Emergency Preparedness:Using Local and Federal Data and ArcGIS to Analyze Potential Human and Economic            Impacts ...
Outline   What This Presentation Covers   Brief Background of Flooding in Reno, Nevada   Project Goals and Information ...
This presentation covers howGIS professionals can:   Perform overlay analyses of spatial and    demographic data from fed...
Truckee River Flooding   The Truckee River flows    from Lake Tahoe in    California and through the    hearts of the adj...
Area of Interest                      East of City of Sparks,                        a narrow canyon                      ...
Project Goals -- Info for EmergencyResponse Staff …   Identify facilities and populations that may at    risk and require...
… and for Decision-Makers   Identify city’s current building values and    property taxes for parcels in flood extents   ...
Example – Important Facilities                                 8
Example – Population 65+                           9
Example – Income < $15,000                             10
Example – No Vehicles                        11
Example – Assessed Building Values                                     12
Example – Snapshot of Numbers(Numbers in Table and on Maps are Maximums – See Caveat Later)    Total Population:         ...
Methodology and Data1. Acquire spatial data and re-project as needed.2. Perform overlay analyses (select by location) to s...
Spatial Data                       Spatial DataUsed in Analysis                   Used Only on Maps   Business data (2010...
Spatial Data   Acquire data from local and federal agencies.   Check the coordinate system of spatial data    and re-pro...
http://www.census.gov/geo/www/tiger/                                       17
Select by Location … and Caveat Use Select by Location to get Tracts that intersect the flood  extent polygon. Caveat – B...
About Differences Between the2000 Census and the 2010 Census The 2000 Census included a short-form questionnaire  (data t...
Obtaining Demographic Data   Use Census Bureau’s    American FactFinder. Go    to factfinder2.census.gov   Under “Geogra...
Demographic Data (continued)   Can narrow search by typing in a topic (e.g., Income)    or type in a specific table numbe...
Census Table Numbers Used for Reno   QT_P1 (“Age Groups and Sex: 2010”, 2010 SF1)   S1901 (“Income in Past 12 Months”,  ...
Preview Table Before Downloading                          If the table has                          the info you want,    ...
Download    CSV File   Download CSV                            1    (zipped file).   “In a Single File” is    fine.   I...
Prep CSV Tables in Excel   First, save CSV file as an Excel file. Use    a meaningful file name; keep table name in it. ...
Prep CSV Tables in Excel (continued)    Change table – Rename headings, delete blank &     unneeded rows, maybe delete un...
Change ID Field Types in Excel   In order to join tables in    ArcMap, must change the    field containing unique tract  ...
Join Tracts Shapefile With Excel Table   Add Tracts polygon shapefile and    Excel table to ArcMap.   Right-click on the...
Visualize Data   Make maps, charts, and tables    that emergency response staff    will find useful.   For map symbology...
Resources About Census Data   Census Handbook “A Compass for Understanding and    Using American Community Survey Data – ...
What’s Next For This Project?   Create a short, targeted report.   Check back in a few months for ACS 5-year    estimate...
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2012 Emergency Track, Emergency Preparedness: Using Local and Federal Data and ArcGIS to Analyze Potential Human and Economic Impacts of Flooding, Valerie Johnson

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This presentation focuses on a case study of river flooding in Reno, Nevada. However, the "how-to" information covered is applicable to any community that experiences disasters. Floods have negative impacts on people and businesses located in flood-prone areas, as well as on the finances of local governments. It's important for emergency management staff to have knowledge of current demographics of citizens who are at risk from flooding. Residents who are elderly, lack transportation, and have fewer financial savings and resources may require special emergency response measures. Decision-makers benefit from advance knowledge about the number of and current values of commercial and residential buildings located in flood-prone areas, because their losses could impact local governments' tax revenue.
This session discusses how GIS professionals can 1) perform overlay analyses of spatial and demographic data from federal and local sources to identify potential human and economic impacts of flooding and 2) create visualization products that show results in a format that emergency responders and decision-makers can easily understand. It covers using data from the 2010 Census and the American Community Survey. Users who are familiar with the 2000 Census data but not the 2010 data will benefit from learning about changes that have occurred. This presentation includes examples of 2-D and 3-D maps created using ArcGIS 10.

