network rail - esri uk annual conference 2016

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Stephen BrooksSenior EngineerSafety, Technical & Engineering: Buildings & Civils

https://uk.linkedin.com/in/stephenrbrooks

Evaluating & managing earthwork assets with GIS*(*without getting my shoes muddy)

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16,000 Route Km190,000 earthworks55,000 examinations

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Network Rail earthworks in numbers

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National aerial survey overview

Ortho FCIROrtho RGB Oblique

LiDAR DTM DSM

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Earthwork examinations

Earthwork inspections cost between £50 - £120 per five chain length

Each examiner will measure slopes ever so slightly differently

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Earthwork examinations

Some earthworks are more extreme than others

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Earthwork failures

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Earthwork remediation

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Earthwork failures: Harbury Landslip

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Harbury – One year later

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Exam question

Are we confident that we know where all our earthworks are and the associated geometry information is correct?

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Principles of methodology – adding heights to the points

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Principles of methodology – connecting the spot heights

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Principles of methodology – identify break points

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Principles of methodology – extract the slope info

Now repeat this process every 20m along the rail network(That’ll be 800,000 cross sections)

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Applying the methodology – Never Inspected

In September 2015 we had 36,000 sites that were never inspected.

By April 2016 we had less than 6,000

80% of the 30,000 records were removed without the need to set foot on track.

This involved analysing 150,000 cross sections and over 15m spot heights

Manual inspections of these sites would have cost in the region of £1.2m

We are now in the process of analysing all five chain length to verify examined geometries.

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Multiple cross sections - classified

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Multiple cross sections – filter results

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Manual versus automatic geometry extraction

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Revising the methodology

Cutting

(Slope height and angle is calculated along entire length)

Cutting >3m Cutting >3m Cutting >3m

Embankment <3m

‘flat’

Cutting <3m

‘flat’ ‘flat’ ‘flat’ ‘flat’

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Manual versus automatic geometry extraction

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Multiple cross sections – relating back to 5 chain lengths

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DTM vs automatic slope extraction

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Buffering the slope objects

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Never Inspected - Final Outputs

The never inspected analysis examined 150,000 cross sections and 15m spot heights.

We are currently rolling the methodology out nationally to verify presence of all earthworks regardless of inspection status. This involves: • Interrogating 47,000 raster tiles• More than 800,000 cross sections• Over 81 million spot heights

Once finished we will have a complete picture of all NRs earthworks assets, including detailed geometry, measured from a consistent perspective for the first time ever.

But what else could we do with the data?

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Conclusions

No one GIS system meets all requirements of such complex analysis• Collaborative use ArcGIS, ArcPro, ArcPy & FME

Always develop a methodology that:• is produced in conjunction with subject matter experts• produces output using language that SMEs understand• has flexible parameters and is scalable.• has systematic and logical data management• is well documented.

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Stephen BrooksSenior EngineerSafety, Technical & Engineering: Buildings & Civils

https://uk.linkedin.com/in/stephenrbrooks

Thank you