The following information is from the readme_ftp.txt file available at the CIESIN website.

Created 20 April 2000
Updated 1 May 2000
Updated 11 November 2000
Updated 13 February 2001
Updated 29 March 2001

Gridded Population of the World, Version 2 (GPW)

Contents:

DESCRIPTION
CITATION
NOTES FOR ARCVIEW USERS
DATA RESTRICTIONS
DATA ERRORS, CORRECTIONS AND QUALITY ASSESSMENT
NO WARRANTY OR LIABILITY

DESCRIPTION

This ftp archive contains the final release of CIESIN, the International Food Policy Research Institute and the World Resources Institute's Gridded Population of the World, Version 2 (GPW) data product. Documentation for these data is available on the GPW web site at:

http://sedac.ciesin.columbia.edu/plue/gpw/

This is the final release of the GPW product. If you should discover any problems or errors, please inform us at:

The archive contains grid for the world, continental breakdowns and individual countries as zipped individual ArcInfo interchange files and tarred Band Interleaved by Line (BIL) formats. The BIL format grids have been rounded to the nearest whole number and are stored in integer format while the ArcInfo interchange files store floating point (decimal) values. The grids are contained by region on CIESIN's ftp site (ftp.ciesin.columbia.edu) in subdirectories as follows:

pub/gpw/global		Grids for the World
pub/gpw/africa		Grids for Africa
pub/gpw/asia		Grids for Asia
pub/gpw/europe		Grids for Europe
pub/gpw/n_america 	Grids for North America
pub/gpw/oceania		Grids for Oceania
pub/gpw/s_america 	Grids for South America

See the file n_convention.txt on the ftp site in /pub/gpw/ for details on the naming conventions of the grids.

Ancillary data are available in pub/gpw/ancillary/ and low resolution versions of the grids are available in /pub/gpw/lowres/

CITATION

We recommend the following for citing the database:

Center for International Earth Science Information Network (CIESIN), Columbia Policy Research Institute (IFPRI); and World (GPW), Versionitute (WRI). 2000. Gridded Population of the World 2. Palisades, NY: CIESIN, Columbia University. Available at http://sedac.ciesin.columbia.edu/plue/gpw.

NOTES FOR ARCVIEW USERS

The ArcInfo interchange files on the ftp server can be converted to grids using ESRI's Import71 utility. However, this utility is much slower at creating the global and continental grids than the ArcInfo import command. Downloading the BIL format data and converting them to grids using ArcView's 'Convert to Grid' option is a quicker way to access the grids.

There seems to be a bug in arcview which prevents the correct display of some grids in a view or a layout according to the legend. The bug affects grids with a range greater than 1-1,000,000 for floating point grids and 1-100,000 for integer grids. The grid values are correct but the colors are not the ones in the legend. The workaround around is to reclass the grid into the classes that you want to draw (as long as you don't want > 100,000 colors on your map!).

DATA RESTRICTIONS

These data are for noncommercial use only. No third party distribution of all, or parts, of the electronic files is authorized. Additionally, due to restrictions on the input data for China, the data from the China portion of GPW v2 are restricted to scientific research use only. The data used in the creation of this product were provided to CIESIN by the organizations identified in the source data table (available via http://sedac.ciesin.columbia.edu/plue/gpw/).

No third party distribution of all, or parts, of the electronic files is authorized. The data used in the creation of GPW were provided to CIESIN by the organizations identified in the source data.

DATA ERRORS, CORRECTIONS AND QUALITY ASSESSMENT

CIESIN follows procedures designed to ensure that data disseminated by CIESIN are of reasonable quality. If, despite these procedures, users encounter apparent errors or misstatements in the data, they should contact CIESIN Customer Services at 914/365-8920 or via Internet e-mail at ciesin.info@ciesin.org. Neither CIESIN nor NASA verifies or guarantees the accuracy, reliability, or completeness of any data provided.

NO WARRANTY OR LIABILITY

CIESIN provides this data without any warranty of any kind whatsoever, either express or implied. CIESIN shall not be liable for incidental, consequential, or special damages arising out of the use of any data provided by CIESIN.