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Global Map

A plan to provide a GIS of the entire Earth is now 60 per cent complete.

Hiromichi Maruyama, from the Geographical Survey Institute in Japan, says that filling in the remaining 40 per cent of the Global Map project will take until 2007. He was speaking at the South East Asia Survey Congress last week (8 SEASC; Brunei Darussalam, 22-25 November).

Maruyama is also secretary general of the International Steering Committee for Global Map, the organisation created to further the preparation of the world map.

Global Map is a project to describe the entire land surface of the globe using eight layers at 1:1 million scale.

The plan was hatched more than a decade ago at the United Nations' Environmental Summit held in Rio de Janiero in 1992, as a response to Agenda 21.

Agenda 21 was a call for better mapping and monitoring of the global environment. It has been the justification for an entire generation of spacecraft, which have produced a huge amount of high-quality data. The efficiency of the use of that data has been more problematic however.

Global Map is organised as a series of layers. The layers include vectors showing population centres, rivers and their catchments, administrative boundaries, elevation and transport routes such as roads and railway lines. They also include three rasters, showing land use, land cover and vegetation.

The data produced is available through the organisation's website iscgm.org, or on CD.

Australia's Geological Survey, later Geoscience Australia, was an early, enthusiastic supporter of the concept. GA was able to take its existing 1:1 million map coverage and convert it to Global Map format with very little effort.

The justification of the Global Mapping Project is to provide materials for better understanding of global environmental problems, thus supporting sustainable development and mitigating natural disasters.

As the database nears completion, attention is inevitably turning from the creation of the database to its maintenance. In particular, Maruyama is urging a plan to update land use, land cover and vegetation rasters on a five-year cycle.

Under his plan, rasters would be created from satellite imagery and ground truthed locally.

However, it is not clear why updating the map will be a quicker process than its creation, which will have taken a decade if current objectives are fulfilled.

It is clearly difficult for the ISCGM to influence the speed with which Global Map is being created. Maruyama stressed that the role of the ISCGM is not to build datasets, but to organise the production of those datasets by national mapping organisations.

However many of these national mapping organisations are hopelessly under-resourced. They will not be able to make much contribution unless they are aided in the process.