Rubber Sheeting Corridors - "unstable" calibration

Most Rubber Sheeting algorithm are based on Projective Geometry or use Delauney Triangulation to create a TIN (triangulated irregular network). The truth is, most rubber sheeting tools don't work in all situations. Here's an example of what many professional mapmakers already know, most rubber sheet tools rarely produces the results you would expect in Corridor Applications (where the calibration points are arranged along a single axis to produce so called "unstable" calibration.

This example simulates the rubber sheeting of a corridor design sheet such as might be used in a pipeline or fiber optic cable application.

The corridor feature is simulated by the Red line. Surrounding features are simulated by the blue lines above and below. The dashed green line represents the true location of our corridor (it might represent a pipeline, a Fiber Optic line, or a power line).

Using a typical commercial Rubber Sheeter (not ADJUST), we pick 20 pairs of calibration points between the corridor and it's target below.

Instantly we recognize that the corridor does not match the target. In some cases the instructions suggest that you "try picking the points in a different order".

One support person actually said "play around with the pick order to find the right combination". So we try different pick orders. Adjust is the ONLY rubber sheeting tool that guarantees a Zero Error at every calibration point without regard to the number of points, the order those points are picked in or the "stability" of the point pattern.

We have accumulated dozens of testimonials for Adjust since it's introduction in 1992, including one from South Korea that indicated Adjust had been blessed as the "official" rubber sheeting tool for South Korea. The one I chose to include here is the most recent arrival from a long time customer.

John Baer, Survey Project Coordinator, Land Survey Division,
Department of Transportation, Washington County Minnesota

"Faced with finding a way to transform several tiles of our county GIS basemap to a slightly different local coordinate system without redrawing any linework, we turned to TCI's ADJUST program. ADJUST did the job quickly, saving us hundreds of hours, without compromising our accuracy standards."