General data

Procedure of creation of thematic cartograms is intended for forming graphic representations, visually illustrating a ratio of values of the chosen characteristic for separate objects of an electronic map.

To processing in the given procedure the objects, preliminary selected on an initial electronic map (for example, by means of search and marking), are exposed.

The information according to which the selected objects of a map will be painted can be contained in semantics of objects or in the table of the user database of .dbf type.

For creation of thematic maps both tables preliminary connected to a map and tables not having links with a map can be applied.

Linked tables are characterized by presence in their structure of fields LINKSHEET and LINKOBJECT, containing references to concrete objects of a concrete map. In LINKSHHET field the sheet nomenclature (the conditional name) is stored on which the object corresponding to the given record is located, and  in LINKOBJECT field - its unique number.

However, if you use the table in which direct links with objects of a map are not established, it is necessary to provide an opportunity of an establishment of such link. It means, that in semantics of the selected objects there should be values (binding semantics), which unambiguously can be compared with values of a corresponding field of concrete record of the processed table (a binding field).

For example, you have map of administrative division of Russian Federation where regions are submitted as the polygons, having in semantics a code (number) of corresponding region, and the summary table of the information on regions, one of which fields - a code of region.

Link can be established both by numerical, and by character values (for example, the Name of region), unique restriction is that the binding semantics and the binding field should have identical type (both numerical or both character).

With the help of the given procedure it is possible to construct diagrams of three types:

- Diagram of percentage;

- Diagram of elements presence;

- Diagram of prevalence.

You can find detailed characteristics of diagrams types in the description of Value bookmark.

Dialog window of procedure contains the menu (File, Names, Processing and Help) and 7 bookmarks (Data, Link, Values, Size, View, Type and Legend).

The sequence of bookmarks corresponds to sequence of actions at creation of a thematic cartogram, i.e. for successful execution of procedure it is necessary consistently to enter all bookmarks, since Data and finishing Legend and to make corresponding settings.