This article presents an improved parallel Raster Processing Library -pRPL version 2.0. Since the release of version 1.0, a series of modifications has been made in pRPL to improve its usability, flexibility, and performance. While retaining some of the key features of pRPL, the new version has gained several new features: (1) a new DataManager class has been added for integrated data management, and to facilitate data decomposition, assignment mapping, data distribution, Transition execution, and load-balancing; (2) a GDAL-based raster data I/O mechanism has been added to support various geospatial raster data formats, and provide centralized and pseudo parallel I/O modes; and (3) a static load-balancing mode and a dynamic load-balancing mode using the task-farming technique are provided. A parallel zonal statistics tool and a parallel Cellular Automata model were developed to demonstrate the usability and performance of pRPL 2.0. The experiments using the California datasets showed that the performance altered when different pRPL options (i.e. load-balancing mode, I/O mode and writer mode) were used for different algorithms, datasets, and varying numbers of processes.

Access control of spatial information workflow is mainly achieved by access authorization that only permit user to do operation just when they satisfy all constrain conditions. RBAC model also can't be applied flexibly. It can't express complicated workflow access constrain, especially can't express constrain between roles. It also can't deal with the correlativity between spatial information resources. Furthermore, it can't combine security strategy of spatial information into workflow. How to depict and manage relation between spatial information resource and role uniformly is the most important and universal demand of spatial information workflow system. Therefore, this paper tries to introduce ontology into authorization management in spatial information workflow system, and puts forward an ontology-based authorization management model to depict and manage authorization-related information uniformly so as to build a security system flexibly and conveniently. It also designs a user resource authentication algorithm based on this model which has been applied successfully in the new generation GIS platform--MapGIS 7.0.

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