Supplement 1. A C program implementing the algorithm for generating landscapes with spatially structured heterogeneities.

File List 2x1gen.c -- c source code Description This file is the source code for a program (written in the C programming language) that generates rectangular arrays representing landscapes with two habitat types. The habitat types have local spatial clustering, as described in the "Landscapes" section of the paper, and as shown in Fig. 1. The landscape can be output in a couple of different formats. The default behavior is to output an ASCII text file (with a small header) containing a picture of the landscape, with the characters `.' and `X' representing the two habitat types. This is probably most useful when working with landscapes less than approximately 70 x 70 sites. The program can also output the landscape in a raw binary format (with a small header). Finally, it is also capable of storing the landscape in a PGM (Portable Graymap) file. There is a large collection of free utilities written by Jef Poskanzer which manipulate files of this format and convert them to many other image formats (such as GIF); these utilities are included with many distributions of Linux, or you can download them from the ACME Laboratories pbmplus page. You will need some kind of standard ANSI C compiler to compile the code. There are comments at the beginning of the program indicating portability concerns. In particular, the program was developed using "gcc" under the Linux operating system. If you are using a different environment, the calls to the random number generator may need to be modified.