lyon, 28-30 june 2000 6th ec-gis workshop earth observation data as integrator tool in a town...
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LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Earth Observation data as integrator tool
in a town planning agency
Hélène de Boissezon, Maylis Galaup, Stéphane Dupuy
SCOT
Services et Conception de systèmes en Observation de la Terre
Ramonville, France
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
General background on geographical data managed by cities
”Technical” and “Tactical” levels are well defined in urban GIS
technical data, cadastral data, aerial photographs
Creation of data at ”Strategic” level often require heavy processing
• aggregation and generalisation of technical data
• problems of heterogeneity
New opportunities with the arrival of VHR satellite images
Three main levels in urban information systems
Tactical
Technical
Thematic layer 1:25 000 to 1:10 000
Urbanism document 1:5 000
Basic maps 1:2 000 to 1: 500
Strategic
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Description of tasks managed by cities
cadastral data, patrimony and public service management
ENVIRONMENTALMANAGEMENT
TERRITORIALMANAGEMENT
TRANSPORTATIONMANAGEMENT EQUIPMENT AND
INFRASTRUCTURE MAINTENANCE
URBANPLANNING
networks facilities maintenance
traffic optimisation
real-time control
risk analysis
measures for limiting pollution
land use planning
Five main domains in urban information system
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Potential utilisation of EO data
Two domains of activity demand more tactical or strategic data with important needs in
• global, regular, historical geographical information,
• information processes able of mixing statistical and geographical data, and modelling evolutions
environmental management
urban planning
Particular use of GPS data for traffic control
Potential use of EO data for the whole information system
• integrating role
• communication medium
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Urban planning in France
Urban planning
• methods used to influence future geographical distribution of activities on territory, for more rational land use organisation
• more and more complex task, with increasing responsibilities
• work performed at regional scale, not only city level New territory management law (LOADDT)
• association of economic/social, urban/rural areas in sustainable way
• redefinition of local authorities territories
• only three regrouped administrative units : community of municipalities, community of agglomeration, urban community
Increasing work at “community” level, and not only “city” level
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Practical study on Toulouse agglomeration
Increasing requirements in global geographic information in the local town planning agency (AUAT)
Requirements for geographic information at STRATEGIC level for Master Plan revision, environmental studies, “Territorial Coherence Scheme” and “Regional Schemes of Territory Management” (LOADDT).
Main problems encountered, solutions brought by EO
Large area of interest: 40 x 40 km², with 60 municipalities
Land use data are frequently not self-consistent, not regularly updated
Zoning documents integrate regulation information, actual and planned land cover/land use
Aerial photographs do not cover the whole AUAT territory
EO data should provide exhaustive updated land cover information
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Input data
For answering town planning agency needs at STRATEGIC level
The most precise EO data commercially available in 1999 have been used :
IRS 1C Panchromatic image at 5m resolution
Spot Xi Multispectral image at 20 m resolution
Merging of data for getting multispectral image at 5m resolution
For analysing city council requirements at STRATEGIC level
Simulations of future Spot5 images have been used :
Spot5 THR Panchromatic at 2.5 m resolution
Spot5 XS Multispectral at 10 m resolution
Merging of data for getting multispectral image at 2.5 m
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Selection of satellite images
Panchromatic IRS Image
5 m resolution
Black and White
date: 20th March 99
Advantages :
good precision allowing restitution at 25.000e
full image:70x70 km²
illustration scale : around 75.000 e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Selection of satellite images
SPOT Xi image
20 m resolution
4 channels: G, R, PIR, MIR
date : 20th March 99
Advantages :
very good radiometric information allowing automatic classification
full image 60x60 km²
illustration scale : around 75.000 e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Simulation of future VHR satellite image
SPOT 5 THR image
2.5 m resolution in panchromatic channel
Advantages :
very good geometric precision
full image 60x60 km²
illustration scale: 5.000e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Simulation of future VHR satellite image
SPOT 5 THR+XS image
2.5 m resolution in panchromatic channel
merged with 10 m resolution in multispectral channels
Advantages :
very good geometric precision and radiometric information allowing automatic classification
full image 60x60 km²
illustration scale: 5.000e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Technical work performed on satellite images
Main technical orientations for image processing in the pilot project
• production of information about land occupation, self consistent with definitions and nomenclatures used by AUAT
• targeted scales : 1:10.000 mainly, and 1:25.000
• working area covering the whole area of interest of AUAT (40x40km²)
• priority to automatic image processing for reliable, reproducible, rapid and cost-effective methods and products
• regular evaluation and feed-back on results by AUAT and Toulouse City Council
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Technical work performed on satellite images
Pre-processing:
Geometric correction of Spot Xi and IRS Pan images (Lambert 3 projection)
Merging of images Pan and Xi
creation of Pan+Xi image with 4 channels, 5 m resolution
Creation of “Natural colours image” :
Creation of artificial Blue channel by linear combination of Green and Near Infra Red channels
image similar to an aerial photograph
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOPProduct « Natural colour
image »
IRS+Spot image in natural coloursScale 1:25.000 5 m resolution
4 channels : G, R, NIR, MIR
projection: Lambert 3
Advantage :
- easy interpretation by non skilled users
- large coverage
- fully operational
Professional use:
- decision making at strategic level
- communication tool for Master Plans, urban projectsillustration size :42 x 42 km²
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Creation of the « Physical land occupation map »
Calculation of parameters characterising urban structures
texture : characterisation of urban structures
variance : extraction of large buildings with strong reflectance
Segmentation and classification of image
identification of homogeneous regions of the image (radiometry, texture and variance)
classification of regions into 25 initial radiometric classes
Characterisation of classes
manual regrouping into 7 land occupation classes
Quality control and manual corrections
suppression of some radiometric confusions such as : light bare soils and urban areas, commercial buildings roofs and bare soils, building sites and urban areas, ...
