Exploring stand attributes in the Table Viewer

Forest stand characteristics (for example, growth and yield) describe the current status and development profile of each individual polygon in the management unit. It is important to understand that the time dynamic nature of the Patchworks model is based on the stand dynamics of individual attributes. Let's illustrate this with a look at the Table Viewer and a few specific stand attributes.


There are several ways to access the stand attribute information in the Table Viewer from the graphical user interface. Here are three methods:

  1. Select the block attribute layer in the Map Viewer by clicking once on the Seral Stages title in the map legend. The layer will appear to have a raised border when it is selected.

    Click the Show Table button on the Map Viewer toolbar to open the Table Viewer for the selected layer.

  2. If the block layer is selected in the legend the block attribute table can be opened using the Show Table option under the Theme menu.

  3. Under the View menu item you can access all currently available data tables in the Patchworks model. Chose 'View Block Attributes table' from the list.

The Table Viewer functions similarly to many database applications. You may scroll through records vertically and horizontally, select records and query for specific information. Each row in the table represents a polygon in the dataset. The columns represent the attributes that describe the characteristics of each block.


Notice the same time scale bar along the far right of the table. Each of the cells represent the value of the attribute at the time period indicated by the slider bar (period 0 represents the initial conditions in the original dataset). Some attributes are static and do not change over time, such as the area of the polygon, however other dynamic attributes (e.g. standing volume) will change through time. For more information about attributes see the section called “The Block Attribute Table” or the section called “The Block Attribute Table”

There are thousands of records in the dataset, each representing a polygon. To find a particular polygon that will illustrate our example we can use the Query Tool. The Query Tool lets you select records using a logical query expression.

  1. Access the Query tool by clicking the Query button on the Table Viewer toolbar. In the Query tool dialog box type exactly what is shown in Figure 6, “The Query tool dialog” (so we are all looking at the same block with a BLOCK value of 3517). If you have used a similar Query tool feel free to use the buttons to construct the query.

Figure 6. The Query tool dialog

The query tool selects a subset of records using a logical query expression.

  1. Choose New Set to run the query and select the block we are looking for.

Although the record has been selected, locating it within the thousands of others is like finding a needle in a haystack. We can find our selected records quickly by promoting them to the top of the list.

  1. Choose the Promote icon from the toolbar and our selected record will appear at the very top of the table.

  2. Move the horizontal scroll bar at the bottom of the table from left to right to see all the information available for this one polygon. Of particular interest is the age of the block found in the column MANAGEDOFFSET (MANAGEDOFFSET refers to the age of the managed portion of the block).


You may have to widen the column headings to see the entire attribute name. This is accomplished by pressing the mouse over the column heading divider and moving to the right while holding the mouse button.

  1. While still looking at the age of our polygon, slide the time slider bar to period 20 (100 years from now). Notice that the age of the polygon is now 172 years (see Figure 7, “Viewing block attributes in the Table Viewer.”. My how time flies! Other attributes describing the stand dynamics of the block will have changed in a similar fashion.

Figure 7. Viewing block attributes in the Table Viewer.

Information for the selected records is displayed in the block attribute table.


Another attribute of interest to us is the VISUAL column. This column indicates the VQO area that the block is located within. The block we have selected belongs to the 1-MI2 VQO.

  1. With the record still highlighted and the time bar at period 20, return to the Map Viewer window if it is not already the top window.

  2. Since the Map and Table viewers share the same underlying data, the record we have selected in the Table Viewer will now be selected in the map. Click the Zoom to Selected Features button on the Map Viewer toolbar to centre the map on the polygon of interest. Your polygon will appear red to indicate that it has been selected as in Figure 8, “Zoom to selected features.”.

  3. To bring the Map Viewer in line with the Table Viewer slide the time slider bar ahead to period 20 in the map as well. Notice how the colour and pattern of the blocks around our block change to represent an older seral stage.

Figure 8. Zoom to selected features.

Zooming to selected features centres the map on the polygon of interest.