.g. graves) or polygons (e.g. plots, mausoleums, tombs).
!
Figure 3. Woodlawn Lake and surrounding environments.
We hypothesize that urbanization after 1900 caused increase of
the surface runoff and uneven volumetric fluctuations of the lake
level influencing erosion of the coastline and deterioration of the
adjacent monuments. To test this hypothesis we applied GIS to
identify topographic and land cover changes that could possibly
influence hydrologic conditions in the lake. Using various runoff
coefficients and formulae for the surface runoff we calculated
maximum current runoff considering urbanized areas north from
the cemetery and maximum historic runoff when cemetery was
surrounded by natural land cover. Figure 4 shows the comparison
between this data.
!
Figure 4. Comparison of surface runoff (Q) between current
and historic modeling.
We found large differences in surface runoff (3.1 vs 0.9 cfs)
comparing historical (farmland) and current conditions of the
watershed, supporting the original hypothesis. We also found that
the surface runoff is affected by both urbanization and the
cemetery monuments to different degrees. Further exploration of
these and other factors can modify or even change the original
hypothesis.
3.RESULTS AND FUTURE WORK
The partnership between DEEGS at Lehman College and
Woodlawn Cemetery provided benefits to both organizations.
Lehman College students gained practical experience in GIS
application and Woodlawn Cemetery saved thousands of dollars
for consulting work. Students took part in meetings with cemetery
staff and learned how to manage and plan GIS work. This would
be impossible in traditional university settings. Technical
difficulties enhanced student’s abilities to work with various types
of data and integrate them in manageable way. At the same time
Woodlawn Cemetery staff learned new tools and obtained GISbased data management system. This also helped Woodlawn
cemetery staff to strategize on grant applications and consulting
projects.
Future work with Woodlawn Cemetery staff will concentrate on
improvement of hydrologic modeling, finding the cause of
shoreline erosion in the Woodlawn Lake and providing
recommendations for the shoreline stabilization. Established GIS
database will be updated with geologic data on monuments and
tree conditions. Geologic conditions of monuments include rock
type and its weathering conditions, properties, origin. This will
help in maintaining monuments and planning for the conservation
and renovation activities. 4.ACKNOWLEDGMENTS
Our thanks to the staff of Woodlawn Cemetery who provided
wonderful project, practical experience and financial help to
Lehman College students participating in this work. Chief
archaeologist Jim Miller provided invaluable guidance and
expertise on work with cemetery archival data and GIS database
design.