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2012 Emergency Track, Emergency Preparedness: Using Local and Federal Data and ArcGIS to Analyze Potential Human and Economic Impacts of Flooding, Valerie Johnson

  1. 1. Emergency Preparedness:Using Local and Federal Data and ArcGIS to Analyze Potential Human and Economic Impacts of Flooding Valerie Johnson, johnsonv@reno.gov, Sept. 21, 2012 Pennsylvania State University MGIS Project Advisor: Karen Schuckman Reno-Tahoe Airport, 1997 Flood Downtown Reno, 2005 Flood Photo Source: Truckee River Flood Management Project 1
  2. 2. Outline What This Presentation Covers Brief Background of Flooding in Reno, Nevada Project Goals and Information for Staff Examples of Visualization Products Methodology and Data  Spatial Datasets  Property Building Values  Online American FactFinder for Downloading Demographic Data from the 2010 Census and the American Community Survey (ACS) for Census Tracts  Special Steps in Excel Resources About Census Data 2
  3. 3. This presentation covers howGIS professionals can: Perform overlay analyses of spatial and demographic data from federal and local data sources to identify potential human and economic impacts of flooding (or other emergency). Obtain and prep data from the 2010 Census and the American Community Survey. Create visualization products that show the results in a format that emergency responders and decision-makers can easily understand. Maps, charts, and tables are well-suited for conveying such information in a short, targeted report. 3
  4. 4. Truckee River Flooding The Truckee River flows from Lake Tahoe in California and through the hearts of the adjacent cities of Reno and Sparks in Nevada, before it ends in Pyramid Lake. The Truckee River has a significant damaging flood event about every 10 years.  117-year flood in 1997 caused damages of $650 - $700 million.  50-year flood in 2005 Downtown Reno, 1907 Flood. caused damages of Bridge, built in 1905, is still in use. $18 million. Photo Source: Truckee River Flood Management Project 4
  5. 5. Area of Interest East of City of Sparks, a narrow canyon constricts the river Truckee River 5
  6. 6. Project Goals -- Info for EmergencyResponse Staff … Identify facilities and populations that may at risk and require special public safety response (elderly, very young, limited resources)  Important facilities (schools & colleges, day care, Local medical care, hotels, government buildings, fire Data stations, police stations, etc.)  Population (total; under 5 yrs; over 65 yrs)  Population with disability – Unfortunately, data are currently unavailable at the Tract level Census  Household income (median; household income Bureau under $15,000/yr) Data  Transportation (households without a vehicle)  Your community may want other categories 6
  7. 7. … and for Decision-Makers Identify city’s current building values and property taxes for parcels in flood extents (financial impact of damages)  Buildings that could be damaged by a flood Local (not condos on 2nd and higher floors) Property Appraiser/  Assessed values of buildings Assessor  Net property taxes for entity Data 7
  8. 8. Example – Important Facilities 8
  9. 9. Example – Population 65+ 9
  10. 10. Example – Income < $15,000 10
  11. 11. Example – No Vehicles 11
  12. 12. Example – Assessed Building Values 12
  13. 13. Example – Snapshot of Numbers(Numbers in Table and on Maps are Maximums – See Caveat Later) Total Population: 63,869 Population 5 and Under: 3,651 Population 65 and Older: 9,493 Population 85 and Older: 1,122 Households With No Vehicle: 4,145 Households With Income $15,000 and Less: 4,036 Building Values in 1997 Flood Extent: Assessed: $284,504,502 Net Tax Reno: $9,735,535 Building Values in 2005 Flood Extent: Assessed: $182,845,258 Net Tax Reno: $5,081,778 13
  14. 14. Methodology and Data1. Acquire spatial data and re-project as needed.2. Perform overlay analyses (select by location) to select: A. Census Tracts intersecting city limits polygon and the 1997 flood extent (1997 and 2005 extents = same selection) B. Important facilities intersecting combined flood extent. C. Parcels intersecting each flood extent.3. Download CSV files of Census 2010 and American Community Survey (ACS) data. Review and manipulate tables in Excel. (This is time-consuming!)4. Use ArcGIS to join Excel file to the Tracts shapefile.5. Use ArcGIS to create maps. Use Excel to create charts and tables. Get feedback from staff about what they want to see.6. Produce short, targeted report. Maintain it! 14
  15. 15. Spatial Data Spatial DataUsed in Analysis Used Only on Maps Business data (2010  Hydrographic data InfoUSA point data) (river, lakes, and creeks) Census Tracts (ACS data  Street centerlines & is only at Tract level, not major roads Block Group or Block) City limits Flood extents from 1997 and 2005 events  Your community may want Government buildings other features Medical care facilities (hospitals, nursing homes) Parcels with building values Schools, colleges, day care 15
  16. 16. Spatial Data Acquire data from local and federal agencies. Check the coordinate system of spatial data and re-project as needed. You’ll need the Census Tract polygons because the American Community Survey (ACS) data is available down to the Tract level (not Block Groups or Blocks). Local or state GIS Clearinghouses probably have the Tract polygons. If not, download a shapefile of the 2010 Tracts from: http://www.census.gov/geo/www/tiger/ The Census Bureau also has a shapefile that includes some demographic info from the SF-1 form (population, age, race). 16
