POSITIONAL ACCURACY:

Latitudes and longitudes are those interpolated from the publications that reported the fossil sites. In most cases these are not exact. Rarely were latitudes and longitudes reported, especially in older literature. Commonly, geographic positions were given in USGS section, township and range. These coordinates were converted to latitude and longitude by using the conversion routines at http://www.esg.montana.edu/gl/trs-data.html or http://www.topozone.com (now http://www.trails.com). In some cases only a geographic description was given in publications; these localities were assigned a latitude and longitude that corresponded with the geographic description, thus are only approximations of where the true locality lies, and in the worst cases are plotted at the center of the county in which they occur. Color coding showing the accuracy of sites is available on the interactive maps.

Accuracy is expressed as:

EXACT if the latitude and longitude were reported;

TOWNSHIP if the latitude and longitude was inferred from a USGS section/township/range description;

QUAD PRECISE if the locality description allowed precise placement on a USGS quadrangle map (usually 7.5’);

QUAD APPROX if the description allowed placement on a portion of the map but was not detailed enough for precise placement;

COUNTY CENTER if the locality information was so lacking that the best resolution was placing it in a certain county.

In general, EXACT and TOWNSHIP imply that the locality is within a 1km radius of the latitude and longitude in the database, QUAD PRECISE within about a 5 km radius, QUAD APPROX within about a 10 km radius, and COUNTY CENTER within a county.

A representative number of localities were verified on the map plots to ensure that major positional errors were not present. In general the positions are those inferred from our reading of the primary literature and have not been ground-truthed. Latitudes and longitudes were recorded using the WGS84/NAD83 coordinate datum.

As of 2004 the Landsat images used in the map interface and provided by the JPL WMS service have an offset of 100-200 meters worldwide. JPL was working to fix this but it is unknown when the fix will be completed.

 

*Use of this resource in publications should be cited as:
Carrasco, M.A., B.P. Kraatz, E.B. Davis, and A.D. Barnosky. 2005. Miocene Mammal Mapping Project (MIOMAP). University of California Museum of Paleontology http://www.ucmp.berkeley.edu/miomap/