Product tip – Running nationwide calculations in TRACC
Find out how we used a nationwide TRACC calculations to look at conference venue accessibility based on drive times
On a recent visit to the National Exhibition Centre (NEC) in Birmingham, we noticed adverts claiming the exhibition centre offers unrivalled accessibility by road, rail and air. In fact they state that 75% of the UK’s population live within a three-hour travel time of NEC Group venues, thanks to two major rail stations, an international airport and excellent road links. http://www.necgroup.co.uk/about-us/our-locations
We decided to use our market leading travel time analysis tool TRACC to test these claims by running a nationwide calculation. We looked at the NEC, ExCeL in London and Manchester Central Convention Centre (GMEX) in Manchester, and calculated how many people could access these venues by driving or public transport within 3 hours.
You can see clearly from the drive time maps below that the NEC is the most accessible for a greater number of people within the 3 hour travel time. Based on census information, approximately 49,134,466 people can access the NEC in under a 3 hour drive in comparison to 43,773,622 for ExCeL and 30,260,281 for GMEX.
When we looked at public transport links, the difference was less obvious. The NEC is accessible for approximately 22,899,626 people within a 3 hour travel time, but ExCeL was slightly more at 23,037,134 (GMEX was 18,006,802). However, you could argue that the NEC is still the most accessible for people across the country given that the majority of people highlighted in the ExCeL calculation are based in London. So these nationwide calculations on TRACC would seem to support the NEC’s claims about accessibility, certainly in terms of drive times.
Tips for running a nationwide calculation
To make your calculation more efficient its worth considering some of the parameters in TRACC that are designed to make these large calculations run as smoothly as possible:
Return Accessible Results Only: This will help to speed up your calculation by only compiling results where journeys can be completed within your parameters. Any origin points that are ‘not accessible’ will not be returned in your results set. This will speed up the processing time of your calculation allowing you to assess accessibility over a large area more quickly.
Utilise Road/PT Network Envelope: These parameters help to restrict the amount of data that is used in your calculation. By activating the ‘Envelopes’ TRACC will create a buffer of data (either Road Network or PT Stops) around the furthest extent of Origin and Destination points- and disregard any excess. This will speed up your large calculation as only the necessary data is being processed.
Max number of first stops: This will use only the closed X number of stops from each origin point in a Public Transport calculation. This will limit the journey options available and so will speed up the processing in your large calculation. Be aware that this may skew results if the value is set too low.
Normalise Road Network: If you don’t mind losing a little bit of accuracy due to the size of your calculation why not try using the Normalise Road Network option? This simplifies the road network by removing any curvature- straightening out the road. The calculation with still use the actual distance of the road- but considers one long link, rather than lots of small segments. This can make a huge difference to the speed of the calculation, especially if you are using a highly-detailed road network such as the ITN+UP or OS Highways.
** These National calculations will only be possible using the 64-bit version of TRACC, and performance will depend of the capabilities of your machine.