Design rule purpose

The purpose of distance-to-nearest design rule is to inform the user about distance to potential constraints or GIS features of interest from every point along the route.

How to configure

Functionality 1: Getting distances to nearest feature at every point of the route

This design rule requires little configuration as it runs automatically if enabled. By default, it the design rule will return distance-to-nearest for all features included in 'constraints' dataset type.

In practice, the design rule identifies all individual features within layers and extracts their edges. In the end, we are interested in the distance to the nearest edge of a feature, not its centerpoint - this is particularly important in case of large features like nature reserves or major sites which can be tens of kilometers long.

Optioneer represents options as centerlines with discrete, interconnected points (sampled around every 30 meters). Since we want the user to know distance-to-nearest feature at every point of the route, the calculation is done on a per point basis. That is to ensure that users can later examine the route and determine potential risks or hotspots.

Distance-to-nearest is recorded on a per-layer basis separately and gives distance to the nearest feature in a given layer. As a result, for every point on the route, Optioneer will return information along the lines of 'at point 200, the distance to nearest feature of layer A is 230m, the distance to nearest feature of layer B is 4500m etc.'

The data resulting from this operation is later available to the user via Optioneer UI, in the Vertical Profile Chart (composition chart, keyword 'Distance') - see below.

Functionality 2: Getting ID of the nearest feature of a layer for every point along the route

As you can see above, two adjacent points often have different features that are 'nearest'. Naturally, it would be good for the user to know when that change occurs. Luckily, Optioneer also identifies the ID of feature that is nearest at a given point.

This functionality has to be explicitly enabled in design rule configuration (under 'Model' tab). There is only one parameter in this design rule - 'Select whether to return IDs of the nearest features'. Set this to True or 1 for this functionality to be enabled.

This functionality operates to similarly to everything described above, but instead of returning the 'distance between a point and nearest feature in a GIS dataset', it returns 'the ID of the feature which is nearest to the point'.

This ID is not currently very informative, but it clearly indicates where the 'nearest feature' changes - see below. Feature changes anytime that the histogram value changes.

NB: All layers are stacked on the same histogram. Other layers might move the layer you are interested in up or down, always check the values on the tooltip (or remove other layers).

Functionality 3: Getting the position index where distance-to-nearest is the lowest.

This is additional functionality which complements the previous two. Optioneer returns a position of the point along the option route where the distance-to-nearest feature within a given GIS layer is the lowest.

Position index means which point along the route the minimum distance is found at. In the example below, the nearest SPA feature is found at the 3rd point of the route, counting from the starting point. This helps locate the minimum, but it doesn't give a chainage (to get approximate chainage, multiply the position by 30m).

Important notes

  1. This design rule runs at the end of Optioneering process and for each option individually. Depending on the size of the project space, it might take up to 30 mins to run. Disable the design rule for 'quick runs'.

  2. IDs returned by 'Functionality 2' might not correspond to the IDs of features in GIS data sets. They should match, but there is no guarantee that they would.

  3. This design rule doesn't provide a plot like the one shown in examples - line of minimum distance is not drawn on the map. The result is delivered to the user via the Vertical Profile Chart and option metrics.

  4. Since the option metrics only indicate the position of the point where the nearest distance is found, there is no point in using them in option comparison. There is no 'comparative significance' that one option has 'Nearest SPA' = 5000 and other 'Nearest SPA' = 3.

Input / output summary

Datasets required

  1. 'constraints' - this design rule will use whatever data is used with constraints. There is no special processing required for this design rule to take advantage of said data.

Input parameters

Name

Example value

Unit

Enable 'get ID functionality'

True

True / False

Output parameters

Name

Example value

Unit

Distance to nearest feature at every point

Example name 'Distance to Woodland' for layer called 'Woodland'

Plot on vertical chart, see this section.

meters, every layer with a separate distance

ID of nearest feature at every point.

Example name 'Nearest SPA' for layer called 'SPA'

Plot on vertical chart, see this section.

ID of GIS feature within the dataset

Position along route of nearest feature

1224

Index of point along the route

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