Selecting the data

1. Adding new data entries

From the top menu of the MODEL tool click on the Select Data button. A list containing the data entries for the project will be displayed. If we have started a new project then this list will be empty.

To add a new data entry, from the menu below the data list click on the Add button. A data selection panel will be opened.

In this panel we may define the name of the new data entry (10 characters maximum), its description, select the .shp (Shapefile) file containing the actual data and the field which will give the data values for each feature inside the file. After selecting the .shp file the list of fields below will become populated and upon selecting a field, a list containing the existing values for that field is displayed below.

Pressing the OK button will save the input information and return you to the Select Data panel, where a new entry in the data list has been added.

2. Editing and deleting data entries

Data entries may be edited by first selecting an entry from the data list and then pressing the Edit button from the menu below this list.

The same data selection panel as above will be opened containing the information for the selected data entry. This data may be changed and the changes will be saved upon pressing the OK button.

Deleting a data entry can be done by selecting an entry from the data list and then pressing the Remove button from the menu below this list.

3. Displaying data layers

All the data entries may be displayed in the QuantumGIS interface using the Show Data Layers button from the menu below the data list inside the MODEL tool. The layers from the data sources for the data entries (.shp files) will be displayed.

4. Calculating the bounds

At the very bottom of the Select Data panel we find a set of elements used to get the map bounds. These bounds are calculated from all the features of the layers of the data entries. Press the Get Bounds button to do this.

All the elements of the MODEL interface will become disabled, except for a progress bar at the bottom and the Cancel button. The progress bar shows the progress of the operation of calculating the bounds for the project. The Cancel button may be used to stop this operation. Upon canceling or finishing the operation, all the elements of the MODEL interface return to their previous state.

An additional buffer may be used in order to construct a slightly larger map. The parameters for this buffer may be changed at any time without the need to recalculate the bounds. The Show Bounds button may be used to display a layer containing the bounds in the form of a rectangle.