Correcting Route Connectivity

[Important]Important

Refer to the Route Accounts (the section called “Route Accounts”) on how to load your completed route model into Patchworks. Most of the information in this section requires that the route model has been loaded so that diagnostic tools within Patchworks can be used to detect any errors in the road network.

There are two types of route errors that should be checked before running an analysis:

  1. Connectivity of operational blocks to the network. Operational blocks are those that are eligible for harvest treatments.

  2. Connectivity of the road network to the destinations.

Patchworks will check for some simple errors in your road network while it is loading. For example, the model will warn you if blocks are not connected to the network. This warning will not prevent the model from loading, so it is important to track down these warnings and assess whether this is in fact a legitmate error in the pre-processing of the line work or if this was an intentional ommission. Patchworks does not distinguish between operational and reserved blocks when assessing the connectivity of blocks to the road network. These types of warnings should be investigated to ensure that all operational blocks that were intended to be connected to the road network are, so that harvested products can flow to the defined destination.

[Important]Important

Blocks that are not connected to the road network will not be able to participate in road accounts. IF you harvest an unconnected block, the harvest volume will never be able to tally against a mill destination. Conceptually, this would be like cutting a stand and leaving the volume piled up at the landing. Cost may have been incurred for harves and renewal, but the values will not show up at the mill gate. Such a formulation is unrealistic, and would probably yield incorrect results. If a road model is being used, you should make sure that all operational blocks are connectd, or that unconnected block are excluded from treatments.

One way to track down all these unconnected blocks would be to scroll through all the warning messages printed when the model loads, however if there are a large number of blocks this is impractical. Another method that can be used to zero in on unconnected areas is to create a map layer certain route attributes to look for anomalies in the pattern. Here is a recipe to follow to make this check:

[Note]Assessing block connectivity in Map Viewer

  1. Add a layer to the Map Viewer based on the Block Attributes. You can do this by duplicating an existing block layer (right click on the legend item) or by choosing 'Add Existing' from the 'Add Layer' dialog.

  2. Adjust the symbology of the block layer to represent the numeric range of the least cost to destination attribute for each block to the specified destination.

  3. An example of a destination cost attribute would be destination.MILL1.haul. The route cost attributes are located at the far right of the block attribute table.

  4. You would expect a pattern radiating out from the destination from minimum cost to maximum cost (if the cost column you have chosen is based on hauling). You will however be able to see pockets in the planning area that do not follow this pattern. You can then select these blocks to examine the connectivity to the road network and make adjustments if necessary.

[Note]Note

Another way to find the unconnected blocks is to use the Query Tool to select those blocks with a destination haul cost of zero (destination.MILL1.haul = 0). These are the blocks that are not connected to the road network at all and therefore do not have a hauling cost. Any wood harvested from these blocks will not be transported to the mill; making values in the destination route accounts lower than anticipated.

[Note]Note

You can right-click on any block in the dataset to show a detailed menu of data inspectors. One option is to 'Show route to Mill'. If the route layer is also being displayed the route will be highlighted in red to show all segments used in the least cost path to the mill specified. If no route is selected there is no link (linkages.csv) to the network for that block.

The next type of check involves checking the connectivity of the road network to the destinations in the model. This essentially means checking for breaks in the line work in the road access file that prevent an uninterrupted flow of products to destinations.

Breaks can occur when an endpoint of one line does not exactly match the start of another. This commonly occurs with road datasets that have been digitized for cartographic purposes, but have not been built as a "network".

Patchworks provides a number of diagnostic tools to identify unconnected segments in the network. One tool is avaiable within Patchworks when the route layer is the active layer in the Map Viewer. The other 'tool' is a connectivity.csv file that was generated when the route data file were built.

[Note]Network connectivity tools in Map Viewer

  1. Select and display the route layer in the Map Viewer (one destination at a time) and zoom into a single line segment.

  2. Right click to display a detailed menu for the route layer and click 'Select all connected segments'. This will select all the recursively connected segments of this layer and highlight them (both in the Map viewer and the Table Viewer).

  3. Since there are usually more connected than unconnected segments it is helpful to switch the selection to show the unconnected segments. This will help narrow the search. Open the Table Viewer for the route and switch the selection to show unconnected roads.

  4. Use this information to go back and fix the connectivity breaks in the road access spatial file and rebuild the route data files.

Similar information is available outside Patchworks by using the connectivity.csv file created by the Build Road Segments tool in a GIS application. This file contains two fields:

This file can be joined to your road access spatial file to identify the unconnected segments after you have built the route data files. Additional segments or manual snapping could fix some minor problems, or increasing the density of additional roads may also fix the problem.

[Tip]Tip

One other warning you may receive with regards to road networks is that you have loaded a shapefile that does not correspond to the route data files you have specified. This occurs when you provide a link to a shapefile in the global variables section of your PIN file that was not used to generate the route data files with the Build Road Segments tool.