Making Maintenance Manageable Using FME to Maintain FEMA’s National Flood Hazard LayerRob GainesSenior GIS Analyst, Zimmerman Associates (FEMA Ctr) April 18th, 2012
What is the NFHL? FEMA’s National Flood Hazard Layer, part of the National Flood Insurance Program. Nationwide regulatory GIS dataset used to communicate flood risk information.
The Numbers Compiled from 2081 individual community or countywide flood study datasets (and growing). Average 95 county/communities updated per month. 32 spatial layers, 18 lookup tables. Over 85 million records in total.
How is the NFHL Accessed? MapViewer: 100,000 – 200,000 requests per month. KMZ/WMS: 3 – 6 million requests per month. NFHL Extract (via state shapefiles).
Challenges Data produced at community level. Initial QA/QC process not intended for NFHL. Bureaucracy: 10 exceptions to every rule. Far removed from data producers. Inherited systems.
What Is FME Used For? QA/QC of data submissions. Data replication. Extraction. Report generation / tracking. LOMA Point creation.
Basic QA/QC Checks All records have DFIRM_ID value. All required layers are present. No duplicate geometry. Flood hazard lines & areas have valid flood zone values. Effective date information is correct. New data contains all currently effective LOMRs.
Extraction Extract all NFHL records into state-based shapefiles. Generate reports such as panel and LOMR count for each state. QC: Check current extract against prior extract to ensure completeness of layers.
Extraction: QC FME Model Runs through each state extract. Uses ListBuilder to build a list of each state’s layers and check them against previous month’s. Generates Excel report.
LOMA Mapper Daily process which converts flat data with lat/lon attributes to geospatial data in SDE. Replaced custom-developed VB application. Original application: 18+ hour runtime. FME Model: <10 minute runtime.