Accessing GIS data via the WWW: Information Provision to the Ecotourist

S.E.P. Pollitt & S.D. Kirkby,
National Key Centre for Social Applications of GIS, University of Adelaide
Email: sepollit@gisca.adelaide.edu.au and skirkby@gisca.adelaide.edu.au
Phone: +61 8 303 3900 Fax: +61 8 303 3498

Keywords: WWW, GIS, Online GIS, Ecotourism

Introduction

This poster describes the design and implementation of a WWW interface to a Geographic Information System (GIS), applied to the domain of Ecotourism.

Background

Ecotourism is a growing industry in which people enjoy a learning experience through diverse activities, while safeguarding the natural environment. To capture a share of this market, it is essential for governments and private operators alike to provide strategic spatial and associated attribute information regarding accessible features and facilities to tourists prior to departure. The WWW is the ideal vehicle for the construction of such a system.

System Model

To provide information to users over the WWW, we designed and constructed an interface to a GIS (namely Arc/Info) having 3 main features:

1. Display: the manipulation, zooming, panning and selection of GIS database features.
2. Hot Links: enabling the map to function as a regular imagemap taking the user directly to associated (standard) HTML pages.
3. Interrogate: allowing the GIS database to be interrogated.

To ensure a simple and user-friendly Graphical User Interface (GUI), all these functions were made available on the same map, on the one web page.

A PERL script was written creating a HTML form with the above functions interpreting the user's actions. The script decides which function the user has chosen, then acts as an interface to the GIS to perform the operation and returning the results to the user.

The system is summarised in Figure 1, with the 3 major function paths through the script given by the numbers (1), (2) and (3).

The Visual Appearance

The appearance of the interface has been designed in conjunction with a number of experts in the field of human-computer interaction to ensure the system is both user-friendly and powerful. To this end, the main parts of the interface (map output and feature selection) have been designed to fit on a single browser page (on a UNIX based workstation).

The core of the interface is shown in Figure 2.

The action to perform is selected using one of the three buttons from the top of the page. In the case of Zoom, the magnification level is selected from the drop down box.
The Redraw button redraws the current map extents, but accounts for any changes in the feature selection.
The Reset button returns to the original map extents, but keeps the currently selected features.
The two maps (Spatial Location and Detail) are used in tandem to move around and interrogate the GIS. The Spatial Location Map is used to move large distances and to identify the real-world location of the displayed Detail Map (the red hashed area). The Detail Map allows panning and zooming, interrogating and hot-link functions to be performed.
The Scale Bars underneath the two maps provide the accurate scale for each map.
The Feature Selection table allows the user to select GIS coverages (features) to display, by selecting the corresponding check box. This table also acts as the key, with the small coloured boxes to the left of each feature indicating the colour displayed on the map.

The Implementation

At the heart of the system is a simple resolution engine (RE) that translates between displayed points (pixel co-ordinates) to the GIS units (AMG co-ordinates). All manipulation is performed by the system in AMG co-ordinates, allowing easy interaction with the GIS.

1) Map Manipulation function
When a zoom, pan or feature selection function is used, the following sequence of events occurs:
The resolution engine translates the "click point" to AMG co-ordinates. Any zooming is then performed to get the new map extents, using the point as the center of the map extent box.
The selected GIS features, along with the map extents, are written to an Arc Macro Language (AML) script which is passed to the GIS.
The GIS generates an output map which is converted to a GIF file and passed back to the user in a new form (ready for the next submission).

2) Hot Links function
A list of all hot-linked regions and their corresponding links is stored in the script, with the regions being specified in AMG co-ordinates. Regions are only available for Parks and Towns.
The "click point" is translated to AMG co-ordinates using the resolution engine and then matched sequentially with the hot-linked region.
The first region that matches the point is used to jump to the corresponding HTML page.
If the point doesn't fall within any of the regions, no action is performed.

3) Interrogate function
The "click point" is resolved to AMG co-ordinates using the resolution engine.
An AML is generated interrogating the selected layers from within the GIS.
The GIS is executed producing an output text file. This file is parsed and a report drawn up and added to the form.

Conclusion

As the ecotourism industry expands world-wide, the provision of information stored in changing GIS databases to a distributed audience becomes critical. This system provides a generic framework for this distribution to occur, as well as raising the possibility of transferring the principles to a different domain.

The page may be accessed from the GISCA CGI-BIN site.

Alternatively, the whole system (including background domain information) can be accessed here.

Copyright

Simon Pollitt, Steve Kirkby © 1996. The authors assigns to Southern Cross University and other educational and non-profit institutions a non-exclusive licence to use this document for personal use and in courses of instruction provided that the article is used in full and this copyright statement is reproduced. The authors also grants a non-exclusive licence to Southern Cross University to publish this document in full on the World Wide Web and on CD-ROM, and for the document to be published on mirrors on the World Wide Web. Any other usage is prohibited without the express permission of the author.