Summary 

For decades, world-wide flora has been mapped in various extents. The growing need for chorological data in scientific and experts' disciplines, and specially in preserving biological diversity, increased importance of defining the distribution of flora. Numerous regional, national and other atlases have been published in past decades, often as a result of internationally co-ordinated activities.

Literature and herbarium collections, as well as undoubtedly the most precise new data generated during the field work, are being used as a source of chorological data. Fundamental condition for such work is an existence of well-defined taxonomic and geographical units. While the basic taxonomic units are actually the contents of check-lists and Floras, geographical units are more a matter of methodological issues (application of the artificial areas, basic grid units of indirect mapping, real co-ordinates of localities, areal areas). Selection of a method depends on many factors: accuracy of data source, available staff, mapping area, coexistence with present standards, technological resources, basic maps, etc. Vast amount of data collected by mapping of national floras, need to be manipulate by, today well developed, computer tools (RDBMS, GIS).

Necessity for mapping Croatian flora exists. However, its realisation includes many objective difficulties: lack of educated staff, accuracy of existed data and standardisation of certain procedures. Existed chorological data are not coexistent regarding to: taxonomy (lack of recent revision), precision (13 to 50% of data are insufficient by precise), accuracy (77 to 86% of data are older then 50 years), cartographic base, applied geocoding method (real co-ordinate, MTB, UTM grid). Therefore, standardisation of procedures and methods is necessary for purpose of manipulation with existed data and collecting new ones.

Here proposed standards for mapping of Croatian flora tried to take into account reality of caring out such a project under present conditions, as well as compatibility with similar European projects.

The proposal defined basic taxonomic units, method of indirect mapping, basic geographical units (MTB grid squares, standard labels and names for MTB units, MTB 1/4 1/16 and 1/64 grid squares for smaller areas), cartographic bases, display of distribution on the 1:4.000.000 maps (Transverse Mercator projection, 5th zone, central meridian at 15°), MTB basic square grid and conceptual examples for constructing databases.

Standard labels and names, as well as grids of basic UTM squares, geographical regions with names and fixed boundaries are given, to make easier exchange and accumulation of data.

In enclosure there are "blind" maps of Croatia as assistance for technical applicability of proposal, which are also available in the other formats and media including the corresponding Internet service.