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Support tracing with the draw interaction

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This commit is contained in:
Tim Schaub
2022-08-20 14:11:01 -06:00
parent 31a42949e6
commit f8ba7dec0c
4 changed files with 897 additions and 252 deletions
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examples/tracing.html
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---
layout: example.html
title: Tracing around a polygon
shortdesc: Example of setting up a draw interaction to easily snap to an existing feature.
shortdesc: Using the draw interaction to trace around features.
docs: >
This example showcases how the draw interaction API can be set up to make snapping along
an existing geometry easier while preserving topology, which is sometimes called "tracing".
When the user clicks on two different points on the Idaho state border,
the part of the border comprised between these two points is added to
the currently drawn feature.
This leverages the `appendCoordinates` method of the `ol/interaction/Draw` interaction.
tags: "draw, trace, snap, vector, topology"
The draw interaction has a <code>trace</code> option to enable tracing
around existing features. This example uses the <code>traceSource</code> option
to trace features from one source and add them to another source. The first click
on an edge of the Idaho feature will start tracing. The second click on the edge
will stop tracing.
tags: "draw, trace, vector, snap, topology"
---
<div id="map" class="map"></div>
<form>