Mars Feature Coordinates Updated to MDIM 2.1

11 August 2011

The Mars portion of the Gazetteer of Planetary Nomenclature now defaults to a new set of coordinates; all of the Martian features now match the Mars Digital Image Mosaic (MDIM) 2.1 control network.

In late 2010, the coordinates of the named craters in the Martian portion of the nomenclature database were updated from values from the MDIM 2.0 control network to values in the MDIM 2.1 control network. In the spring of 2011, the remaining Martian features (i.e., all the named features that are not craters) were also updated to MDIM 2.1. Since the MDIM 2.1 network was tied to local Digital Elevation Models (DEMs) generated from Mars Orbiter Laser Altimeter (MOLA) data, this implies the features now match MOLA data products and other products in that reference frame. The GIS download that contains all of the features in the MDIM 2.0 control network is still retained in the gazetteer, but is now considered archival and will not be updated with new names or changes to approved names.

The extents and sizes of the named features were also updated, and vectors describing feature boundaries were drawn; these data are approximate and are intended solely to give the user sufficient information to identify named features and their rough extents.

This work was accomplished using ArcMap version 9.3.1 and theMars Digital Image Mosaic 2.1. Some features are not resolved well in the 2.1 mosaic; for these cases, feature coordinates were derived from the Thermal Emission Imaging System (THEMIS) Day IR 100m global mosaic. We would like to thank Stuart Robbins (University of Colorado, Boulder) for sharing a portion of his global crater database, which provided a valuable and time-saving starting point for the crater portion of this work.