1. DEPARTMENT OF GEOMATIC ENGINEERING From 1m to the planet: mapping global population using Earth Observation: An Overview Jan-Peter Muller Professor of Image Understanding and Remote Sensing MODIS & MISR Science Team Member (NASA EOS Project) POLDER (ADEOSI/II), VEGETATION (SPOT4), GLI (ADEOSII) Workshop on Gridding Population Data Columbia University, New York Tuesday 2nd May 2000

2. DEPARTMENT OF GEOMATIC ENGINEERING Overview How can we use remote sensing to measure what is of relevance to global population mapping? Current Space Earth Observation platforms of relevance Exemplar 1: MODIS & VEGETATION for land surface BRDF/albedo for mapping large-scale urban structures Exemplar 2: ERS SAR interferometry for mapping urban land use and land use change at the sub-hectare scale Exemplar 3: IRS-1C for mapping urban land use for European cities (EU MURBANDY) Exemplar 4: IKONOS-2 for automated building detection and extraction (including height) Exemplar 5: POLDER & MISR for mapping aerosol sources Exemplar 6: MOPITT for mapping CO CEOS-IGOS Project proposal: Global mapping of urban population

3. DEPARTMENT OF GEOMATIC ENGINEERING Current Space Earth Observation platforms - a sample Moderate resolution (≥250m IFoV) –DMSP/OLS (1974- ) –CNES/EU VEGETATION (3/99-12/03) –NASDA ADEOS-POLDER (11/96-6/97) & ADEOSII-POLDERII (12/01-12/05) –NASA EOS/Terra+Aqua-MODIS (3/00-3/08) –NASA EOS/Terra-MISR (3/00-3/06) High resolution (≥5m IFoV) –LANDSAT-TM (5:1984-2000; 7:1999- ): 30(/15) m –ERS-SAR (1:1991-2000; 2:1995- ) –SPOT-XS/PA (1,2,3,4:1984- ): 20m/10m) –IRS-1C (1997- ): 5.8m Very High resolution (≤5m IFoV) –IKONOS-2 (≥9/99 ->)

4. DEPARTMENT OF GEOMATIC ENGINEERING How can we use remote sensing to measure what is of relevance to global population mapping? Currently civilian remote sensing can not be used to identify the location of people so have to infer anthropogenic activity from…. Land cover, land use and land use changes (including 3D) –Traditional remote sensing techniques employ classification of single or multiple (time series) of multi-spectral images »Problem is mixed signals from gardens & parks »Requires initial training sites to identify urban signals (very costly) –SAR (Synthetic Aperture Radar) interferometry (IfSAR) has strong reflection from “hard targets” such as buildings, roads or railways. However, visibility of objects is illumination angle dependent. IfSAR v. good for fragmentation. –BRDF/albedo related to land surface object geometry (e.g. urban, deforestation, desertification) and so exploit multi-angle RS signatures –Night-time lights only visible where and when cloud cover is absent and where signal sufficiently strong to be detectable & difficult to interpret –3D elevations with very high resolution images can be used to extract automatically individual 3D built settlement locations Anthropogenic activity - link to global change & human health –Aerosol PM (Particulate Matter) sources and sinks –Carbon Monoxide & Methane mapping

5. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 1: SPOT4 VEGETATION. Multi- angle/date BRDF retrieval Urban areas have high albedo due to man-made materials which enhance the “urban heat island” and pose the greatest threat to human health in the short-term Albedo determined through BRDF (Bi-Directional Reflectance Distribution Function) Three band colour composite of Red channel for July 1999 using semi-empirical kernel BRDF model (courtesy of M. J. Barnsley, UWS) –Nadir-equivalent (Red) –Geometric kernel (Green) –Volumetric kernel (Blue) Urban areas well identified at 1km Extension to global unlikely due to the high cost of the data

6. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 1 : MODIS BRDF-derived Nadir reflectance & Albedo. Global maps at 1km being produced every 16 days

7. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 2: Interferometric SAR for built environment area mapping: The UK LANDMAP Project to create a DEM and orthorectified LANDSAT, SPOT & ERS IfSAR Interferometric SAR excellent for mapping of Built environment –Potential down to resolutions of 30m ~ 0.3 hectares –Initial test over the British Isles as by- product of the LANDMAP project –Potential to map settlements where Night-light data is absent (developing world). –Can be done daytime and/or night- time –Not dependent on cloud-free conditions Urban areas are highly coherent especially over longer (inter- seasonal) temporal baselines Development can be tracked on an annual (or even shorter) timescale

8. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 2: False Colour composite and processed classified image of 3 band IfSAR data (Doll & Muller, ISPRS Congress 2000) Three band colour composite of Phase Coherence (Red) Amplitude (Green) Difference in Amplitude (Blue)

9. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 3: EU MURBANDY - application of traditional photo-interpretation to urban land use classification using IRS-1C for Vienna, AU. 20 EU cities selected for pilot project. http://murbandy.sai.jrc.it/

10. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 4: DSEM (Digital Surface Elevation Model) from simulated 1m spaceborne stereo-optical sensors with digital map data superimposed. Such DSEMs can be used to extract single buildings St Albans, UK ≤30m AGL (Red) ≈ AGL (Green) ≤-3m AGL (Blue

11. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 4: IKONOS-2 off-nadir 79cm image over the London Millennium Wheel (January 2000) ©Lockheed Martin

12. DEPARTMENT OF GEOMATIC ENGINEERING Examplar 4: IKONOS-2 derived building top height map over central London (©NPA 2000). Accuracy expected to be ≈1m Zrms)

13. DEPARTMENT OF GEOMATIC ENGINEERING Exemplar 5: Aerosol Mapping and Monitoring from POLDER @6.7km - example of DAILY air pollution (PM) maps over Mexico city

14. DEPARTMENT OF GEOMATIC ENGINEERING Example 5: MISR imaging geometry - multi-angular sampling for surface BRDF, aerosol retrieval and stereo Cloud-top heights & winds 9 pushbroom cameras 4 spectral bands 275m off-nadir, 250m nadir IFoV Swath≈380km Repeat time ≈3-9 days

15. DEPARTMENT OF GEOMATIC ENGINEERING Example of MISR 3-band multi-look (all 9 angles) imagery

16. DEPARTMENT OF GEOMATIC ENGINEERING Example MISR nadir vs 70ºf view of aerosols

17. DEPARTMENT OF GEOMATIC ENGINEERING Examplar 6: Examples of anthropogenic and natural urban- atmosphere interactions from MODIS, CERES & MOPITT

18. DEPARTMENT OF GEOMATIC ENGINEERING CEOS-IGOS Project proposal: Global mapping of urban population At a recent CEOS (Committee on Earth Observing Systems) WGISS (Working Group on Information Systems) meeting held at UCL, UK it was suggested that a new IGOS (International Global Observing System) project should be initiated along the lines of either the global Carbon Inventory or the global Forest Map project. This idea is currently being debated by email. IGOS are prototype very large-scale projects with active support from the space agencies who provide not only data but often funding for the generation of value-added products. It is not restricted to the academic community but includes government and the private sector Given the results of this workshop (and especially this session), should we push within CEOS to establish this project? Is there sufficient scientific justification even given the uncertainties?