Preparing Maps

Nesstar is able to simultaneously display multiple layers in a map, but only one will be thematic (coloured based on the values in the statistical data). The other layers will just be sandwiched with the thematic one. Only the thematic layer needs special preparation.

If your data has several levels, for example, Country, Region, District, you will need one prepared map for each level. Geographical functionality such as visually drilling down from one level to another will be automatically handled by Nesstar.

The Shape files must be prepared before being used with Nesstar. This preparation can be done in GIS packages like ArcInfo or by using standard desktop tools that are available on most office computers. Further details on how to use a spreadsheet to accomplish this task can be found at the end of this section.

A Shape file contains a set of properties for each feature, where a feature is a geographical unit in the map. Nesstar is only interested in one property; the one labelled ID. If the maps will not be used outside the Nesstar system, it is safe to remove the other properties to save space and keep things tidy. If no property named ID is present, it must be added.

Map Identifiers

For Nesstar to be able to use the map files for visualizing data, it is important that the Nesstar data and the map files have some sort of common identifier. This is where the ID property comes in. The value in the ID field for a particular feature must match the ID field in the geographical variable in a Nesstar dataset/cube. Usually these ID's are NUTS codes or something similar, but they can be anything as long as they contain only alphanumeric characters.

Preparing the maps then, is the task of adding or editing these ID's so that they match up in Nesstar Publisher and the GeoServer.

Editing a map file

If you do not have a GIS package available to do the map editing, the task described here can also be performed using an unarchiver like WinZip or a spreadsheet package like Excel. Some might find the spreadsheet option easier to use rather than a GIS package.

Shape files are really just zip archives that contain the map coordinates (*.shp), an index (*.shx), and a database file (*.dbf). There can be additional files, but these are ignored by the Nesstar system.

After unzipping the shape file using WinZip or a similar application, the .dbf file can be opened in a spreadsheet program such as Excel. This will reveal a table of data. The first row is the column labels. All that needs to be done is to add the ID column, or edit it so that it matches the id's in Nesstar Publisher.

Please note that the order of the rows in the .dbf file is set (this is how they are linked to the features in the .shp file), so it is important to get the id's in there in the correct order. Usually there is a name column that can be used as a guideline.

When the ID column is in place, save the file as a dbf file, and make a new zip with the new dbf and the old shp and shx files. You should now have a prepared map.

The colors used for thematic maps are the same as are used for charts and other graphs, and are configurable. Please see the Nesstar documentation for how to do this.