ISOPAQ, a MATLAB program for stratigraphic and isopach mapping: example application to the French Bajocian (Jurassic) sediments
The three-dimensional reconstruction of basin sediments has become a major topic in earth sciences and is now a necessary step for modeling and understanding the depositional context of sediments. Because data are generally scattered, the construction of any irregular, continuous surface involves the interpolation of a large number of points over a regular grid. However, interpolation is a highly technical specialty that is still somewhat of a black art for most people. The lack of multi-platform contouring software that is easy to use, fast and automatic, without numerous abstruse parameters, motivated the programming of a software, called ISOPAQ. This program is an interactive desktop tool for spatial analysis, interpolation and display (location, contour and surface mapping) of earth science data, especially stratigraphic data. It handles four-dimensional data sets, where the dimensions are usually longitude, latitude, thickness and time, stored in a single text file. The program uses functions written for the MATLAB(R) software. Data are managed by the means of a user-friendly graphical interface, which allows the user to interpolate and generate maps for stratigraphic analyses. This program can process and compare several interpolation methods (nearest neighbor, linear and cubic triangulations, inverse distance and surface splines) and some stratigraphic treatments, such as the decompaction of sediments. Moreover, the window interface helps the user to easily change some parameters like coordinates, grid cell size, and equidistance of contour lines and scale between files. Primarily developed for non-specialists of interpolation thanks to the graphical user interface, practitioners can also easily append the program with their own functions, since it is written in MATLAB open language. As an example, the program is applied here to the Bajocian stratigraphic sequences of eastern France. (C) 2003 Elsevier Ltd. All rights reserved.
interpolation contour and surface mapping decompaction graphical user interface sequence stratigraphy