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At Loggerheads data sets

Authors:Kenneth M. Chomitz  and Timothy S. Thomas
Topics:Environment and Rural Development
Report Number:36789

1. Disclaimer and terms of use 
2. Citations
3. Methods and construction of variables
4. Files and variables 
5. Access to datasets 

1. Disclaimer and terms of use
These data are provided on an "as-is" basis and their accuracy is not guaranteed by the World Bank. All errors are the authors' own. The user acknowledges that no claims, implicit or explicit, are made for the database and that any conclusions or inferences drawn from the data are wholly the responsibility of the user. No conclusions or inferences drawn from the data or accompanying materials should be attributed to the World Bank Group, its Board of Executive Directors, its management, or any of its member countries. The boundaries, denominations, and other information contained in these data do not imply any judgment on the part of The World Bank concerning the legal status of any territory or the endorsement or acceptance of such boundaries.
These data may not be sold or used for commercial purposes.

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 2. Citations:  These data should be cited as:
World Bank. 2007. At Loggerheads? dataset v1.0. Development Research Group, World Bank.

The data contain derived versions of other datasets. Users of variables derived from those datasets should cite the sources as follows. Users are also advised to check for updated versions of those source datasets.

Population data:These data are derived from GRUMP (alpha version), with the following sources:

CIESIN (Center For International Earth Science Information Network), IFPRI (International Food Policy Research Institute), World Bank, and CIAT (Centro Internacional De Agricultura Tropical). 2004a. "Global Rural-Urban Mapping Project (GRUMP), Alpha Version: Land Area Grids." Columbia University, Socioeconomic Data and Applications Center (SEDAC), Palisades, N.Y. []. Accessed December 22, 2005.

———. 2004b. "Global Rural-Urban Mapping Project (GRUMP), Alpha Version: Population Grids." Columbia University, Socioeconomic Data and Applications Center (SEDAC), Palisades, N.Y. [http://sedac.ciesin]. Accessed February 7, 2006.

———. 2004c. "Global Rural-Urban Mapping Project (GRUMP), Alpha Version: Urban Extents." Columbia University, Socioeconomic Data and Applications Center (SEDAC), Palisades, N.Y. []. Accessed December 22, 2005.

Terrestrial Ecoregions data WWF (World Wildlife Fund). 2001. "Terrestrial Ecoregions GIS Database." []. Accessed May 25, 2005.

Described in Olson, D. M, E. Dinerstein, E.D. Wikramanayake, N.D. Burgess, G.V.N. Powell, E.C. Underwood, J.A. D'amico, I. Itoua, H.E. Strand, J.C. Morrison, C.J. Loucks, T.F. Allnutt, T.H. Ricketts, Y. Kura, J.F. Lamoreux, W.W.Wettengel, P. Hedao, & K.R. Kassem. 2001. Terrestrial Ecoregions of the World: A New Map of Life on Earth. BioScience 51:933-938

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3. Methods and construction of variables.
These are described in At Loggerheads?, Appendix B, pp. 240-246, downloadable at Relevant portions are reproduced below.

Land Cover
The Global Land Cover 2000 (GLC2000) database (ECJRC 2003) was used for information about land use and forest cover throughout the tropics. This database is based on 1-kilometer resolution data from the SPOT-4 satellite. Dates for the data range from 1 November 1999 to 31 December 2000. The 23 land cover classifications used by the

GLC2000 are shown in appendix table B.1, along with this report’s 7-class aggregation of these classifications.

