----------------------------Original message---------------------------- As far as our practise goes the past 20 years the precision in giving coordinates depends on the scale of the map. Topographic maps (1:10,000 - 1:25,000 - 1:50,000) give coordinates up till geographic seconds (sexagesimal) so we catalogue them. The same for townplans of Amsterdam and The Hague 1:1,000. If not mentioned on the map we use geographic minutes for scales 1:10,000 - 1:500,000 and degrees for over 1:500,000. We always use Greenwich as prime meridian as the coordinates are meant for retrieval purposes. Centesimal degrees therefor are converted to Greenwich sexagesimal. In structured fields and notes is remarked that the map shows Greenwich or other prime meridians. Not only French maps carry their own prime meridian (Paris), but e.g. also Spanish maps (Madrid) and probably several others. The Paris prime meridian was in the third quarter of the 19th century e.g. also used on maps in Petermann's Geographische Mitteilungen, a famous German geographic journal. For further information look into: "Cartographic materials : a manual of interpretation for AACR2" (1982), probably to be gotten from the American Library Association. Jan Smits Map Curator Koninklijke Bibliotheek, National Library of The Netherlands E-mail: [log in to unmask]