The spatial data that was used for the maps was taken from FORIS of the FRA Programme. PONETD was used for boundaries and AW3_INWA for rivers and inland water bodies.
The PONET layer of the Digital Chart of the World (DCW) is the main source for country boundaries in FORIS. PONETD is a processed version of the original PONET from the DCW. PONETD was copied from /X3/FORIS/WORLD to /APP/FOWEB/CNTS. Minor topological editing was performed to remove errors from the coverage. The boundaries were updated to reflect the current political status of countries and territories. The DCW includes first level internal boundaries for the Soviet Union. These areas have been updated to reflect their status as independent nations. From ArcWorld (1:3,000,000), available on-line at ESRI's web site, were extracted the boundaries between Ethiopia/Eritrea, Czech Republic/Slovakia and between the states that emerged from the former Federal Socialist Republic of Yugoslavia. The boundary between China and Hong Kong was dropped, making the latter an integral part of the former.
Attributes were updated to reflect the status of territories as recognized by FAO and the UN in general. This included making Taiwan an integral part of China and making overseas territories of, in particular, France and the United Kingdom separate territorial entities (e.g. Falkland Islands, Barbuda, St. Vincent and the Grenadines), among others. In general, territories were made to conform to the list used for the FAO report State of the World's Forest 1997, and FAOSTAT.
There is no spatial representation of the Holy See (Vatican City) in the DCW; hence no map could be produced for it.
AW3_INWA was copied from /APP/FORIS/MASTERS to /APP/FOWEB/RIVERS. The base scale of the data is 1:3,000,000.
City locations were taken from the ArcView 2.1 CD and have a base scale of 1:5,000,000. For some of the smaller territories that are present as independent entities a capital city was not present in this database. For these territories the main inhabited place was taken from the "Times Atlas of the World, Comprehensive Edition", 1978. For some of the smallest territories no inhabited place could be identified.
Forest cover was available only for the (sub-)tropical countries included in previous publications of FRA. Of all the (sub-)tropical countries the island states in the Pacific Ocean are thus excluded, as well as some small island states in the Atlantic and Indian Oceans. Included in the list of countries are the countries in Temperate South America: Argentina, Chile and Uruguay. There are three separate data sets available with forest cover for different parts of the
(sub-)tropics:
1. Vegetation map of ICIV
2. Vegetation map produced by WCMC
3. Seasonal Land Cover Regions maps of EROS Data Center
It should be noted that none of these data sources are specifically representing forest cover or types. Rather they are vegetation maps, where several classes correspond to forest vegetation.
The data was reproduced from the vegetation map produced by the Institut de la Carte Internationale de la Végétation (ICIV), Toulouse, France, in 1986 (Tropical continental Asia), 1987 (Africa) and 1988 (South America).
The map has been prepared through synthesis of data from different sources, including Landsat MSS satellite imagery, national maps, aerial photography and related documents. Currency, scale and detail differ extensively between different sources.
The map provides a good general impression of the vegetation situation on a regional basis, with a relatively homogeneous classification system. It is of a low resolution, suited for use at a global, regional or sub-regional level. For the smaller countries, the map may not accurately depict forest cover.
This data source was used for the countries in Africa, South and South-East Asia and South America. It corresponds to FORIS sub-regions 11-18, 31-32, 44-45.
The data was produced by the World Conservation and Monitoring Centre, Oxford, UK, at an original scale of 1:5,000,000, and is based on the FAO document "Classification and Mapping Vegetation Types in Tropical Asia", 1989.
The map provides a good general impression of the vegetation situation on a regional basis, with a homogeneous classification system. It is of a low resolution, most suited for use at a regional or sub-regional level. For the smaller countries in particular therefore, the map may not accurately depict forest cover.
This data source was used for the countries in Insular South-East Asia, including Malaysia and Singapore. It corresponds to FORIS sub-region 46, with the inclusion of Papua New Guinea.
The data was produced by the EROS Data Center of the United States Geological Service, Sioux Falls, ND, USA, in the form of the Seasonal Land Cover Regions raster maps. The data was produced through the interpretation of AVHRR satellite imagery taken between April 1992 and March 1993.
The map provides a good general impression of the forest cover on a sub-regional basis, with a homogeneous classification system. The resolution is most suited for use at a regional or sub-regional level. For the smaller countries in particular therefore, the map may not accurately depict forest cover.
This data source was used for Mexico and the countries in Central America and the Caribbean. It corresponds to FORIS sub-regions 22-23.
For all the data sources the original classification was resampled into eight broad classes, in order to provide consistency worldwide. The standard WOVEGT.LUT look-up table in FORIS was used for the reclassification.
Apart from the operations listed above the spatial data was not edited or validated. For the territorial limits, the most volatile of the "non-debatable" features, this implies that the representation in the DCW is assumed to be correct. Since most of the maps are depicted at scales much smaller than the 1:1,000,000 base scale of DCW this is a safe assumption for natural boundaries (sea front) and most artificial boundaries (land borders) between countries. A problem arises however with small countries (e.g. small island states, Andorra, Liechtenstein, San Marino) and countries formed after 1 November 1991, when country status code updates to the DCW was frozen. Countries established after this date are not present in the DCW, although these have been added as elaborated above.
The base material on which the DCW is based, the Operational Navigational Charts (ONC) of the United States Defense Mapping Agency, produced by Australia, Canada, the United Kingdom and the United States of America, was originally prepared in the 1960s and 1970s. Revisions of these base maps have been made mostly in the 1980s, although some revisions are as old as 1973. Artificial boundaries have been updated for the DCW till 1 November 1991. The maximum horizontal positional error is between 500 and 2000 meters (depending on ONC sheet). Islands with a circumference of less than 2940 meters (maximum area of 69 hectares) are not included in the DCW.
Disputed territories as recognized by DCW are only present between China and India and India and Pakistan. On the maps most of these are depicted as separate territorial entities, although they are hardly discernable on the maps of either China or India due to the resolution. Jammu and Kashmir is depicted as an integral part of India. Other disputed territories (e.g. Gaza Strip, West Bank, Western Sahara) are likewise mapped, with no specific reference to claimants or occupier. Disputes that have been settled recently (e.g. between Ecuador and Peru, Chile and Argentina) have not been accounted for in the maps, although these are usually too small anyway to be noticed in the maps.
Small countries, mainly small island states, but including Andorra, Liechtenstein, San Marino, etc., may not be depicted well due to the large scale at which they are mapped. This is particularly true for hydrological and forest cover data. Hydrology is prepared at a base scale of 1:3,000,000. Therefore, it does not combine well with the country boundaries, which are prepared at a base scale of 1:1,000,000 (e.g. border between Liechtenstein and Switzerland on the locator map for Liechtenstein).
The forest cover data is prepared for use at a regional to sub-continental level.
