Numerical inverse transformation for map projections

In cartography map projections are used to transform geographical coordinates to plane coordinates. This is called forward transformation. For many geographic information system (GIS) applications paper maps are digitised, and so captured data are integrated into another data set. In this situation plane coordinates should be transformed into geographical coordinates. This process is called inverse transformation. This paper discusses two numerical methods for inverse transformation, if the projection or projection parameters of the digitised paper map are not exactly known. (C) 2003 Elsevier Ltd. All rights reserved.