13 research outputs found
Multiagent System for Image Mining
The overdone growth, wide availability, and demands for remote sensing databases combined with human limits to analyze such huge datasets lead to a need to investigate tools, techniques, methodologies, and theories capable of assisting humans at extracting knowledge. Image mining arises as a solution to extract implicit knowledge intelligently and semiautomatically or other patterns not explicitly stored in the huge image databases. However, spatial databases are among the ones with the fastest growth due to the volume of spatial information produced many times a day, demanding the investigation of other means for knowledge extraction. Multiagent systems are composed of multiple computing elements known as agents that interact to pursuit their goals. Agents have been used to explore information in the distributed, open, large, and heterogeneous platforms. Agent mining is a potential technology that studies ways of interaction and integration between data mining and agents. This area brought advances to the technologies involved such as theories, methodologies, and solutions to solve relevant issues more precisely, accurately and faster. AgentGeo is evidence of this, a multiagent system of satellite image mining that, promotes advances in the state of the art of agent mining, since it relevant functions to extract knowledge from spatial databases
A novel approach to updating municipal tax parcel impervious surface calculations
Accurate impervious surface calculations are important to many municipalities due to the high volumes of surface rainwater runoff caused by high impervious surface density. Municipalities must deal with this runoff through the establishment and maintenance of drainage facilities. To help offset the added cost of these facilities, many municipalities impose taxes and fees on privately owned impervious surfaces such as homes, driveways, and patios. Currently, in order for a city like Harrisonburg to calculate tax parcel impervious surface density, aerial images must be manually digitized or mapped using computer-based classification techniques using predictive models. These methods of impervious surface calculations can cost municipalities thousands of dollars and/or hundreds of person hours. The purpose of this project is to devise and test a novel procedure for updating municipal tax parcel impervious surface calculations in an effort to help reduce the time and cost currently required to perform these updates. The procedure that was devised establishes a statistical relationship between current aerial imagery attributes (such as mean pixel value, texture, and homogeneity) and past impervious surface calculations. Tax parcels where actual impervious surface density differed greatly from the model’s expected density were flagged to be looked at manually for possible update. This procedure is useful to municipalities because it cuts costs and labor time compared to other methods currently available. Although this project is a case study for the City of Harrisonburg, this procedure could potentially be tailored to other municipalities that have access to high resolution aerial imagery and pre-existing impervious surface maps
FRAGILIDADE AMBIENTAL E PERDAS DE SOLO EM UMA MICROBACIA HIDROGRÁFICA NO PLANALTO DOS GUIMARÃES EM MATO GROSSO
A ocupação de áreas de Cerrado para a expansão das atividades agropecuárias levou à ocupação de solos sem considerar a sua aptidão natural. Em geral, esses solos apresentam elevada fragilidade. Com a intenção de contribuir com estudos que levam a compreender os processos erosivos e identificam os riscos ambientais, este trabalho apresenta cartas temáticas que demonstram a fragilidade potencial e emergente na bacia hidrográfica dos córregos Amaral e Brilhante, em Jaciara - MT - Brasil. Os materiais utilizados foram: mapa de solos na escala 1:50.000, dados altimétricos da missão espacial denominada Shuttle Radar Topography Mission; imagens de satélites e dados pluviométricos. A metodologia permite, por meio de geoprocessamento, determinar e mapear a fragilidade ambiental das unidades ecodinâmicas através de cruzamento e análise de cartas com informações de cobertura vegetal e uso da terra, do relevo, erodibilidade dos solos e erosividade das chuvas. Os resultados mostram o predomínio de áreas de média e alta fragilidade potencial com elevadas perdas de solos, ou seja, predomina no local, terrenos com problemas complexos de conservação. Os resultados indicam também que as técnicas de geoprocessamento proporcionam inúmeros recursos de análise espacial, confirmando-se como ferramentas úteis na determinação da fragilidade ambiental de bacias hidrográficas
Micro-topography associated to forest edges
Forest edges are often defined as the discontinuity between the forest habitat and an adjacent open habitat, thus they are based on a clear difference in the structure of the dominant vegetation. However, beside this very general definition, in the field we can observe a large diversity of edges, with often different kinds of micro-topography features: bank, ditch, stone wall, path, etc. As these elements are rather common in many temperate forest edges, it seems important to start to characterize them more clearly and with consistency. From a set of observations in south-western France, we build a first typology of the micro-topographic elements associated to forest edges.
For each of them we describe the process, natural or human induced, at their origin, and according to the literature available, we identify some of their key ecological roles. Banks, generated by the differential erosion between forest and crops along slopes, are especially analyzed since they are the most common micro-topographic element in our region. It offers many micro-habitat conditions in the soil used by a wide range of species, notably by several bee species. More research is required to study in details the importance of such micro-topographic elements