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Product « Physical land occupation map »
Information layer« physical land occupation map » at 25.000e scale
The 7 final classes
• built-up areas : light pink• large buildings : red• individual houses : purple• woods : dark green• vegetation : yellow• bare soils : brown• water : blue
Professional use:Minor interest for users (nomenclature not compatible)
illustration scale 1:75.000
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Creation of derived information plans by aggregation
Method
zoning by aggregating entities with inter-distance criterion
use of GIS functions (positive et negative buffers )
entirely automatic processing applied to the “physical land occupation” layer
Creation of the « Agglomerated urban areas »
application of 200 meters distance to built-up areas (Eurostat and INSEE criterion)
delimitation of Toulouse urban physical agglomeration
Creation of the « Aggregated vegetation areas »
selection of vegetated areas with surface greater than 0.5 ha
application of 50 meters distance to vegetation areas
delimitation of the green areas on Toulouse agglomeration
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Product « Agglomerated urban areas »
Derived information layer«agglomerated urban areas» at 25.000e scale
in pink : actual physical extent of the urban agglomeration
Advantages:- single zoning showing physical extent of agglomeration at a given date - can be adapted to other towns
Professional use:
- comparison of planned / actual housing (Master Plan revision)
illustration scale: 200.000e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Product « Agglomerated urban areas »
Derived information layer«agglomerated urban areas» at 25.000e scale
in pink : actual physical extent of the urban agglomeration
Advantages:- single zoning showing physical extent of agglomeration at a given date - can be adapted to other townsProfessional use:
- comparison of planned / actual housing (Master Plan revision)
illustration scale: 200.000e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Product « Aggregated vegetation areas »
Derived information layer« aggregated vegetation areas » at 25.000e scale
in green : actual extent of the green areas and woods
Advantages:- mapping of all vegetation areas (private and public) - identification of continuous green areas (“green belt”)
Professional use:- living environment studies
- comparison of planned / actual green areas (Master Plan revision)
illustration scale: 200.000e
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Technical work performed on simulated Spot5 imagesPre-processing and processing steps : the same as for satellite image
Pre-processing (geometry, merging of 2.5 m and 10m resolutions)
Creation of “Natural colours image”
Calculation of parameters characterising urban structures
Segmentation and classification of image
creation of the physical land occupation map
Remark : results similar with classification per pixel
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Creation of derived information plans on census block basisMethod for census blocks characterisation
Calculation of statistical parameters per block (major class, % of classes, etc.)
Crossing of
land occupation
and
census blocks
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Product « Characterisation of urban blocks »
Characterization of land occupation per block at 10.000e
the color of the block indicates the percentage of artificial area
Advantages:- mapping of land occupation inside blocks, either private and public - identification of sealed/unsealed areas-information reproducible each yearProfessional use:- water runoff studies - environmental studies- living environment studies
LYON, 28-30 JUNE 2000
6th EC-GIS 6th EC-GIS WORKSHOPWORKSHOP
Conclusion and perspectives
Better access to VHR satellite images in the near future
Conditions of success for VHR satellite imagesEO data must not be considered as final productEasy and efficient integration into urban and regional data bases:
communication mediumintegrator toolspatialisation of statisticscorroboration of other data
Two critical issues:automatic processing will it be possible?sufficient geographical coverage (swath) ?
Launch Resolution Swath Processing
I konos end 1999 11 kmQuickBird end 2000 1m, 4m 22 km Manual, Automatic ?OrbView early 2001 8 km
Spot5 early 2002 2.5m, 5m, 10m 60 km Automatic