GEOWIKI databases

Contribute to the development of new databases

GEOWIKI is essentially a means of many people contributing to the development of a large database (sometimes called crowd-sourcing). On this page are a number of databases that are being developed using a Google Earth based GEOWIKI and which, after quality control, will be used to answer some important environmental questions and will also be made available for download in common GIS formats.


Dams database geowiki

DAMS database Version 1

Contact Mark Mulligan . Click here to access and contribute to the dams database geowiki (now superseded by

Click here to access dams in the area of the Sichuan province Earthquake.

This is a global database of dams developed by digitising visible dams in Google Earth and naming them. The database has been developed as part of the pantropical hydrology research at King's College London ( . We have used it to examine hydrological inputs to these dams and the impacts of climate and land use change. It is made available to the user community in raw and unfinished form in the hope that others will contribute to its development so that it will grow in use and utility. A geowiki is provided for this purpose.

What are we trying to do?

Build a database of the world's dams


Dams are critical to water supply and energy generation in many countries yet :

(a) there is no definitive spatial database of dams

(b) we cannot measure or model the impact of land use and climate change on water supply to dams without such a database

(c) dams are the point at which intangible water based environmental services become tangible and they are this potentially critical in financing upstream watershed management and conservation

How can you help?

Spend a few hours looking closely at an area of your choice in Google Earth and use the built-in Geowiki to digitise the dams for that area.

Thank you for contributing.

Large tree crowns in the Amazon

Large crowns database Version 1

Large crowns geowiki

Contact Mark Mulligan . Click here to access.

This is an Amazon-wide database of large (>40m diameter) crowns developed by digitising visible crowns in the strips of high resolution (Geo-Eye) imagery in Google Earth. The database is being developed as part of the rapid biodiversity assessment and tropical forest canopies research at King's College London ( . We hope to use it to examine patterns in the distribution of large trees in relation to environmental controls (particularly disturbance) and see to what extent large crowns are an indicator of lack of (climatic and human) disturbance and thus potential for high diversity.

What are we trying to do?

Map the distribution of very large crowns across the Amazon basin.


Large crowns may be an indicator of low disturbance and a surrogate for high levels of biodiversity.

(a) No pan-Amazonian database of large trees exists

(b) Understanding patterns of large tree distribution may help us to prioritize inventory and conservation in an environment which is undergoing rapid change (see other databases at

(c) The distribution of large crowns may also tell us more about current and historic disturbance regimes across the Amazon

How can you help?

Spend a few hours looking closely at any part of the Amazon covered by high resolution imagery in Google Earth and use the built-in Geowiki to digitise the large crowns for that area.

(a) Digitise only those crowns that fall completely outside the 40m circle (i.e. are larger than the circle) .

(b) Do a tile at a time and mark tiles done as you go along.

(c) Do only tiles that are completely covered by high resolution imagery.

Thank you for contributing.