As part of the National Aggregates of Geospatial Data Collection, the PLACE data set permits easy comparisons across countries on such measures as the number of persons living within 100 kilometers of a coast, the percent of territory above 2,000 meters, or the number of persons living within different climatic zones. The data set includes estimates of national-level aggregations in the following thematic areas:

• biome
• climate
• coastal proximity
• elevation
• population density

METHOD

This map demonstrates a simplified version of the methodology used to construct the PLACE data set. The purple shades, from light to dark, indicate population density, from sparse to high. The red dots, from few to many, indicate the 5 elevation classifications. Black indicates national boundaries. The intersection of these data sets (at higher resolution than shown here) is used to generate estimates in the PLACE data set.

The area figures were calculated by first overlaying the variable in question with national boundaries and then estimating the area within each national boundary that overlaps with the values for that variable. For continuous variables, we assigned discrete classes; for categorical variables, we used the classifications provided in the source data. Such area processing yields a measure, for example, of the percent of a country's territory that is within 100 kilometers of a coast. Similarly, the population figures were calculated by first overlaying the variable in question with both national boundaries and gridded population and then estimating the number of people within each national boundary that overlaps with the values for that variable. This three-dimensional processing yields a measure, for example, of the percent of a country's population living within 100 kilometers of a coast.

With respect to area estimation, all the data sets were projected to Mollweide equal area projection. For population estimates, data were converted to geographic (latitude/longitude) coordinate system to match with the reference coordinate system of GPW.

Coastal boundary data available in geographic (latitude/longitude) coordinate system were projected to cylindrical equidistant projection system. The projected data were buffered within 100 and 200 km from the coast. These two buffer layers were then reprojected to a geographic coordinate system to match with the GPW data.

AVAILABILITY
Data are available (via ftp) in Excel format. Associated codebooks and documentation may also be downloaded in Rich Text Format (RTF).

EXAMPLES
An example of PLACE data, for a select group of South American countries, can be seen in both the elevation table and graph below. The table shows the proportion of area and the proportion of population living within 5 elevation classes.