James W. Sewall

Photogrammetric Mapping

Since the 1950s, Sewall has mapped literally thousands of towns, cities, and counties for government, utilities, and the forest industry. To compile planimetric landbase mapping, capture elevation data, and create digital terrain models (DTMs), our certified photogrammetrists use softcopy stereo-photogrammetric methods, controlling the quality of stereo imagery with 3D contour superimposition, iterative contour refinement through DTM enhancements, and independent compiler stereomodel inspection.

This mapping provides an accurate landbase for utilities infrastructure, natural resource, volumetric, addressing, tax parcels, and cemetery mapping and for project-related, department-specific, and enterprise-wide GIS. Deliverables are in multiple AutoCAD, ArcInfo, and ArcGIS formats to meet specific client needs.