GeohashTile: Vector Geographic Data Display Method Based on Geohash

© 2020 MDPI AG. All rights reserved. In the development of geographic information-based applications for mobile devices, achieving better access speed and visual effects is the main research aim. In this paper, we propose a new geographic data display method based on Geohash, namely GeohashTile, to improve the performance of traditional geographic data display methods in data indexing, data compression, and the projection of different granularities. First, we use the Geohash encoding system to represent coordinates, as well as to partition and index large-scale geographic data. The data compression and tile encoding is accomplished by Geohash. Second, to realize a direct conversion between Geohash and screen-pixel coordinates, we adopt the relative position projection method. Finally, we improve the calculation and rendering efficiency by using the intermediate result caching method. To evaluate the GeohashTile method, we have implemented the client and the server of the GeohashTile system, which is also evaluated in a real-world environment. The results show that Geohash encoding can accurately represent latitude and longitude coordinates in vector maps, while the GeohashTile framework has obvious advantages when requesting data volume and average load time compared to the state-of-the-art GeoTile system

Management of spatial data for visualization on mobile devices

Vector-based mapping is emerging as a preferred format in Location-based Services(LBS), because it can deliver an up-to-date and interactive map visualization. The Progressive Transmission(PT) technique has been developed to enable the ecient transmission of vector data over the internet by delivering various incremental levels of detail(LoD). However, it is still challenging to apply this technique in a mobile context due to many inherent limitations of mobile devices, such as small screen size, slow processors and limited memory. Taking account of these limitations, PT has been extended by developing a framework of ecient data management for the visualization of spatial data on mobile devices. A data generalization framework is proposed and implemented in a software application. This application can signicantly reduce the volume of data for transmission and enable quick access to a simplied version of data while preserving appropriate visualization quality. Using volunteered geographic information as a case-study, the framework shows exibility in delivering up-to-date spatial information from dynamic data sources. Three models of PT are designed and implemented to transmit the additional LoD renements: a full scale PT as an inverse of generalisation, a viewdependent PT, and a heuristic optimised view-dependent PT. These models are evaluated with user trials and application examples. The heuristic optimised view-dependent PT has shown a signicant enhancement over the traditional PT in terms of bandwidth-saving and smoothness of transitions. A parallel data management strategy associated with three corresponding algorithms has been developed to handle LoD spatial data on mobile clients. This strategy enables the map rendering to be performed in parallel with a process which retrieves the data for the next map location the user will require. A viewdependent approach has been integrated to monitor the volume of each LoD for visible area. The demonstration of a exible rendering style shows its potential use in visualizing dynamic geoprocessed data. Future work may extend this to integrate topological constraints and semantic constraints for enhancing the vector map visualization

Bioinformática aplicada à unificação dos bancos de histocompatibilidade dos laboratórios de imunogenética do Hospital de Clínicas e Genética Molecular Humana da UFPR

Resumo: O Laboratório de Imunogenética do Hospital das Clínicas (LIHC) da Universidade Federal do Paraná (UFPR) dispõe de um grande volume de dados de tipagens HLA de familiares de pacientes, que foram cadastrados em um banco com o objetivo de serem doadores de medula. Por esse motivo, é desejável que este banco de doadores teoricamente neutro e não viciado possa ser utilizado em estudos de genética de populações como banco de controle. O Laboratório de Genética Molecular Humana (LGMH) da UFPR possui um banco de dados de indivíduos do Paraná que é utilizado como controle. Este trabalho teve como propósito principal a unificação dos bancos de dados do LIHC com o banco de dados do LGMH, com o objetivo secundário de determinar se o banco do LIHC pode ser empregado como banco controle(grupo de indivíduos). Foram criadas páginas e scripts para unificação, classificação e limpeza dos dados. Foi utilizado banco de dados PostgreSQL e linguagem de programação PHP. Um perfil dos bancos foi traçado através do programa PyPop e Arlequin. Descobriu-se que o banco do LIHC pode ser usado como controle em virtude da análise realizada. Porém a análise demonstrou que houve diferença estatística somente para três especificidades distintas das 43 observada para a etnia branca e nenhuma para a etnia mulata. Este resultado foi obtido para o cálculo de frequências comparativas do genes HLA-DRB1 em comparativo com o banco controle do LGMH. Por fim, os scripts e páginas criados para separação e organização dos dados permitem a realização de pesquisas em tempo menor, bem como a garantia de dados padronizados no futuro