Is ONE Route Good Enough? Using ArcGIS Network Analyst in pipeline alignment optimization By Ahmad M. Salah, Ph.D., GISP, and Denis Atwood, P.E. Pipelines are considered by some to be the most cost efficient and environmentally friendly method for transporting oil, gas, water, and other fluids. The continued growth of municipal areas is increasing the demand for pipelines. However, the high cost of building pipelines and the potential devastation that can be caused by pipeline failures require that these projects be thoroughly planned. Most pipeline alignment tasks involve linking the conduit from an origin point to a destination point. In some applications, more than one origin and destination may be required for the same alignment. Between the origin and destination points, decision makers are always confronted with numerous and a sometimes seemingly infinite number of potential corridors from which to choose. Pipeline alignments have been designed using many methods ranging from filling out simple and subjective forms to employing sophisticated GIS tools. The ArcGIS Network Analyst extension can be used for performing spatial analysis on linear networks. Node-to-node routing, one of the types of analysis that can be performed using Network Analyst, minimizes an objective function (i.e., define the shortest route). Having said that, is producing one “best” route the most 32 ArcUser Spring 2010 www.esri.com