The paper focuses on the field of ontology evaluation and visualization. Ontologies represent the essential technology for the development of the Semantic web applications. This technology has been proven to be useful in a range of applications for data manipulation and administration. The paper introduces an ontology visualization approach based on descriptive vectors. It offers the design of descriptive vectors representation for an ontology domain and also the algorithm design for generation of the descriptive vectors. This approach offers quick overview of the given ontologies content. In addition, this work presents the design of methods for comparison and evaluation of various ontologies based on descriptive vectors. Moreover, it introduces a method for ontology placing in the context within an ontological space (the map). Finally, a method for administration of user navigation in the ontological space is presented.