Date post: | 02-Jan-2016 |
Category: |
Documents |
Upload: | ross-branden-james |
View: | 222 times |
Download: | 4 times |
Beyond Visualisation in 3D Web GIS
James Milner
Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK WC1E 6BT
Supervisors: Kelvin Wong and Claire Ellul
@JamesLMilner
@JamesLMilner
How the project came about• UCL GIS MSc trip down to OS
• Initially performance testing for WebGL across devices (zzzz…)
• This was too similar to a previous project
• 3D Web GIS!
• May 29th - Meeting with David Capstick and Guy Heathcote
@JamesLMilner
Project aims To develop a plugin free 3D web GIS that implements:
o Selection
o Attribute retrieval
o Layer colouring
o 3D editing
o 3D buffering
o Distance and surface area measurement
“To assess the suitability of WebGL and Three.js with a spatial database backend as a platform for 3D web GIS.”
“To undertake a user study assess the merits and drawback of the developed system.”
@JamesLMilner
Data• Ordnance Survey 3D Data
• Had the choice between
Sheffield and Newcastle
• Esri Geodatabase
Feature NameFeature Geometry
TypeNumber of Features
Shapefile Size (kilobytes)
HeightedITNRoadNode Point 1470 64
HeightedITNRoadLink Line 2086 762
Vegetation MultiPatch 139 10,476
HeightedOSMM_TopoLine Line 8998 2,008
HeightedOSMM_TopoArea Polygon 21469 22,506
Walls MultiPatch 300 2,830
Roofs MultiPatch 300 1,968
SimpleBuildingHeights Polygon 5080 2,547
Bridges MultiPatch 3 132
Iconic_Buildings MultiPatch 4 1,784
@JamesLMilner
Database Setup• PostgreSQL / PostGIS
• Upload using FME Data Workbench
• Add auto-incrementing Big Serial for IDs
@JamesLMilner
The Web GIS Client• Nicknamed ‘Lacuna’ – ‘an unfilled space; a gap’
• Based off the UI’s of ArcGIS and QGIS to retain familiarity
• Responsive panes to handle different device sizes and resizing
@JamesLMilner
Convenience Functions
• Camera Options
• Pointer Helper
• Canvas Colour
• Axis Options
• Wireframe Toggle
@JamesLMilner
Single Selection• Pulls appropriate
• Convert screen coordinates into Cartesian
• Unprojected to 3D coordinate space
• Raycasting
• Hover and tap A
@JamesLMilner
Multi Selection• Multi Select (Marquee)
• Unprojection of coordinates
• Hold A and drag
@JamesLMilner
Attribute Retrieval• Attributes Retrieved through a button
• jQuery AJAX call
• Orders and puts into a nice table
• Highlighting in table and scene
@JamesLMilner
User Study• 10 participants assess various aspects of the GIS system
• Major issues were with load times
• System feedback is important
• Everything should be intuitive: make it obvious
@JamesLMilner
Issues• 3D Triangulation
• FME writes to WKT XYZ M
• PostGIS 3D support is hit and miss
• Interoperability is ‘hacky’
@JamesLMilner
Further Development• 3D Thematic Mapping ( Easy )
• Topological Model ( Hard )
• Texturing ( Medium )
• More spatial analysis tools (Varying)
@JamesLMilner
If I did it again• Geometry simplification (speed vs fidelity)
• A more robust approach to development
• Bootstrap might have aided responsive design
@JamesLMilner
Future plans for the project• Code is on GitHub… but it is a complete mess (sorry!)
• I’d really like to refactor it
• Three.js has had some interesting developments
• Have a persistent live demo on my site
• Dissertation PDF, Poster, GISRUK Draft Paper available
@JamesLMilner
What I am doing now…I currently work for Esri UK as a Developer Evangelist
I am aiming to a paper published in the GISRUK 2015 Conference Proceedings for the project
I run a website: loxodrome.co.uk
I have a storymap: loxodrome.co.uk/storymap