Planimetric accuracy of Ikonos 1-m panchromatic image products and their utility for local government GIS basemap applications

A detailed assessment of the planimetric accuracy of high-resolution (1 m) panchromatic Ikonos orthoimage products for three different test sites located in the State of Missouri is presented. The main objective of this study was to evaluate the potential of Ikonos orthoimage products for use as digital image basemaps in local government GIS systems. For maximum utility and adoption in a wide variety of local government planning and management applications, a planimetric accuracy of 3-4 m CE90 is considered nominal. Evaluation of the planimetric accuracies of Ikonos orthoimages acquired under a Space Imaging/NASA Databuy agreement were found to be 1.1 m and 1.7 m CE90 at two different test sites. The terms of the NASA Databuy agreement require a 2 m CE90 planimetric accuracy. Thus, our independent assessment confirms that the Space Imaging products met this NASA Databuy specification. Low precision, low cost georeferenced Ikonos image products (Carterra Geo, 50 m CE90) were orthorectified using third party commercially available software and various custom NAPP DEMs. The planimetric accuracies of the resulting Ikonos orthoimages were found to vary between 2-4 m CE90. In addition, USGS DEMs were also used to orthorectify georeferenced Ikonos image products. The resulting Ikonos orthoimages were found to have planimetric accuracies from 2-7 m CE90. Planimetric accuracies of 2-3 m CE90 can be obtained from georeferenced Ikonos using USGS DEMs with RMS vertical accuracies on the order of 2 m. The approach demonstrated here can be used to deliver up-to-date, cost effective orthoimages from Ikonos Carterra Geo products that yield planimetric accuracies suitable for use as digital image basemaps by local governments.