The Gi4DM held in Italy from 2nd to 4th February again demonstrated the crucial role of geo-information in assessing disaster damage. At the forefront of discussions was the devastating earthquake that hit Haiti on 12th January 2010. Timely triggering, and absence of cloud cover, allowed GeoEye to acquire very high-resolution satellite imagery (50cm) over the main affected areas within a few hours of the disaster, and Google made the imagery immediately and universally accessible, overcoming licensing issues that may interfere with rapid response. Aerial imagery at ground-sample distance (GSD) up to 15cm followed a few days later. The eager efforts of satellite-data providers and space agencies resulted in national coverage with optical and radar data immediately disseminated through Google: a crucial turning point.

High-resolution data captured over a large area had to be interpreted under harsh time constraints to obtain reliable damage-assessment maps, which became available within a few days. Procedures for fully automatic interpretation of imagery are as yet non- existent, so mapping collapsed/damaged buildings, spontaneous camps and road accessibility required manual interpretation by a large crew of volunteers. Essential for success was good management and effective co-ordination of large crews pieced together from individuals with a variety of backgrounds. Interpretation of the same area twice means intolerable time wasting; harmonisation of procedures is essential to guarantee that all operators extract the same type of information.

Crucial too is availability of reference geodata which is up to date and detailed enough to act as backdrop for damage-assessment maps. Lack of such demonstrates the importance of participatory mapping through media such as OpenStreetMap or Google Map Maker. A participatory approach allowed large areas of Haiti to be mapped within a few days of the catastrophe; accuracy was not the highest priority given ‘any information is better than none'.

Integration in a Spatial Data Infrastructure (SDI) such as the UN-SDI demands a defining of how data should be shared on-the-fly and in which data models. How should information be represented on maps to best serve the needs of relief workers? Common guidelines had to be developed, shared and regularly adjusted according to feedback from emergency teams.
The response to the Haiti disaster demonstrated the overriding need to establish good co-ordination bodies equipped with proper support tools.