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Track: Defense and Intelligence

David Fong
Esri
380 New York Street
Redlands, CA 92373


Telephone: 909-793-2853
Fax:
E-mail: dfong@Esri.com



Joe Metzidis, Satish Malipeddi

The VPF Viewer Extension for ArcView  Paper Text

Defining Issue: Vector Product Format (VPF) is a military standard for vector-based digital map products produced by the U.S. Department of Defense (DOD). It has been adopted as part of DIGEST in the form of Vector Relational Format (VRF), so VPF can be considered to be an international standard as well. Over the past five years, the National Imagery and Mapping Agency (NIMA, formerly DMA) has produced an increasing number of digital map products in VPF format. The Digital Chart of the World (DCW) was the first such product in 1992. Since then NIMA has developed and produced DNC, VMAP, UVMAP, WVS, VITD, and DTOP in VPF. In order to utilize these new sources of data, GIS software must be able to accept the VPF data. Esri's initial solution was to develop conversion tools in ArcInfo to import/export VPF data into ArcInfo coverages. This was satisfactory if one had ArcInfo, but it was inefficient if one merely wanted to query a VPF database. GIS Solution: Esri has developed an extension to ArcView that will directly read and display VPF data without having to convert the data into another format. With this extension, VPF data can be treated as any other compatible ArcView data source. VPF themes can be created and queried and used in conjunction with themes from other sources (both raster and vector). Methodology: The methodology used to implement the ArcView VpfViewer was very simple. First we asked ourselves, what kind of ArcView functionality does a user of VPF data desire? We answered this question with the following approach. Software developers talk directly to ArcView users and those knowledgeable about VPF data sets. In essence, software development is teamed with applications. Second, we asked, given ArcView software's architecture, what is the best way to implement the desired VPF functionality. ArcView software's design and architecture are rooted using basic principles of object-oriented design and analysis. ArcView supports an object-oriented scripting language named Avenue. Description of public classes can be found using ArcView/Avenue on-line help. The basic building block for thematic mapping and table query is the feature theme and the feature table. The ArcView VpfViewer is essentially a subclass implementation of the feature theme and feature table. Special support was added to make the VpfViewer behave somewhat like ArcView software's librarian to add support for tiling and area of interest.



Copyright 1997 Environmental Systems Research Institute