Purpose

This technote will go over how and when to use the template tool, and specifically focus on workflows for curbs. However, these practices can be applied across a large variety of features.

When to use

Use the template tools for extracting breaklines from features whose profile shapes remain consistent.

Below are some examples of features that the template tool can be used to extract.

How it works

Scoring System

In order to understand how to best create a template, it's important to know the basics of how tool fits a template.

• The template tools use a best fit algorithm to move a template within a cross-section in order to get the maximum possible score
• The score is the sum of sub-scores, made up by one or more shape and line elements.

Positive Sub-Scores

• Templates are created from shapes and/or lines.
• Every point within a shape or touching a line is summed to get a sub score. A template can be created from several separate shapes and lines.
• The template will be placed within the cross-section wherever it has the highest total score.

Negative Sub-Scores (Voids)

Voids act exactly the same as the rest of the template, except their sub score subtracts from the total score.

• Voids are excellent for managing noisy areas where the original profile is not easily seen, eg. curbs with high vegetation overgrowth
• A general rule of thumb for voids is to only place them on the inner parts of a profile or wherever no points should exist. Eg. inside of a curb, underneath the ground.
  Do NOT place a void where there is noise and vegetation you are trying to avoid!

• These images illustrate how the algorithm would calculate where to place the template.
• Fig. A1 has the highest score overall, but is too high
• Fig. A2, a void is added. The templates in Fig. A1 & A2 are in the same place
• Fig. A3, the template is in the highest scoring position and the correct placement.

• Voids are created simply by setting their Line-Style to 5
• Color does not affect templates in any way

Multipliers

• Lineweights act as multipliers to each template
• A shape with a lineweight of 2 will multiply the sub-score twice as much as templates with a lineweight of 1

• Fig. B1 the template is pulled toward the denser data on the ground than the curb. Both templates have the same weight
• Fig. B2 the template is in the correct place due to the green shape having a higher weight. Without it the total score would be 56, lower than the total score of 57 in Fig. B1

Creating Templates

Walkthrough

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1. Trace a line through the profile of the feature being extracted.
2. If the feature changes height often (eg. curbs) do not trace the entire profile, only trace one distinct part, such as a corner.
3. Use the parallel feature to copy the line and encompass the points in the profile.
4. Close the paralleled lines and use the Create Complex Shape tool to create a shape.
5. Increase the weight of the original traced line so that it is more than that of the encompassing shape.
   NOTE: Elements within other elements must have a higher weight than those encompassing it for the total sum to be higher
6. Test the template using the Test Elements for Template tool (more in detail in a later section).
7. Adjust template as needed.
8. Add template breaks using the Define Template Break tool (more in detail in a later section).
9. Add origin using Define Cell Origin tool. This origin is where the template will be located relative to the defined directional line.
10. Create a cell and add to cell library. Your template is ready to use.

Template Tester

• Use the Test Elements for Template tool to test your template before creating a cell
• Test it in several areas and conditions along the feature you are extracting. Adjust as needed
• Once satisfied, add Template Break Points in the appropriate places
• NOTE: If there are Draped Break Points, they will be moved with the template, but not draped as they would be when run in the template extraction tools

Defining Breakline Points

• Use the Define Template Breaks to place where the break points will be placed at each interval
• You can choose the level for each template break. These breaks move rigidly with the template.
• The exception to this is when using the Drape to Point Cloud option
• This will drape to the ground using the same algorithms the Drape to Data tool does. The only difference is that you can choose an upper and lower limit, which allows it not to drape too far downwards (eg. point in a drain).
• NOTE: It is important to ensure the Data Noise Thickness under Point Cloud Settings are accurate for it to drape properly

• Templates are cells made up of lines, shapes, and template breaks
• Templates can be created in many ways. Typically, this is the preferred way:

Using the Template Tools

• When using the extraction tools, be sure the templates are oriented correctly. You can tell this by checking the green and red bars on either side of the template image and sample box.
• The orientation can be flipped by clicking on the template image.

Extract Template By Direction

• Extract Template By Direction allows you to simply choose a starting point and a direction and allow the tool to choose the path.
• This tool is ideal for features with unbroken profiles for long lengths (eg. no driveways to breakup a curb) and paths that do not change sharply.
• The stronger the path of the feature curves, the smaller the intervals must be
• This tool will terminate when it hits a low score, the threshold being relative to itself, after exhausting the set Error Intervals. Eg. if working on a static dataset, the tool may terminate in between scans where the data is less dense.

Extract By Path

• This tool works similar to the directional template tool, but the user defines a path.
• This tool is ideal for features with varying densities, sharply changing paths, or short sections. Eg. Curbs between driveways, intersection corners, low densities between static scans, etc.
• You can create a path using a linear line, a spline, or an existing line element (ideal for testing multiple templates).
• The option Stop at Linear Path Vertices can be enabled to also set breakpoints where the user clicks along a path, useful for placing breaks where there are distinct breaks in the feature being extracted

Extract By X-Section

• Extract by X-Section extracts points only at the defined cross section
• This is ideal for testing (the drape break points will be draped), connecting separate breaklines, specialized tools (eg. Fit Arc Tools), etc.

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