“The world we live in is a three dimensional world, so why do we map it and analyse it in just two dimensions?” – Dragons8mycat 2013

 

In the last 5 years we, the GIS industry, have made some fantastic advances. So why is it that we are so slow with the adoption of using 3D data? Surveyors take data based on a 3D location, where does this third dimension go?

 

Admittedly 5 years ago 3D visualisations were more a tool for allowing senior management to visually understand the three dimensional problems at hand or to get people to buy into your capability. They were cool times and even though the software was quite specialist, a 3D visualisation was part of every large project deliverable….though any GIS expert who has been part of those projects will at this point raise their hands and say that none of the GIS data was used at any time for the visualisation. Furthermore, until the last few years, sharing 3D data has been difficult, with many people stitching together snapshots or putting a movie onto DVD/USB for the client.

 

This isn’t the case anymore, so why are we still flat-minded?

 

It is safe to say that thanks to the evolution of ESRIs’ CityEngine and QGIS’ QGIS2Threejs, 3D has become a GIS tool, and here is the basic and most core reason why – 3D visualisation of the past used to require that you stripped data of its coordinates so that you furthest  most extent would be your basepoint, a little like AutoCAD. Even with the most complex 3D modelling tools which allowed you to use georeferenced 3D data, you would find that once processed, these models had no reference in the real world and were no more than objects.

 

Here is a simple 3D model built using the QGIS tool ‘QGIS2Threejs’

 

[iframe src=”http://www.dragons8mycat.net/OS3D/OS3D.html” width=”800px” height=”600px” scrolling=”yes” ]

 

 

As you can see, the tool allows the user to not only manipulate the object in 3D but you can also take coordinates from the objects, this provides context to the model and changes it from a mere visualisation to an informative model.

 

Another great example is the ESRI campus 3D model:

Clicking around the campus retrieves attribution for objects and also hyperlinks to further information.

 

These 3D models are no longer just simple visualisations, these are informative models which are scale representations of real world objects.

 

Admittedly, the collection of the data limits the “realism”  a little, therefor data collected to 2m accuracy would not show detail such as roof direction or an exact building outline, but does this really matter if it is to understand how things interact with each other or to understand visibility at a high level?

When we analyse line of sight or visibility analysis, we use a 5m DTM [SNH guidance] as an industry standard and no-one bats an eyelid.

 

So, here’s the thing, we need to get over the level of detail [LOD] issue when talking about 3D models, it isn’t always about how accurately the model mimics the real world. For many users 3D enables the ability to see the issues in context and see where conflicts may occur.

 

3D isn’t a fad, there are many geospatial analysis which can ONLY be done in 3D

 

 

There have been many times where I have been glad I invested my time into learning 3D tools and for me, the prospect of GIS becoming more 3D is one which I embrace. Take for example volumetric calculation – A client has a lot of mud which needs clearing, how do you get an accurate volume which needs extraction?

Fall out areas, on a 2D map they are a simple buffer of the centre, though these issues rarely lie with just the flat plane, so to be able to calculate the extent as a dome buffer or set of dome buffers, changes the calculations entirely.

 

The issue lies that most 3D tools have to be used with 2D GIS and then visualised in a 3D environment, there isn’t (currently) a software whereby you can perform the analysis in 3D in realtime…..though it is close, with ArcGIS Pro and also QGIS talking and demonstrating solutions which aren’t far off.

 

With more use of 3D and promotion, it will mean the we realise the true 3D GIS sooner rather than later. I for one, look forward to the day I can use a 3D model whereby I can click on objects and extract information or analyse something to ensure the right decisions have been made.

 

We need to actively promote extending the integration of 3D tools into 3D GIS as the clever bloke at the start said:

“The world we live in is a three dimensional world, so why do we map it and analyse it in just two dimensions?”