{'fraction_non_alphanumeric': 0.019128586609989374, 'fraction_numerical': 0.0, 'mean_word_length': 5.116883116883117, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
SCALE-BASED SIMULATION OF TOPOGRAPHY

A model of natural terrain is proposed, which describes topography as the summation of scale-dependent periodic spatial structure, and scale-independent fractional noise. These two elements can be varied, and appear related to each other by the sampling theorem and the scale at which the model is applied. The scale-dependent component of the model can be calibrated for any given landscape using Fourier analysis, as can the scale-independent component by measurement of the fractal dimension of a specific piece of terrain. The model is invertible, allowing simulation of terrain with specific surface characteristics. This paper develops the model mathematically, gives a description of the advantages and disad vantages of the model, shows examples of the use of the model for terrain simulation using a test data set, and discusses the cartographic uses of the model in automated mapping sys tems.