Address geocoding and LRS dynamic segmentation (dynseg) are two commonly used processes that yield geospatial coordinates for plotting and spatially analysis. To me, the key difference between the two lies not in the structure of their input sources, but their ability to pass the following tests:
- The Understandability Test
Each input source component has its semantic meaning in identifying the address location interpretable by humans.
- The Stability Test
Input source should not require to change when the underlying geodetic network is redefined or routes are updated.
Address geocoding passes the two tests handily. With 2033 E Warner Rd, Tempe, AZ 85284, for instance, you can understand and even “visualize” the location without the aid of a map if you are familiar with the road addressing network in the area. And the address does NOT change simply because we may use different geodetic system (NAD 83 or WGS84) or a coordinate system.
In contrast, an event entry such as SR 001 at measure 130,200 ft, in the route-measure format required by LRS dynseg, is not conducive for human consumption. Any idea of the location 130,200 feet from the beginning of SR 001? Besides, the event measure is dependent on the underlying route definition, which is subject to changes, more frequent than geodetic system changes.
Fortunately, to pass the two tests, all it takes is to change LRS event location notation from measure-based to reference-based, such as SR 001 pass D Street by 0.3 mile.
Better yet, LRS geocoding is not wishful thinking with a route reference layer as described in my recent article Building the Magic Layer – Secrete Sauce Unvailed.
As GIS-T technologists, we will do our community a great service by switching LRS dynseg to LRS geocoding.