Maps are displayed on both the taxon overview pages and on the special 'map tab' of taxon pages. There are three different data sources for these maps: GBIF, specimen data, and taxon description data. Not all maps have all three data sources, but all three can be combined and displayed on the same map. It is important to recognize the limitations of all three data sources and how each introduces different biases into the display of distribution data. We are a far way off from comprehensive species-level distribution data for ants, and this is reflected in the site's maps.
Data Sources
GBIF. These data are dynamically sourced from the Global Biodiversity Information Facility and appear as very small yellow to red dots depending on the density of records for each locality. There is a selection box at the bottom of the map that allows users to turn the GBIF data on/off. GBIF data for ants are best viewed with a skeptical eye, as they are primarily taken from the literature (rather than from specimens) and are not subject to rigorous quality control.
Specimen data. Each specimen on the site associated with a 'Location' node is displayed on its taxon page's maps as either as either an individual place mark or as a group place mark in cases where specimen density is high for a given region at a given scale. At this point all the specimen data is imported from Antweb. These specimen data have the advantage of high quality control, but the disadvantage of being idiosyncratic with respect to sampling. The Madagascar, Costa Rica and Fiji projects, for example, have large numbers of georeferenced specimen data, while other regions and countries have very little or no georeferenced specimen data. This can give the false impression that the species is absent from many regions where it actually occurs.
TDWG regions. The TDWG Biodiversity Information Standards include geographically delineated TDWG regions. The Scratchpads interface allows site editors to select these regions on a map when editing taxon descriptions. These regions will then be displayed as shaded on the taxon page map. These regions can also be bulk imported. The shaded TDWG regions allow users to get a good general idea of the taxon's distribution, but only at a very course level. For example, if a single specimen of the given species is known from Brazil, the entire country of Brazil might be shaded giving the false impression that the species occurs across the country and all its various habitats.
Comments
TDWG Regions
None of the taxon pages currently display TDWG Regions. I expect this could be a fruitful avenue for future content development, especially if the data were imported. I used the map tool in the taxon description editor to select TDWG Regions for ~15 species. Unfortunately those changes were lost during subsequent development, but I had mixed feelings about the results. For example, how do you map a 'Neotropical distribution'? Does that include all of South America up through all of Mexico, or is it more accurate to exclude southern South America and northern Mexico? The TDWG regions do not allow for selection of administrative units below the province/state level, and species tend not to feel confined by political boundaries. However, when combined with specimen data, these coarse-scale maps have the advantage of at least being able to demonstrate the basic global distribution of a species even when specimen data is not available for particular portions of it. Also including the specimen data should help give the impression that the populations are much more localized than the shaded TDWG regions imply.
Why is the default view of Europe?
If there is no specimen/location data and no TDWG regions were selected for the taxon description, the default map view is of Europe. There might still be GBIF data, but the map does not automatically use that data to display its default extent. I suspect that the Scratchpad team made Europe the default extent because that project is based there. I've requested that the default extent be changed to a more global so as not to give the false impression that all species lacking distribution data occur in Europe.