¿Cómo varía UN fenómeno a través del espacio geográfico? Esta es la pregunta que ayuda a resolver la autocorrelación espacial. En este editorial se presenta una breve introducción al concepto de autocorrelación espacial y a los métodos de análisis usados para clasificar y cuantificar el comportamiento de un fenómeno a través del espacio. Además, se presenta una contextualización histórica sobre su origen y desarrollo, y una serie de elementos que se espera ayude a aclarar las posibles confusiones entre la correlación y  autocorrelación espacial. Las descripciones y conceptos expuestos no son desarrollados con rigurosidad matemática ni detallando la formalización de cada método, por el contrario, se presentan como discusión conceptual que describe los fundamentos y detalles que se consideran necesarios para conocer y comprender la base de los principales métodos  estadísticos espaciales hasta ahora desarrollados para analizar la variación de los fenómenos geográficos. El objetivo de estas notas es que sirvan de soporte para cursos introductorios de análisis espacial.

The main achievements of spatio-temporal modelling in the field of Geographic Information Science that spans over the past three decades are surveyed. This article offers an overview of: (i) the origins and history of Temporal Geographic Information Systems (T-GIS); (ii) relevant spatio-temporal data models proposed; (iii) the evolution of spatio-temporal modelling trends; and (iv) an analysis of the future trends and developments in T-GIS. It also presents some current theories and concepts that have emerged from the research performed, as well as a summary of the current progress and the upcoming challenges and potential research directions for T-GIS. One relevant result of this survey is the proposed taxonomy of spatiotemporal modelling trends, which classifies 186 modelling proposals surveyed from more than 1450 articles. CCS Concepts: • Information systems~Geographic information systems • Information systems~Temporal data • Computing methodologies~Spatial and physical reasoning • Computing methodologies~Temporal reasoning Additional Key Words and Phrases: spatio-temporal models; survey; literature review; temporal GIS; time geography; spatio-temporal databases; temporal models.

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This paper presents the results of simulating the conditions of absorption of natural radionuclides (uranium-238, thorium-232, potassium-40) in different environment media (water and quartz sand) to assess the effect of the shielding properties of environmental components on the intensity of external radiation exposure to the benthic biota. The source of radiation was the lower Tremadocian Dictyonema shale, which formed the bottom of the Baltic Paleobasin. Water and quartz sand, which was gradually deposited on the roof of the Dictyonema shale, were used in the simulation as media (materials) absorbing the primary radiation. The manuscript shows an experiment conducted in full-scale conditions considering a single exposure of a section of Ordovician rocks that includes highly radioactive Dictyonema shale. This is a small area, but the simulation results are also valid for larger areas as the Baltic Paleobasin. During the late Tremadocian -Floian, along with transgression, benthic biota began to emerge. The experiment shows quantitatively what dosage this biota could have experienced over tens and hundreds of thousands of years, until the Dictyonema shale was covered with a sufficiently thick layer of water-flooded sediments. Experimental data show that the presence of a 10 cm thick layer of water reaches absorption of 40 % of the integral flux of all gamma lines of natural radionuclides (NRN), and in a moist quartz sand layer of the same thickness the absorption value does not exceed 50 %. Thus, despite the screening effect of the environment, the benthic biota of Baltoscandia in the Early Ordovician could have been under significant radiation exposure for millennia. The main value of the experiment is that it was performed in situ, and exclusively natural media were used as modelling elements.