Advancements in Parcel Mapping Tools Part 2
Whether a parcel map is created for an engineering project, land development, valuation, tax assessment, land administration and management, for a subdivision, city, county, or whole country, the tools to create and manage them have dramatically improved. BY GAVIN SCHROCK
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n the past, a key sticking point for surveyors was the lack of solid COGO tools within legacy GIS. “There are still workflows for parcel creation that might involve importing the geometry from CAD or scanning a map, but you can also do the COGO directly in ArcGIS Pro when adding parcels to the Parcel Fabric,” said Tim Hodson, principal product engineer at Esri. “You can do grid-to-ground corrections, etc., and ellipsoid-based directions are also supported, such as true mean bearing, rhumb line, and forward geodetic.” Curves had always been a point of contention. For a while, many GIS folks referred to a variety of geometric elements generically as “arcs,” though not necessarily referring to defined circular arcs (e.g., C3, C5, PC Pt, etc.). “Arcs” were often roughly segmented for display purposes (even CAD does this in its own way). The difference now is that the arc definitions in Esri geodatabases are stored parametrically for circular arcs, elliptical arcs, clothoid spirals, and for Bezier curves. (See graphic.) Adjustments can be needed for the
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A portion of the BLM parcel fabric for California showing sections and protracted block. Source: Bureau of Land Management
process of surveying land boundaries. Few things sent surveyors into a tizzy in the early days of GIS like the term “rubber sheeting.” No, the adjustment tools in Parcel Fabric are not anything of that sort. The adjustment engine is
DynAdjust (pro.arcgis.com/en/proapp/latest/help/data/parcel-editing/ least-squares-parcel-fabric.htm), a relatively new program born, and collaborated on in the GitHub era, taking advantage of advances in processing and