Close
 Security code
Close

Breaking News with Geoman Subscription

 Security code
Close

Blog Newletter Subscription



 Security code

Centerlines: A Digital Workflow from Plat to Pavement Management

by Mike on March 12, 2015

80% of the information in the world is tied to an address, and in most locales, that address derives from a street, or more particularly, a street centerline. Addresses are a calculation of the distance along a road or street that a house, building, or other facility occupies.  Typically, the address ranges are graduated from a central origin, and are divided so that odd numbers fall on the right side of the road and even numbers fall on the left as the range value increases.
 
In the world of land development, most street centerlines are defined with rules of geometry to assist in their field layout and construction, and these days that means they are generated in CADD (computer-aided design and drafting) files.  This applies to all roads, from super-elevated, multi-lane freeways to quiet residential streets.
 
If we are crafty and thinking ahead, that CADD geometry can be captured and used in automated systems again and again in ways that transcend the design and construction layout phase, all the way through the life-long maintenance of the road. And in that crafty forethought there are cost-savings and efficiencies that can even improve safety and convenience of citizens’ daily lives.
 
Consider the lifecycle of an “intelligent” street centerline:
 
It starts as geometry on the preliminary plat, coded with a street name and addressing ranges.  As the preliminary plat is subdivided into final plats in sections, the original proposed geometry is split, possibly adjusted geometrically, and used to calculate final lot addresses.  The addressing software in a GIS (Geographic Information System) uses the length of the geometry to calculate the applied range, and even-odd offsets of drives, signs, home sites, and more. When the streets are as-built, they are coded with commission dates and maintenance data.  To support 911 and routing apps, additional geometry may be created to match traffic patterns (cul-de-sacs, directionality, multiple lanes).  Computer-Aided Dispatch (CAD) systems use this information to route emergency responders. 
 
Finally, as maintenance proceeds, future projects may further subdivide the geometry, and additional records applied on a calendar basis.  And all of that data may also be joined spatially to the polygonal areas of the pavement, or joined by matching attributes or coincident topology to separate point, linear or polygonal geometric features for curbs, walks, street lights, signs, ramps, bike paths, lanes, and trails, and more. Once again, Computer-Aided Facility Management (CAFM) systems can use the geometry to calculate costs for maintenance and repairs, in an optimized fashion that ensures the public investment in roads and labor is as efficient and cost-effective as possible over the long run: it is much less expensive to maintain a road at a quality level than it is to allow deterioration to the point that removal and replacement have to occur.
 
Far too often, municipalities tend to pay for the generation and re-creation of the street centerline geometry and all the attribution data that accompanies it over the many phases of its lifecycle over and over again – sometimes requiring additional trips to the field or even aerial surveys to collect and maintain the data.  This is why forethought paired with a clever database design can save municipalities thousands and thousands of dollars over the years – all it takes is a good balance of insight on the CADD – GIS – CAD - CAFM workflow.