Table B.1 GLC2000 Land Cover Categories
Code                  Type of land cover                             Aggregated land cover class 
  1    Tree cover, broadleaved, evergreen                                    Forest
  2    Tree cover, broadleaved, deciduous, closed                        Forest
  3    Tree cover,  broadleaved, deciduous, open                         Forest
  4    Tree cover,  needle-leaved, evergreen                                 Forest
  5    Tree cover , needle-leaved, deciduous                                 Forest
  6    Tree cover,  mixed leaf type                                                 Forest
  7    Tree cover,  regularly flooded, fresh water                            Forest
  8    Tree cover, regularly fl ooded, saline water                          Forest
  9    Mosaic of tree cover and other natural vegetation                Forest
10    Tree cover, burnt                                                                  Forest
11    Shrub cover, closed-open, evergreen                                    Bush
12    Shrub cover, closed-open, deciduous                                    Bush
13    Herbaceous cover, closed-open                                             Bush
14    Sparse herbaceous or sparse shrub cover                               Bush
15    Regularly fl ooded shrub and/or herbaceous cover                Bush
16   Cultivated and managed areas                                              Agriculture
17   Mosaic of cropland, tree cover, and other natural vegetation Mosaic
18   Mosaic of cropland, shrub, and/or grass cover                         Mosaic
19   Bare areas                                                                              Bare
20   Water bodies                                                                          Water/missing
21   Snow and ice                                                                         Water/missing
22   Artificial surfaces and associated areas                                  Artificial
23 No data                                                                                   Water/missing
Source: ECJRC 2003; authors’ aggregations.

Forest Situation Typology
The report defines human-affected rural gridcells as being in "agriculture"or "mosaic" classes (using the 7-class aggregation). It then measures the distance from these collections of cells to areas that are forest or bush in the aggregated classification. The nearest 6 kilometers are called forest edge or savanna edge depending on biome.

Forest or bush cells more than 6 kilometers from the nearest human-affected

cells are designated as forest core or savanna core. But a special rule is applied to small patches of forest and bush cells—those less than 8 square kilometers—that are completely surrounded by agriculture and mosaic cells. These are designated embedded forests. Mosaic forests consist of embedded forests and mosaic cells. Mosaiclands consist of mosaic forests and agricultural cells.

Rural Population Density
The report uses population density figures calculated from the GRUMP (alpha version) population count grid (CIESIN and others 2004b) and the GRUMP area grid (CIESIN and others 2004a). These figures are based on census data reported at a local administrative level—usually the equivalent of a county or municipio, or smaller.

Within the administrative unit, GRUMP identifies the population living in cities, towns, and villages of about 2,500 people or more (CIESIN and others 2004c). The rural remainder is assumed to be evenly distributed across the rest of the administrative unit.

The assumption of even distribution likely overstates the population density of forested and remote areas of the unit and understates the density of agricultural and mosaic areas. So the forest population densities reported here should be taken with caution—as with all  global, spatially explicit population datasets.

WWF (2001) distinguishes 13 biomes. This report’s "forests" comprise three WWF tropical and subtropical biomes: moist broadleaf forest, dry broadleaf forest, and coniferous forest. This report’s "savannas" correspond to WWF tropical and subtropical grasslands, savannas, and shrublands.

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4. Files and variables:

  • Files are in Stata format.
  • ID codes are unique 8-digit identification codes for extraction points representing 1 km square gridcells

- North (lac1n) begins with 1 (originally from Goode's Homolosine region 3)
- South, close to equator (lac1s) begins with 2 (originally from Goode's Homolosine region 6)
- South, far from equator (lac2s) begins with 3 (originally from Goode's Homolosine region 6)

- Northwest (afrnw) begins with 4 (originally from Lambert, 20 east, 5 south)
- Northeast (afrne) begins with 5 (originally from Lambert, 20 east, 5 south)
- South (afrs) begins with 6 (originally from Lambert, 20 east, 5 south)

- West (asiaw) begins with 7 (originally from Goode's Homolosine region 4)
- East (asiae) begins with 8 (originally from Goode's Homolosine region 4)
- South (asias) begins with 8 (originally from Goode's Homolosine region 8) 

Disk 1 part 1 of Loggerheads data

Disk 1 part 2 of Loggerheads data

Disk 1 part 3 of Loggerheads data

Disk 2 of Loggerheads data
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5. Database access: 

Disk 1_Set 1:  130mb                         Disk 2_Set 1: 1,217mb
Disk 1_Set 2:   130mb                        Disk 2_Set 2:  509mb
Disk 1_Set 3:   214mb                        Disk 2_Set 3:  458mb

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