Using Point Cloud Data with GIS

In by Harriet Brewitt

We’re pleased to announce the first in a series of guest blogs by Nicholas Duggan a.k.a. Dragons8mycat. Nicholas is heavily involved in all things geospatial, providing mapping and cartographic advice to Garsdale Design as well as being the European Editor of xyHt magazine. We’re delighted to welcome Nicholas as guest blogger and if you’re interested in being a guest on our blog, we’d love to hear from you! 

Make the Most of your Data

I’ve been working with point clouds for well over a decade, whether it is multibeam data, LiDAR data and in the last few years, mostly laser scan data. If someone had told me that I would be using a web browser to view over a gigabyte of point cloud, I would have laughed at them, yet here I sit, with a beautifully rendered and geospatially accurate point cloud of the Silver Jubilee Bridge alongside some 3D buildings.

point cloud data

Silver Jubilee Bridge captured by 3D Laser Mapping with GD3D® streaming 3D GIS data

I will admit upfront that I am not a surveyor BUT for over a decade I have worked alongside many offshore and onshore surveyors to deliver many projects, One surveyor even called me an “interpreter” as I have the skills of a GIS [Geographic Information System] user but talk and work in the survey realm which apparently makes me quite useful, though it mostly gets me involved in lots of discussion about how GIS is a generalisation of the survey data.

Why am I telling you this? Because GIS and survey has changed, long gone are the lines where there was one or the other, now many projects are asking for “hybrid” solutions where the survey data is integrated with the GIS to more accurately analyse and visualise the data, if the two sides can’t talk the same language it can lead to bigger problems.

Just as survey equipment and software has developed over the last few years, so has GIS. It is hard to think that visualising 3D data was something mostly done by the gaming industry 5 years ago but now GIS is capable of a lot more than you would believe.

Modern GIS Capabilities

Coordinate Systems

Using GIS a decade ago was quite frustrating when moving between coordinate systems, in the UK it mostly involved using a Helmert (7 parameter) transformation, giving around 1m accuracy. Now, as I write this, almost all GIS is able to use OSTN15 and if not, OSTN02, furthermore, 3D capable GIS, such as ArcGIS Pro uses vertical datum too. For the last year I have been in conversation with Esri discussing vertical transformations and as I write this, I have pleasure in saying that almost all the vertical coordinate systems you would use as a surveyor are within this software, it is really quite impressive, what really blows my mind is that this is also replicated on the online 3D GIS viewer too.

Point Cloud Visualisation

Using point clouds within a GIS isn’t that modern, in the past we (GIS users) would interpolate the points to create a raster surface that could be analysed. If you were lucky enough to have an RGB image, this could be overlaid to create a mesh, but this could only use the first return.

Recently GIS such as GlobalMapper & Esri’s ArcGIS Pro have been able to read and render point clouds in 3D, this also includes rendering the point cloud using specific classifications such as all returns, first return, RGB, or where types (such as building, land, tree) if they are included.

Other innovations which have been made available is being able to control the point size for the point cloud, even when using the web-based viewer.

Point Cloud Rendering

There is no doubt in anyone’s minds, that point clouds can be big and sometimes difficult to manage but again, GIS has made leaps and bounds to create new ways of rendering the data. Quadtrees and octrees aren’t something you would discuss with regards to GIS but this is where GIS has turned to as a way of displaying these vast 3D data through both the internet and their desktop solutions. Both AGI (Cesiumjs) and Esri have their own formats, AGI being 3D Tiles and Esri the i3s which both render point clouds incredibly fast, the Esri format can be witnessed in the web map above

Using Attribution

Many companies I have met, view their clouds in programs like MeshLab or CloudCompare, which serve a purpose but aren’t very useful when you are trying to get further information, for a little bit more money, you could get the same data provided to you in a GIS and be able to read the attribution each point holds. Yes, that’s right, you can click on a point and read the information for any point you click on, including the x,y and z position.

In Summary

GIS, although not as precise as survey, has started to bridge the gap for visualising and analysing the data which we collect. It serves as a natural way to provide clients a means to view their data alongside other geospatial data which may include high resolution 3D assets, risks, or even floorplans in context. Thanks to data such as that provided by 3D Laser Mapping, Garsdale Design are increasingly integrating clouds with our 3D GIS data.

point cloud data

3D Laser Scanning data for Nottingham alongside GD3D® baseBuilding streaming GIS data

Companies such as Esri and BlueMarble have realised that they need to provide a more aligned service and be closer aligned with the survey world, even to the point where Esri and AutoDesk are providing solutions like the “ArcGIS for AutoCAD” and enabling GIS data from ArcGIS Online in Infraworks

Thanks to Nicholas Duggan in conjunction with Garsdale Design and GD3D.