Walk Area and Obstacles

Walk Area and Obstacles#

After intrinsic and extrinsic calibration, you can define a walkable area and obstacle polygons directly in the calibrated view. This allows you to model walkable regions and export them as a wkt-string in world coordinates (meters). The string may be directly imported in PedPy.

All walk area data is stored in your .pet file.

Important

If you calculate a new intrinsic calibration, you must draw the polygons again.

The resulting polygons are 2D polygons on the ground plane. If desired, polygons can be drawn on a non-zero height (e.g. for tracing the upper edge of a fence). If you draw on an object which is not on the ground plane, remember to set the height correctly for the polygon. The vertices of such polygons are projected onto the ground plane on export.

Requirements#

Before setting up walk area polygons, check that:

  1. intrinsic calibration is active

  2. extrinsic calibration is available and usable

The walk area feature is available in the calibration tab in the walk area section.

PeTrack Workflow#

1. Open the walk area controls#

First, enable:

  • show/hide completely to display polygons in the calibrated view

  • enable editing-mode to start drawing

You can switch between drawing modes using:

  • add walkarea

  • add obstacles

Note

Only one walkable polygon can exist at a time. After creating it, the drawing mode automatically switches to obstacles.

2. Draw polygons in the calibrated view#

Double click the left mouse button in the video view to add polygon vertices. To close a polygon, double click close to the first point.

While editing:

  • Backspace removes the last placed point

  • Escape cancels the polygon currently being drawn

3. Manage polygons in the table#

Each polygon is listed with:

  • id

  • type (walkable or obstacle)

  • height

  • enabled status

You can adjust the height of each polygon and temporarily disable polygons without deleting them. Use the delete button to remove a polygon.

4. Validate geometry#

PeTrack validates enabled polygons automatically. Invalid obstacle rows are highlighted in red.

Typical validation errors are:

  • obstacle outside the walkable area

  • overlapping enabled obstacles

  • walkable area completely inside an obstacle

Export is only possible while validation is successful.

5. Import/Export WKT#

Use the walkarea input/output section for exchanging polygons:

  • export wkt-string exports walkable area and all enabled obstacles as world-coordinate WKT

  • import wkt-string imports WKT and overwrites all current polygons

It is possible to import both POLYGON and POLYGON Z wkt-strings. If a z-value is parsed, it will be set as the height for the respective polygon. Make sure to always use meters as the unit here.

Important

Import replaces the complete current walk area setup (walkable polygon and all obstacles).