Yosefa Ehrlich
Intro to GIS- Project 8
Extreme Storm Vulnerability in Cape Cod, MA
Project Goals:
Hazard assessments are common and important in areas that are susceptible to
natural disasters by virtue of their environment. This project will be an exercise in
vulnerability analysis. Vulnerability analysis answers the following questions:
1) Which groups of people are must vulnerable during a disaster?
2) What are the greatest environmental hazards in a community?
3) What areas are most vulnerable to disaster in a certain community given the prior
information?
Specific focus will be placed on Cape Cod, MA. As water levels rise and weather
conditions become more variable, islands and peninsulas will be at the greatest risk to
water induced disasters like hurricanes. This project will mirror typical vulnerability
analyses by addressing the same questions. It will also take the analysis one step further
by looking at accessibility to emergency services like hospitals and police stations.
Ultimately, I hope to compile two main categories of maps. The first will deal
with socially vulnerable pockets. A series of maps will focus on a specific socially
vulnerable group based on age, income, background etc. Then a final social map will
compile risk assessment on a four item scale where 1 is low risk and 4 is high risk by
collapsing information from the previous series of maps.
The second will focus on infrastructure vulnerability by determining proximity to
important emergency resources (hospitals, fire stations, police stations etc.) where areas
that are further from the resources are more vulnerable. Again, information from a series
of maps will be collapsed into a four item scale to show which areas are most vulnerable
due to lack of infrastructure access.
A few final maps will be included that deal with land use and environmental risk.
Specifically, I aim to create a land use map to see what areas of block groups are most
developed and therefore probably house the most people. This map will serve as a visual
tool to show city planners where people are most densely congregated to aid in an
emergency situation. Additionally, I will include a map with flood plain data, as this layer
takes into account environmental conditions that render an area vulnerable.
Methods:
Part I. Social Vulnerability Mapping
1) Add Massachusetts county and block group data layers from MassGIS under
Political_Boundaries and Census2000.
2) Select by location for Cape Cod counties (Barnstable) and block groups.
3) Export data layer and save the clip to use as the main template.
4) Insert relevant block group data layer from Census2000 (e.g. HH_Size_Family)
and join layer to block group using Logrecno.
5) Open properties  symbology  Fields ‘value’ and select the proper layer within
the household size family (F_HSHLD_7). Make sure it’s classified as natural
breaks with 4 classes.
6) Open attribute table and create a new field (under the ‘options’ button on the
bottom). Save as Fam_7_Plus.
7) Under the options tab click ‘select by attributes’ and set the field value
(F_HSHLD_7) to less than the lowest 25% of the natural breaks. For example, if
my the four classes break down to 1-5, 5-10, 10-15, 15-20 I would set
F_HSHLD_7 < 5.
8) Whichever fields in the attribute table that apply to that characterization will be
highlighted. Right click the new field- Fam_7_Plus, and click field calculator.
9) Set Fam_7_Plus = 1 to signify lowest vulnerability.
10) Repeat for the remaining 75% until you have classified all the data 1-4.
11) When finished, you can remove the join from the attribute table, so only the new
field remains.
12) Repeat for all census information.
Part II. Infrastructure Vulnerability
1) Insert relevant layer file from M/State/MA/MassGIS/Infrastrucute (e.g.
PoliceStations).
2) Select by location to the Cape Cod county block group (so that all the information
stays in the same attribute table) and export the clip. Save clip under Hdrive_Final
Project_ shp.file. (Cape_Cod_PoliceStation)
3) Add the layer and delete the original police station.
4) Activate spatial analyst by opening ‘tools’  ‘extensions’ and clicking ‘spatial
analyst’. You can activate the tool bar under ‘view’  ‘toolbars’.
5) Open spatial analyst ‘options’  ‘distance’  ‘straight line’
6) Under ‘distance to’ set it to Cape_Cod_PoliceStation and set the ‘cell size’ = 30
7) Open spatial analyst ‘options’  ‘zonal statistics’. Set ‘zone field’ = logrecno. Set
‘value raster’ = Distance to Cape_Cod_PoliceStation. Select ‘ignore NoData
caluclations’ and ‘join output table’. Unselect ‘chart’. Save as PoliceStation_Dist
(under zone_tables in H drive). Click OK
8) Open Cape_Cod_Blkgrp_LegAttrib attribute table. Under options (on bottom)
add new field ‘Poli_Mean’ and set ‘type’ = double (because numbers have
decimals).
9) Right click on the new field (Poli_Mean) and open field calculator. Set it = to
PoliceStation.Dist_Mean (at the bottom of the options) by double clicking it.
10) Back in the attribute table add another new field under ‘Poli_Dist’. Set the type =
short integer.
11) Back in data view right click Cape_Cod_Blkgrp_LegAttrib and open its
properties  symbology. Set field value to Cape_Cod_Blkgrp_LegAttrib. Poli.
Mean. Make sure its broken into 4 classes under natural breaks.
12) Return to attribute table for Cape_Cod_Blkgrp_LegAttrib and under options click
select by attribute. Set PoliceStationDist.Mean< 5 (as explained above it’s the
lowest 25%)
13) Left click new field Poli_Dist and select field calculator. Set it to = 1 to signify
lowest vulnerability.
14) Return to attribute table and click options- select by attribute again. This time set
Poli_Dist >=5 AND Poli_Dist < 10. \
15) Repeat the same procedure with field calculator only set it = 2.
16) Repeat for the remaining 75% until you have classified all the data 1-4.
17) When finished, you can remove the join from the attribute table, so only the new
field remains.
18) Repeat for all infrastructure information.
Data Layers (includes maximum accuracy required and file location):
Infrastructure:
Schools
+/- 5 meters
Police stations
+/- 5 meters
Hospitals
+/- 5 meters
Airports
+/- 10 meters
Fire stations
+/- 5 meters
Railroads
+/- 10 meters
M/State/MA/MassGIS/Census2000/
Infrastructure
M/State/MA/MassGIS/Census2000/
Infrastructure
M/State/MA/MassGIS/Census2000/
Infrastructure
M/State/MA/MassGIS/Census2000/
Infrastructure
M/State/MA/MassGIS/Census2000/
Infrastructure
M/State/MA/MassGIS/Census2000/
Infrastructure
Social Vulnerability: (census data)
% 65 +
# of Households with 7 + people
% Low Income
% Non-English by household
% 18 –
# of Buildings built before 1959
% Minority
Male Population 25+ with high
school diploma
Female Population 25+ with high
school diploma
# of workers 16 + who commute to
work by car/ van/ or truck
Environmental Vulnerability/ Land Use:
Hydro 25K
Flood zones
+/- 20 meters
+/- 10 meters
LegAttrib
LegAttrib
LegAttrib
LegAttrib
LegAttrib
CEN2K_BG_HOUS_STRUCT_AGE
LegAttrib
CEN2K_BG_ED_ATTAIN_GEN_AGE
 M_HSGRAD
CEN2K_BG_ED_ATTAIN_GEN_AGE
 F_HSGRAD
CEN2K_BG_TRNS_COM_MEANS 
CTV
Physical_Resources
Not sure- found website saying Barnstable
will be mapped within next 4 years
(http://www.mass.gov/mgis/fema_mod.htm)
Impervious Cover
(NLCD)
Land Use
+/- 25 meters
M/Country/USA/NLCD/Landcover
+/- 25 meters
M/State/MA/MassGIS/Layer
Files/LandUseTransparent (1999-21 classes)