The CGAZ dataset provides single-file concatantions of boundaries for every country in the world, alongside hierarchical information about what administrative zones each boundary falls in (i.e., what county a state is in). We provide three downloads for this product, for ADM levels 2, 1 and 0, respectively; extensive efforts are made to ensure that file sizes are small enough to be used in most traditional desktop software. Both polygon simplification and gap filling along the edges of polygons are used in this product; this will result in imprecision that may be undesireable for some use cases. If you are working with a single or small number of countries, we recommend you use one of our single-country products. If you need our highest level of precision for your application, we recommend you view our High Precision single country downloads.
Unlike our other products, by its nature CGAZ must define contested areas as belonging to a given country. To do this, we (a) attempt to establish the official ruling of the standardization we're using (currently the U.S. Department of State), and (b) If no official ruling, policy, or other statement exists, attribute the contested area to the country with the largest population. We recognize that this strategy will not be optimal for all use cases, and intend to produce additional world views with different boundary sets in the near future. Further, if you prefer to construct your own world view using our data, you can do so using our unstandardized simplified or unstandardized high precision datasets, which seek to provide boundaries as they are defined by local authorities.
Selecting the best Global Product - Simplification Examples
Our global products each come in two versions, which represent a tradeoff between file size and geographic precision. Today, we focus on two global products: (a) 'low resolution', which are simplified to only 10% of points, and (b) 'high resolution', which use the same files as our SSCGS single country release. Examples of the differences can be seen to the right to help you choose the best product for your use. Of note, the 25% threshold was chosen as a generally effective breakpoint balancing precision with file size; values beyond 25% appear to have rapidly diminishing returns in terms of precision gained.
As usual, the only requirement for use is acknowledgement
|ADM Level||Simplification Level||GeoJSON||TopoJSON||Shapefile|
|ADM0||25% (High Resolution Product)||70MB||12MB||29MB|
|ADM0||10% (Low Resolution Product)||38MB||6MB||16MB|
|ADM1||25% (High Resolution Product)||130MB||20MB||54MB|
|ADM1||10% (Low Resolution Product)||65MB||10MB||27MB|
|ADM2||25% (High Resolution Product)||264MB||73MB||122MB|
|ADM2||10% (Low Resolution Product)||160MB||59MB||80MB|