1 image et ville 7 th ec-gi & gis workshop – 13-15 june 2001 – potsdam the use of « image...

1

ImageEt Ville

7th EC-GI & GIS WORKSHOP – 13-15 June 2001 – Potsdam

THE USE OF « IMAGE » IN GEOGRAPHICAL THE USE OF « IMAGE » IN GEOGRAPHICAL

INFORMATION MARKET : RESULTS OF AN INQUIRY INFORMATION MARKET : RESULTS OF AN INQUIRY

ON THE END-USERS’ NEEDS ON THE END-USERS’ NEEDS

IN URBAN STUDIESIN URBAN STUDIES

Anne Puissant1 & Christiane Weber2

Laboratoire Image et Ville UMR 7011 CNRSUniversité Louis Pasteur, Strasbourg

[email protected] PhD Thesis2 Researcher

2

ImageEt Ville


PLAN

1. GI CONTEXT

2. OBJECTIVES

3. FRAMEWORK OF THE STUDY

4. THE THREE STEPS OF THE SURVEY

5. DATA TREATMENTS

6. INVESTIGATED ORGANIZATIONS

13. CONCLUSION

7. USERS OF GIS

8. APPLICATIONS IN GIS

9 . USES OF IMAGE DATA

10. NON- USE OF SATELLITE IMAGES

11. NEEDS IN IMAGE DATA FOR END-USERS

12. USERS OF SATELLITE IMAGES

RESULTS

3

ImageEt Ville


The Geographical Information market, a sector in full expansion ?The Geographical Information market, a sector in full expansion ?

1. GI CONTEXT

Development of the Information Society

- Global Positioning System (GPS)

- Numerical aerial or satellite images

Development of digital cameras digital orthophoto image

Recent and announced launchings of earth observation satellites with a spatial resolution of one meter (Ikonos, Orbview…)

- Geographical Information System (GIS)

- Development of Internet and online technologies

Multiplication of available multi-source data on the market

Fast changes with new communication and information technologies

Changing behaviours of producers and users of GI ?

4

ImageEt Ville


2. OBJECTIVES

Lack of information on the role of images as potential source of informationand their impacts on the practice of users

Realization of a survey in France and some European countries

To assess the role and the place of images (aerial photographs and satellite images) in the practice of users

To identify the end-users’ needs in terms of image data relevant for urban applications

To identify urban objects and characteristics useful for urban applications

Objectives of the survey :

5

ImageEt Ville


3. FRAMEWORK OF THE STUDY

Which users must this component satisfy in urban areas ?

For what kind of applications ?

What are the characteristics of the information required (spatial, spectral, geometrical requirements…) and for what kind of services (programming, storage, time of production… ?

Questions :

Part of a wider research (PhD Thesis under progress on “Potentialities of VHR images to extract urban features”)

Continuity of the spatial programme of the CNES

Specifications of the « high optical resolution » component of PLEIADES

6

ImageEt Ville


4. THE THREE STEPS OF THE SURVEY

The target population

Actors working on urban areas : local authorities (city councils, urban communities), public administration services, planning agencies, independent structures such as network management agencies…

Answer rate : 9 %

Total answer rate : 15 %

STEP 2 : Workshop

“Which scales for which needs : utility of large scale GI for urban studies”(Strasbourg, January 30 2000)

STEP 3 : Interviews

25 interviews from February to October 2000 near local authorities

(CEO Study leaded by SCOT (1997) : 6 %)

Sent between June and October 1999 by post and e-mail to more than 200 French and 150 European organisations

STEP 1 : Questionnaire

7

ImageEt Ville


5. DATA TREATMENTS

SURVEY :Questionnaire - Workshop - Interview

"Closed" questions "Opened" questions

Users group

Structuring analysisHierarchical classification

Users behaviour

Factorial analysis Exploratory statistics

Encoded data

Working Hypothesis

8

ImageEt Ville


6. INVESTIGATED ORGANIZATIONS

- seven categories of organizations

- More than 60 % of local authorities

9

ImageEt Ville


7. USERS OF GIS

Three users categories according to : - their type of organizations - their period of activity in GIS - the softwares used

GROUP 1 : Urban Communities and Cities of more than 100,000 inhabitants with a GIS for more than 5 years

using Geocity, Apic, Star, and Arc View

GROUP 2 : Public Administration Services, regional and general councils with a GIS for less than 5 years

using only Mapinfo

GROUP 3 : Planning Agencies and cities of more than 50,000 inhabitants with a GIS for less than one year

using Geoconcept or Star

10

ImageEt Ville


8. APPLICATIONS IN GIS

Working Hypothesis n°1 :

“Today GIS are only used as simple managing and structuring tools”

GIS : a data management tool for most people (operational and vertical levels)

but also a tool for concrete applications (tactical level)

Puissant 2000, inspired by Chevalier 1990

11

ImageEt Ville


9. USES OF IMAGE DATA (1)

Use of digital ORTHOPHOTO image :

By more than half of the investigated organizations

Use of SATELLITE IMAGES :

By approximately third of the organizations


“The end-users use image data in a GIS as a simple communication support”

12

ImageEt Ville


9. USES OF IMAGE DATA (2)

These data are not in competition but rather complementary, in terms of applications and scales of output documents

* Without Ikonos

*

13

ImageEt Ville



“The non-use of satellite images

in GIS is due to the inadequacy

of their spatial resolution”

10. “NON-USE” OF SATELLITE IMAGES

14

ImageEt Ville


11. NEEDS IN IMAGE DATA FOR ENDS-USERS

- To limit the shadow areas

- Uniformity of radiometry

- Small volume of data

- Delay to obtain products

Expectation deducted from the problems encountered by the users of digital orthophoto image :

- Value-added products (land cover cartography…)

- Better resolution (< 5 m and/or < 1 m in dense areas)

- Facility of compression

- Coherent nomenclature with land cover plan (Master plan)

In a decreased order :

15

ImageEt Ville


12. USERS OF SATELLITE IMAGES

Four users categories according to their type of organisations, applications with image, problems and expectations

GROUP 1 : - urban communities already using image for the cartography of green areas, impermeable surfaces…

- expecting a resolution below one meter in dense urban areas and nomenclature adapted to the land cover plan

GROUP 2 : - urban communities which do not use images but where reflections are under progress

GROUP 3 : - planning agencies which use images for land cover cartography and for a complementary view of their territory. - problems with automatic extraction and interpretation of data

GROUP 4 : - organisation without images (public administration services, cities below 50,000 inhabit.)

- expectation of resolution lower than 5 m and value added products

16

ImageEt Ville


13. CONCLUSION (1)

Significant facts :

Tendency of MULTI-TASK and MULTI-USER GIS

Most of the applications in urban areas concern :

- management of data (operational level)

- urban planning (tactical level) 1:200 to 1:10 000

VHR imagepotentialities

17

ImageEt Ville


To play a role as a communication support, satellite image will have :

- to propose natural colors products, directly interpretable by non-specific users

- to set uniform radiometry

- to reach accurate geometrical details at least one meter resolution

To be used as an information source, satellite image will have :

- to be available as value-added product allowing an updating at least per year according to a user defined limit, at a reasonable cost ;

- to cover large territories

13. CONCLUSION (2)

For a “raw” image use, the users will have to lay out :

- automatic extraction and compression procedures of the images

- object nomenclature adapted to the land cover plan (Master Plan)

- products where shadow effects are limited

18

ImageEt Ville


1 image et ville 7 th ec-gi & gis workshop – 13-15 june 2001 – potsdam the use of « image...

Documents