"This paper focuses on landscape assessment and tries to develop a general model from the results obtained by our research group in several different projects. We have carried out a number of tests in which samples of the public chose the image they preferred from pairs of landscape photographs. Of particular interest are the results coming from the application of a test including pictures representing the main world biomes to a sample of 4900 people from very different cultural and geographical backgrounds (including an Australian sample with European, Oriental and Aboriginal subsamples, several groups in Spain and samples from Venezuela, Puerto Rico, Ecuador and Mexico). There are strong preferences for lush vegetation, running and clear water and mountainous scenery, corraborating previous experiments and hypotheses. These results are relevant for a general model of landscape preferences in an eco_ethological framework of human habitat selection. In order to develop this methodology for it to be useful in specific planning and management problems we have carried out landscape evaluations by the public and experts connected with several applied projects in Spain and Venezuela. These include: landscape cartography and evaluation in the Basque Country, scenic impact assessment on the coast of Alicante, preferences of visitors and local populations for landscapes in protected areas such as the Alcaraz mountains in Spain, Morrocoy national park on the Venezuelan coast and El Avila national park nearby Caracas. In all these cases we have used the landscape photographs pairwise comparison technique to compare the preferences of the public with those of expert panels knowledgeable of the areas. In the Venezuelan studies we also asked the experts to try to predict the public's preferences. From this work we are able to detect the landscape units that act as indicators of what could call "landscape value awareness'. We identify two steps in the process of increased scenic value awareness: first, and the typical reaction of experts, is the preference for natural landscapes and the rejection of impacts; in a further, more advanced, stage comes the appreciation of cultural landscapes particularly relevant in the evaluation and conservation of European landscapes."