The OneMap Gateway - An SVG/WFS Interface To Distributed Geodata

Gunnar Misund gunnar.misund@hiof.no
Henning Kristiansen henning.kristiansen@hiof.no
Mats Lindh mats.s.lindh@hiof.no
Ostfold University College, Halden, Norway

Extended Abstract

We present an interface to a distributed online world map. The interface, OneMap Gateway, is implemented with SVG and DOM scripting. The communication with the geodata repository is following the OGC Web Feature Server protocol. The WF server is built on top of a distributed storage system based on a GML file structure. The Gateway is part of a larger infrastructure beeing developed in Project OneMap. The main objective of the project is to incrementally build a large, distributed global online map. We demonstrate how the Gateway provides access to the global data from a birds eye perspective to street level details. We also show how the interface dynamically configures itself to accomodate the changing needs of the user during a session combined with the varying availability of data.

Project OneMap

OneMap is functionally comprised by three main components: Repository, Gateway and Clearinghouse. The alpha version has been up and running for a year, and the beta version will be released in June this year.

The Repository is a distributed storage infrastructure. This is basically a (huge) set of GML files structured to efficiently support retrieval and updating of the geodata comprising the world map. The total amount of base data is currently in the magnitude of 50 M points, and is expected to expand to around 500 M points within the next few months. The data is structured in levels of detail to facilitate global overviews as well as street level inspections. The files are distributed redundantly on a set of servers. This facilitates both storage scalability and parallell processing of retrieval queries and updating procedures.

The Gateway is a browser based user interface for quering and retrieval of OneMap data implemented with SVG and scripts. In addition to the SVG view, the users may download the GML version of the response.

One of the main objectives of OneMap is to make it possible to build a huge map in an incremental and uncoordinated manner, with contributions from a wide variety of parties, but still maintain a reasonable level of reliability and quality. The Clearinghouse accepts submissions of new geodata and updates of existing data, and supports peer review processes in order to ensure consistency and quality.

The Gateway UI

There are currently three main tools interfacing the OneMap infrastructure with the users, the Gateway UI, the Submission UI and the GML editor, all SVG based. In the paper we will focus on the Gateway UI.

The Gateway UI is highly configurable. The user have a rich set of tools to query and select information for retrieval. The interface will dynamically configure itself based on the state of the query/retrieval process and the data available according to the selections made by the user.

References

  1. Gunnar Misund and Knut-Erik Johnsen: The One Map Project. In online proceedings from GML Dev Days, Vancouver, July 2002.