Alert: Please correct the errors!
The advent of global positioning satellites has increased the accuracy of spatial measurements by orders of magnitude. The luxury of these extremely accurate measurements may induce us to forget some basic cartographic principles of data precision which govern older spatial datasets. A ChevronTexaco study of more than 700 well locations shows that data rounding and truncation, not geodetic datum shifts, are the most likely source of well location errors. The study shows that for this dataset of 764 well locations, 125 wells (16 percent) could be rounded by >1,000 m and 15 wells (2 percent) could be rounded by 10,000 to 56,000 m. Unfortunately, most of the wells with large rounding errors are older, wildcat wells that are critical for regional stratigraphic correlation studies. This method was applied to three independent well location datasets to identify the best-quality well location for each well at a significant cost savings compared to using satellite imagery.