  17. 17. http://www.census.gov/geo/www/tiger/ 17
  18. 18. Select by Location … and Caveat Use Select by Location to get Tracts that intersect the flood extent polygon. Caveat – Boundaries of Tracts don’t coincide with boundaries of flood extents, so the count of people/households “in” the flood extent will be larger than reality (they’ll be the maximum scenario). Why? “Select by Location” will Beware - Selected polygons are select the entire Tract polygons shown with magenta outline. (black outline) that intersect the Unwanted polygons like 31.01 may flood polygons. be selected, so check results! 18
  19. 19. About Differences Between the2000 Census and the 2010 Census The 2000 Census included a short-form questionnaire (data tables SF-1 & SF-2) and a long-form questionnaire (data tables SF-3 & SF-4). Starting with 2010, the decennial Census now includes only the short-form questionnaire, covering topics like population, age, and race. Form long-form info like marital status, income, number of vehicles, and disability* are covered in the more frequently conducted ACS (smaller sample size). See “Resources” for links to useful documents, especially discussions about ACS Margin of Error (+/-).* Disability data from ACS 5-year estimates slated to be available after 2012. 19
  20. 20. Obtaining Demographic Data Use Census Bureau’s American FactFinder. Go to factfinder2.census.gov Under “Geographies”, pick “Census Tract” 1 Then choose your state, county, and “All Census Tracts within County” Click “Add to Your 2 Selections” Then close the pop-up window 20
  21. 21. Demographic Data (continued) Can narrow search by typing in a topic (e.g., Income) or type in a specific table number. The next slide lists the table numbers I found useful. 21
  22. 22. Census Table Numbers Used for Reno QT_P1 (“Age Groups and Sex: 2010”, 2010 SF1) S1901 (“Income in Past 12 Months”, 2010 ACS 5-year estimates) B08201 (“Household Size by Vehicles Available”, 2010 ACS 5-year estimates) 3 1 2 22
  23. 23. Preview Table Before Downloading If the table has the info you want, download it. Preview of B08201 – Number of Vehicles 23
  24. 24. Download CSV File Download CSV 1 (zipped file). “In a Single File” is fine. In Excel, you will have to rename column headings, so if you think you will want to refer to original column headings, then 2 choose “Separate Files”. 24
  25. 25. Prep CSV Tables in Excel First, save CSV file as an Excel file. Use a meaningful file name; keep table name in it. Change table – Rename headings in first row, delete blank & unneeded rows, maybe delete unneeded columns, and change field types Table B08201 – Number of Vehicles – in Excel 25
  26. 26. Prep CSV Tables in Excel (continued)  Change table – Rename headings, delete blank & unneeded rows, maybe delete unneeded columns, and change field types (see next slide)Could name this GEOID Include “ACS” or Rename fieldinstead of ID2. “2010” referring to headings (short source. and meaningful). In this field, use “Find and Replace” to remove unwanted text, leaving only the Tract number, for labeling polygons on a map. 26
  27. 27. Change ID Field Types in Excel In order to join tables in ArcMap, must change the field containing unique tract number (“ID2”) from a number field to a text field. “Format Cells” to Text type will not work! Instead, select a column, then go to “Data > Text to Columns”. Choose “Delimited”, then click “Next”. Choose “Tab”, then click “Next”. Choose “Text”, then click “Finish”. 27
  28. 28. Join Tracts Shapefile With Excel Table Add Tracts polygon shapefile and Excel table to ArcMap. Right-click on the Tracts layer and choose Join. Unique field with Tract numbers in the 2010 Tracts layer is called GEOID10. Field in table to join is 2nd field (name depends on what you named it). Keep matching records. Export to new shapefile. Remove Join. Repeat as needed. 28
  29. 29. Visualize Data Make maps, charts, and tables that emergency response staff will find useful. For map symbology, choose Quantities > Graduated Colors. For Fields > Value, choose category you want to show. For classification, start with default -- Natural Breaks (Jenks). Then click Classify to adjust “Break Values” to ones easily recognized. Get staff feedback on drafts. 29
  30. 30. Resources About Census Data Census Handbook “A Compass for Understanding and Using American Community Survey Data – What State and Local Governments Need to Know”: http://www.census.gov/acs/www/guidance_for_data_users/handbooks/ Short ESRI Slideshow about differences between decennial census and ACS, as well as Margin of Error: http://www.slideshare.net/CCIMTECH/esri-2010-census-and-acs Slideshow produced by Tufts University GIS Center about using Census’s American FactFinder website and downloading data, as well as changing headers and rows of the downloaded CVS tables in Excel: https://wikis.uit.tufts.edu/confluence/display/GISatTufts/Tufts+GIS+TipS heets+ArcGIS10 (under “Census Data”, click link to “Census Tutorial: Downloading and Mapping American FactFinder Data …” 30
  31. 31. What’s Next For This Project? Create a short, targeted report. Check back in a few months for ACS 5-year estimates about population with a disability. Keep data tables, maps and report updated as new ACS data becomes available. Downtown Reno, Normal Early Summer River Flow Photo Source: Truckee River Flood Management Project 31

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