LYON, 28-30 JUNE 2000 6th EC-GIS WORKSHOP Earth Observation data as integrator tool in a town planning agency Hélène de Boissezon, Maylis Galaup, Stéphane

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


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


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


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


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


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


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


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


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


Simulation of future VHR satellite image

SPOT 5 THR image

2.5 m resolution in panchromatic channel

Advantages :

very good geometric precision


illustration scale: 5.000e

LYON, 28-30 JUNE 2000


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



LYON, 28-30 JUNE 2000


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


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


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


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


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


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)


LYON, 28-30 JUNE 2000


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)


LYON, 28-30 JUNE 2000


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)


LYON, 28-30 JUNE 2000


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


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


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


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

Documents

LYON, 28-30 JUNE 2000 6th EC-GIS WORKSHOP Earth Observation data as integrator tool in a town planning agency Hélène de Boissezon, Maylis Galaup, Stéphane