Monthly Archives: April 2015

Linknode are recruiting

We currently have an opening for a Sales and Account Management position.


An active role in sales and account management for Linknode’s VentusAR product. Leading customer acquisition and closing deals to meet targets for this exciting brand is a fantastic career opportunity. Reporting regularly to the directors, and working closely with marketing, the role is fully supported at the highest level and an integral part of the business development team. Identification, qualification, technical communication, value assessment, business proposal writing and conversion make up our process. Our customers are all professionals on B2B relationships. A pipeline of potentials is available for immediate exploitation via the CRM and office infrastructure.


We are looking for great people, like you. Personalities trump qualifications in this role – you will be able to create relationships with our accounts and understand the business needs to apply the right solution. Rigorous approaches and discipline in sales identification, qualification and value-driven experience are an advantage here. Ideally, you will have experience working in a close-knit group or SME, and have an understanding of the constraints and opportunities that creates. An understanding of the renewables energy industry (scoping and planning) is an asset, but not essential.


VentusAR was launched in 2013 to provide innovative visualisation services to the onshore wind industry. It provides accessible and relevant mobile visualisation of data from any location – making planning more personal and engaging. Professional developers, landscape architects, planners and communities use it to understand developments better and make more informed decisions; faster. Linknode are a Glasgow-based SME specialising in the development of new solutions that integrate 3D and geospatial data with mobile technologies to provide innovative systems. Our core “GIality” technology is the platform for VentusAR and is under development for use in a variety of other sectors.


Negotiable. Sell yourself.


Send an introductory email directly to (in person, no agencies please).


It’s On / Under the Horizon

We all know the earth is not flat (well, apart from members of the Flat Earth Society).

Popular belief says that in the middle ages, sailors didn’t want to sail too far from their home port in case they fell off the edge of the world (though a quick bit of research on Wikipedia would suggest that this is a bit of a myth).

The earth is a complex shape, mathematically defined as a geoid (TL;TD – Wikipedia) or, more simply, it can be represented as an Oblate Spheroid (“oblate” because it is slightly oblong in appearance, “spheroid” because it is almost a sphere, but not quite) or rotated ellipsoid. VentusAR allows you to see far enough that we need to correct for curvature and ensure that the terrain shown in our 3D visualisations is not considered to be flat either.

There are a couple of good reasons for doing this: It makes our visualisations accurate when using a large viewing distance and it is required to be compliant with SNH standards for visualising windfarms. You’ll hear us talking alot about SNH standards for visualising windfarms over the next few weeks and months. We are in the process of making VentusAR capable of producing photomontages, wirelines and panoramas that are compliant with SNH Standards. So this is the first of several changes we’ve made to VentusAR to make the process of producing photomontages quicker (and therefore cheaper). Stay tuned to future blogs to hear what else we are doing.

Not correcting for earth curvature can make a huge difference to what can and cannot be seen. Over a viewing distance of 30km, a 60m turbine could drop completely out of sight. Consider the scene below: not correcting for earth curvature would suggest the tips of the turbine would be visible over the terrain. However because of earth curvature, the turbine tips would actually be hidden below the terrain.

No earth curvature correction: the turbine tip is visible over the terrain.

No earth curvature correction: the turbine tip is visible over the terrain.

Actual Model: The turbine tip is hidden behind the terrain

Actual Model: The turbine tip is hidden behind the terrain

SNH have produced guidance on how to include Earth Curvature and Atmospheric Refraction in your visualisations. Their requirements are published in their updated Visualising Windfarms guidance (v 2.1) – See Annex D on page 50. There are two corrections we need to make to calculate how much of a windfarm would be hidden behind the terrain: Earth Curvature and Atmospheric refraction.


Curvature is the most significant component that has an effect on how much of a windfarm is hidden behind the terrain. It is then a case of using Pythagoras theorem to calculate the height drop on the object. The equation used to calculate the vertical correction (the number of metres we should drop an object) due to earth curvature is shown below. [Note: there is an approximation in this formula, however unless you can see a distance approaching the radius of the earth – 6367km – it has a negligible effect on the maths].



  • h is the vertical correction in meters
  • c is the distance from viewer to object in meters
  • r is the radius of the earth in meters (6,367,000)


In reality, rays of light in sightlines are also curved downwards due to refraction of light through the earth atmosphere. This has the effect of allowing you to see approximately 15% beyond the expected horizon calculated using curvature alone. The standard formula used in surveying work takes into account refraction by adding a refraction coefficient (k) to the equation. For absolute accuracy, this coefficient should be measured at both ends of the line of sight – however this is not required for visualisation and visibility analysis so a reasonable average value of 0.075 has been used.

This makes our equation for working out vertical correction:



  • h is the vertical correction in meters
  • c is the distance from viewer to object in meters
  • r is the radius of the earth in meters (6,367,000).
  • k is the refraction co-efficient (0.075)


To give an idea of the effect of earth curvature and refraction on the visualisation produced, I’ve included a copy of the calculations as printed in the SNH guidance. To put this in context – if you were on a beach looking towards a wind turbine, over a distance of 30km a 60m wind turbine would not be visible because it is below the horizon.

