5.2 Importing digital attribute data
In many GIS projects you don’t have to start from scratch. Often a lot of data is readily
available, also in digital format. This is especially true for attribute data such as
the data we are using in this exercise. These data have to be imported into ILWIS and
adapted so that they can be used in combination with maps.
The Import Table Wizard helps you to import different table formats. In this exercise
we will import a dBase file which contains the number of houses in each cityblock
in Cochabamba.
The Edit Columns Details page gives you an overview of columns that are detected
in the dBase file, and allows you to check and modify how these columns should be
imported. You can for instance specify other output column names, the domain (type)
of each output column and whether or not a certain column should be the domain of
the output table. Every default listed on this page can be double-clicked and changed
according to your wishes.
In this case, you can use the existing ID domain Cityblock for the Name column,
instead of creating a new domain for it. This column will also be used as the domain
of the output table.
Now, you will specify column Name as table domain.
Both tables use domain Cityblock. Because of this common domain, you can join
the column Houses from table Houses into the table Cityblock.
Table joining will be addressed extensively in section 5.7.