Digital Glossop – Decimating Data

Next Friday (Friday 16th January 2015) will be the second year running for The Connected Communities Heritage Network Symposium, and the Digital building Heritage Group will be exhibiting work for the newly developed Digital Glossop mobile app which will be officially launched in April. This is part of a AHRC funded project (Grant Ref. AH/L008025/1, Title: Affective Digital Histories) led by the University of Leicester with a number of collaborators including De Montfort University. As well as the app other outputs being produced at the Digital Building Heritage Group for this project include transportable exhibition models incorporating various new digital technology’s that can be used to promote and explain the history of Glossop.

Glossop Arial (small)

Glossop is a post industrial town nestled on the western edge of the Peak district, famous for its cotton mills, it reached its peak production in 1880 but during the beginning of the 20th century the decline of cotton spinning forced most mills to close. The Digital Glossop Project is a way of documenting, archiving and telling the story of Glossop using modern digital technologies. Using a mobile application users will be able to see how the town has changed over the last century and a half with the use of digital reconstructions users can read, watch, and listen with various content collected from archival research. The project aims to change how people engage with their history, by creating the mobile app the heritage group can then continue to add to the online archive and upload more data to the app in the future.

In order to effectively show the towns changing urban structure over the last century and a half, five key dates were selected, 1880, 1950, 1960, 1970, and 2010. The dates were selected based mainly on the alteration or disappearance of the mills, for example 1880 was around the time when the mills production was at its peak and were at their largest, as production declined following 1880, the rest of the dates were selected when key buildings of the mills were demolished or altered, or in the case of 2010, burnt down. The key sources of information for recreating the mills in these periods were Ordinance Survey maps, arial images and existing buildings, although little information is available for the earliest date of 1880 using the earliest examples of images certainly helps paint a picture of what is would have looked like.Glossop Town Hall (small)

 Digitally recreating a whole town is a lot of work, particularly when it has five separate phases. The issue is further complicated when all the data created has to then be put into an app for users to be able to explore and use. We decided that in order to fit such a large amount of data into the app the digital modelling process would have to be divided into different areas of detail, and a method for decimating data was implemented. As the model was on such a vast scale it would take users a very long time to be able to explore the town through a real-time walkthrough method therefore we decided to replace this with carefully selected 360 degree street views at key areas throughout the town and mills, this would allow users to view the selected areas of the town in high detail either on or off site, and would not require as much computational power as the 360 degree street views consist of pre rendered images. This was labelled an area of ‘High Detail’ as the modelling would consist of high accuracy geometry and texturing.

High Detail (small)

 In order for users to understand and locate the street views the model needed to be displayed in context, however exploring the whole town even from an arial point of view would still take far too much computational power for most mobile devices. Therefore the use of digital animations were implemented to present an overview of each phase of the digital model, this again allowed users to see the mills in their entirety including textures and in the context of the towns layout. The level of modelling for this area was labelled ‘medium detail’, as a high level of detail would be necessary for the overall structure of the buildings but smaller details such as window frames could be replaced with flat images, as they would only be viewed from a distance and the smaller details would not have been visible.

Medium Detail (small)

 The final area was the ‘Low detail’ area, this was used to create 3D arial view maps, which would show the locations of the street views and could be tilted using the mobile device in order to gain a sense of the three dimensionality of the model. The low detail approach is the most effective for real-time processes, it uses mainly textures to create an effective model while keeping the geometry detail at a minimum. In the case of a building only the key openings such as doors, windows, and roof profile will be modelled, and pre rendered textures will be mapped on to the surfaces, the pre rendered textures creates the illusion of depth.

Low Detail (small)

It has been a great learning experience using digital technology in this field of community heritage, and a real challenge to develop methods of showing digitally reconstructed models so they could be used in a mobile application. The consistent balance of designing the digital models for specific viewing methods within the app has allowed me to look past the usual barrier when dealing with mobile devices of computational power. It will be of great interest to see how the Heritage group responds, and develops the app over the coming years, and as previous projects in the past have taught me there is never a firm end to working with community heritage groups.

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