Distance (c) Vertical Correction (h)
5km 1.7m
10km 6.7m
15km 15.0m
20km 26.7m
25km 41.7m
30km 60.1m

Implementation in MonoGame

It is well known that here at VentusAR, we use MonoGame to produce our visualisation screens. We have done two things to allow us to add Earth Curvature & Atmospheric Refraction to the VentusAR My View and Gallery: changed to using shaders and implemented shaders to include the vertical drop required.

What are Shaders

(This might get a bit technical – sorry)

3D Computer Graphics are based on a rendering pipeline. To convert a 3D representation of the world in computer memory, a series of steps are applied to the 3D data to produce something that can be displayed on the tablet screen. This rendering pipeline needs to be completed really quickly to ensure that the animation on the screen looks smooth – 60 times a second. Advances in computer graphic have given rise to powerful graphics cards to handle this processing. MonoGame allows developers to customize the processing that happens at different stages of this pipeline using shaders. As the shader functionality is very flexible, there are lots of possibilities of what developers can do with a shader: apply lighting to a 3D scene, change the texture on an object, change the position of an object.

(XNA / MonoGame pipeline from

(XNA / MonoGame pipeline from MSDN)

Summary: A shader is an operation that happens during the graphics rendering pipeline and can change the 3D model.

Earth Curvature Shader

We have written an Earth Curvature Shader that calculates the vertical drop (described above) based on the distance from the observer (mobile tablet) to the point in the 3D scene. As we chose to implement this as a shader, doing these calculations are quick: the visualisation screens can update 60 times a second to provide high quality animation and smooth motion. If it would help anyone, the implementation of the shader we are using can be found at VentusAR_TerrainShaderDiffuse.fx (please note: this is a .txt file, you will need to rename the shader file to be .fx)

Usage in VentusAR

We could never think of a time that users of VentusAR would not want to include Earth Curvature & Atmospheric refraction in their visualisations. So we have included it in the model every time the My View or Gallery is used (we don’t use it in the Fly Through, but as that evolves we may start to include it there). All visualisations produced with VentusAR 2.2 or later will include Earth Curvature and so be compliant with SNH guidelines.

VentusAR 2.3 Released!

We are pleased to announce the release of VentusAR v2.3 for Android, iPad (and associated portal updates).

Stitching_02For iPad and Android users this release includes many new features including:

  • Gallery Sync – an easy way to sync all data from the device to the portal
  • High Resolution Renders – Size the of the output Renders has increased to make higher resolution photomontages and photo wirelines
  • Import direct from external camera. In VentusAR 2.2 we added the ability to upload photography from external camera to the device via the portal, in order to streamline this process users can now import photos direct from the camera into the device.

For portal users this release include the following features:

  • Stitching together images to create panorama’s
  • Streamlining access to the national cumulative dataset

We recommend updating the new version of VentusAR to take advantage of the new features that have been introduced. On first launch after update, the device will migrate the gallery to the new format to allow the new gallery sync process to occur. Please ensure the device is online and able to connect to the VentusAR portal while this process completes.

See the full release notes for Android, iPad and the portal.

Minecraft Makes Wind Farm Development Projects Accessible

Press Release

Valid 00:01 April 1 2015 to 11:59am April 1 2015

New guidance for the visualisation of wind farms development understands that “stakeholder engagement is extremely important” and recognises that new developments have “considerable scope” for use as techniques are developed and presented.

In support of this guidance, Linknode today announced that development of a Minecraft version of its interactive visualisation and communication tools for wind farm development has reached preview stage.

MC - Ben Nevis

Minecraft Visualisation over Fort William to Ben Nevis (using Ordnance Survey Open Data – OS Terrain 50)

Minecraft is the most popular 3D world creation and exploration tool. Its use, up to now, has been primarily for gaming. However, its capabilities for planning assessment and visual impact assessment can now be readily exploited.

Crispin Hoult, CEO of Linknode explained: “This new development enables the visual impact of a project accessible on a PC, mobile phone or even a games console in the living room”. Hoult added, “with familiar devices and controls we can communicate information better and to a wide audience of interested stakeholders”.

MC - Sunrise over Ben Nevis

Minecraft Visualisation of a Sunrise Over Ben Nevis (using Ordnance Survey Open Data – OS Terrain 50)

Linknode’s business is the integration of real-world data for visualisation – typically in tablets for live photomontage visualisation with the flagship VentusAR software. The company realised that the underlying data and services can make the data available to a far wider audience, otherwise less engaged with the planning and development process.

In the future, SNH guidance for visualisation plans to embrace and incorporate all types of digital media, including real-time visuals and personalised access to data (after suitable testing and scrutiny).

The commercialisation and integrated product development is scheduled to take place over the next year to be released with a version of VentusAR on 1 April 2016.

Notes to Editors

Linknode is the creator of VentusAR – the tablet-based software that uses augmented reality to allow developers, planners and communities to see, in real-time, what a planned wind farm will look like in the landscape, from any location.

Minecraft: Available across multiple platforms, “Minecraft” is one of the most popular video games in history, with more than 100 million downloads, on PC alone, by players since its launch in 2009. “Minecraft” is one of the top PC games of all time, the most popular online game on Xbox, and the top paid app for iOS and Android in the US.

In September 2014 Microsoft Corp. announced it had reached an agreement to acquire Mojang, the celebrated Stockholm-based game developer, and the company’s iconic “Minecraft” franchise.