Research Methods:

• Using ESRI ArcGIS, geocoded Sanborn Fire Insurance Maps in (.tif) format for Central Phoenix using ESRI basemap imagery and Maricopa County Flood Control District historical aerial photography (1930, 1949, 1979) as references. Despite some temporal mismatch with the Sanborn Map coverage, this imagery helped identify block boundaries for early Phoenix neighborhoods.
• Sanborn Maps for 1900-1949 were available through the ProQuest Digital Sanborn Maps database; Sanborn Maps for 1963 were derived from original scans of a microfilm available through the Arizona State University Libraries Map Collection.
• For each year, clipped a 2002 Maricopa Assessor parcel feature class to the Sanborn Fire Insurance Map coverage for 1915 (roughly Phoenix’s 1915 incorporated boundary). Modified the feature class to include a historical land-use field.
• Using the ArcGIS Editor Toolbar, for each year (working backwards from 1949 and later adding 1963) merged and cut parcel boundaries as delimited by the Sanborn Fire Insurance Maps. Assigned a land-use to each parcel based on classification scheme land-use types (see table). Recorded notes of nonconforming or atypical mixtures of features observed on parcels for future reclassification (as needed).
• For each year, created a secondary land-use field (“Compat_RC”) to generalize land-use into five categories for spatial analysis.
• Repaired parcel geometry and removed spurious “sliver” polygons; removed extraneous fields.