Abstract

Updating FEMA's National Flood Hazard Layer
Track: Federal Applications and Enterprise Management
Authors: Thomas Tri

Changes in federal specifications require updating National databases in the most efficient manner possible while ensuring the data quality remains high. FEMA's National Flood Hazard Layer (NFHL) update required new tools and quality controls measures to be implemented into Atkins' FloodMap Desktop ArcGIS extension. This tool works with personal, file and ArcSDE Enterprise databases, utilizing ESRI queries to extract data and write it into another database. In order to perform quality control on the database conversion, a rules-based Python script was developed. The rules are stored in Excel where a non-programmer can define the QC checks to be validated. The script uses simple row counts as well as a SQL Server based ArcSDE instance to leverage the CHECKSUM and HASH functions to validate attribute conversions regardless of data type. This presentation will focus on some of the techniques and lessons learned to increase the efficiency and quality of the conversion.