Measuring in panoramas from your desk | 360GEO

Measuring in panoramas without going out on site

A panorama you can only look at answers half the questions. How wide is this footway, how high is that cable, how much room is there between the column and the carriageway: those are questions of dimension. In GEORIZON every panorama is a capture station whose position and orientation are known, linked to the point cloud from the same survey round. That turns imagery into measurement, and lets you determine from your desk what would otherwise cost a trip to the location.

Measuring in the browser, without an installation or a licence per user
Distance, width, height and area in the same image
Coordinates in the frame your organisation works in, usable straight away in your GIS
Imagery from any make of mobile mapping system in the same environment

Two ways of arriving at a dimension

Measuring in imagery can be done in two ways, and GEORIZON uses both. The first is photogrammetric: you point at the same feature in two panoramas whose position and orientation are known, and the intersection of the two lines of sight yields a coordinate. That works anywhere an object is visible from two viewpoints and is the classic method used with street level panoramas. The second way uses the point cloud from the same survey round: overlaying imagery and cloud gives every pixel a depth, so a single click suffices. That is faster and also works where only one capture is usable, at a narrow passage for instance, or where an object disappears behind a tree from the second station.

What determines accuracy, and how you keep an eye on it

A dimension taken from imagery is never better than the chain beneath it. The position and orientation of the capture station come from the trajectory, which we compute from the raw GNSS and IMU observations and tie to surveyed control points. On top of that comes pointing accuracy: how sharp is the edge you are clicking, and how far is the object from the capture. Objects close by can be determined more accurately than objects across a square, and a crisp kerb edge is easier to point at than the edge of a shrub. A measurement therefore keeps showing which viewpoint it came from and at what distance, so you can judge how firm a figure is before you adopt it.

From measurement into your own systems

A measurement is rarely an end point. In GEORIZON you store measurements with the project, share them through a direct link to the exact viewpoint, and retrieve them through the open API for use in your own GIS or asset management system. Because the coordinates sit in the frame your organisation works in, they coincide with your existing layers without reprojection. For anyone preferring to work in their own environment, download in common formats remains available. Organisations including ProRail (SpoorInBeeld), the municipality of Nijmegen and Kempkes Landmeten use their imagery as a source of measurement rather than as a picture archive.