Collaborative Tool for Collecting Reference Data on the Density of Constructed Surfaces Worldwide

Chris ElvidgeNOAA-NESDIS National Geophysical Data Center

325 Broadway, Boulder, Colorado 80305 USATel. 1-303-497-6121

Email: chris.elvidge@noaa.gov

Ben TuttleCooperative Institute for Research in Environmental Sciences

University of Colorado, Boulder, Colorado USA andDepartment of Geography, University of Denver, Denver, Colorado USA

Paul SuttonDepartment of Geography

University of Denver, Denver, Colorado USA

September 10, 2009

Constructed SurfacesConstructed Surfaces Roads Roads BuildingsBuildings VehiclesVehicles SidewalksSidewalks

Collectively referred to as constructed surfaces or impervious surface area (ISA).

Constructed SurfacesConstructed Surfaces People everywhere build for shelter, commerce People everywhere build for shelter, commerce

and transportation.and transportation. Impervious materials are used in buildings to Impervious materials are used in buildings to

keep out water and enhance durability. keep out water and enhance durability. Roads are paved with impervious materials such Roads are paved with impervious materials such

as asphalt and cement for their ability to shed as asphalt and cement for their ability to shed water, provide a smooth driving surface, and ease water, provide a smooth driving surface, and ease of maintenance. of maintenance.

There are large gradients in the density of There are large gradients in the density of constructed surfaces, ranging from zero to 100%.constructed surfaces, ranging from zero to 100%.

These gradients track gradients in the density of These gradients track gradients in the density of population, economic activity and resource population, economic activity and resource consumption.consumption.

How Constructed Surfaces Impact How Constructed Surfaces Impact the Environmentthe Environment

FloodingFlooding Reduced groundwater rechargeReduced groundwater recharge Urban heat islandsUrban heat islands Urban pollutants swept into waterways Urban pollutants swept into waterways

reduce surface water qualityreduce surface water quality Intense water discharges tends to incise Intense water discharges tends to incise

stream banksstream banks Habitat loss and fragmentationHabitat loss and fragmentation Linked to reductions in biodiversityLinked to reductions in biodiversity

How Constructed Surface Density How Constructed Surface Density Grids Are UsedGrids Are Used

Flood predictionFlood prediction Design of storm drainage systems (sizing Design of storm drainage systems (sizing

and placement)and placement) Evaluating human impacts on ecosystemsEvaluating human impacts on ecosystems As a measure of the human ecological As a measure of the human ecological

footprintfootprint As an indicator of the spatial distribution of As an indicator of the spatial distribution of

resource consumptionresource consumption

How Constructed Surface Area How Constructed Surface Area Density Grids are madeDensity Grids are made

Ground based surveys – time consuming and covering small Ground based surveys – time consuming and covering small areas.areas.

Measurements from high spatial resolution airborne or Measurements from high spatial resolution airborne or satellite imagery – expanded coverage from ground surveys satellite imagery – expanded coverage from ground surveys – but still limited in spatial extent.– but still limited in spatial extent.

Spectral analysis of moderate resolution satellite imagery Spectral analysis of moderate resolution satellite imagery (e.g. Landsat). Calibrate with high resolution imagery. Can (e.g. Landsat). Calibrate with high resolution imagery. Can produce grids of extended geographic areas – but no global produce grids of extended geographic areas – but no global product produced to date.product produced to date.

Model from coarse resolution data sources such as Model from coarse resolution data sources such as nighttime lights or population count. Calibrate using a nighttime lights or population count. Calibrate using a subset of measurements made from higher spatial subset of measurements made from higher spatial resolution imagery.resolution imagery.

Year 2000 Global Constructed Year 2000 Global Constructed Surface Area Density GridSurface Area Density Grid

Paper: http://www.mdpi.com/1424-8220/7/9/1962Paper: http://www.mdpi.com/1424-8220/7/9/1962 Data: http://www.ngdc.noaa.gov/dmsp/download_global_isa.htmlData: http://www.ngdc.noaa.gov/dmsp/download_global_isa.html Nominally for year 2000Nominally for year 2000 Input 1: Radiance calibrated DMSP nighttime lights for year 2000 Input 1: Radiance calibrated DMSP nighttime lights for year 2000

(30 arc second grid) (30 arc second grid) Input 2: Landscan 2004 population count (30 arc second grid)Input 2: Landscan 2004 population count (30 arc second grid) Model calibrated using 30 meter resolution ISA densities of the Model calibrated using 30 meter resolution ISA densities of the

USA derived from year 2000 Landsat (U.S. Geological Survey) USA derived from year 2000 Landsat (U.S. Geological Survey)

USGS %ISA For Year 2000USGS %ISA For Year 2000

Radiance Calibrated DMSP Radiance Calibrated DMSP Nighttime Lights For Year 2000Nighttime Lights For Year 2000

Population Count For Year 2004Population Count For Year 2004DOE LandscanDOE Landscan

Modeled ISA From Lights and PopulationModeled ISA From Lights and Population

NGDC versus USGS %ISANGDC versus USGS %ISA

Global Nighttime LightsGlobal Nighttime Lights

Global Population DensityGlobal Population Density

Landscan U.S. Department of EnergyOak Ridge National Laboratory

Global % ISA Year 2000Global % ISA Year 2000

Year 2000 Top Twenty CountriesYear 2000 Top Twenty CountriesCOUNTRY ISA km2 Population (Landscan 2004) ISA per Person (m2) China 87,182 1,292,548,864 67.4United States 83,881 282,575,328 296.8India 81,221 1,058,349,824 76.7Brazil 17,766 177,885,936 99.9Russia 17,135 138,947,840 123.3Indonesia 16,490 230,000,208 71.7Japan 13,990 122,192,928 114.5Mexico 11,854 103,608,488 114.4Canada 11,295 32,022,750 352.7Pakistan 10,666 150,465,168 70.9France 9,537 59,497,124 160.3Bangladesh 8,878 140,275,504 63.3Germany 8,500 82,406,312 103.1Italy 8,294 56,528,760 146.7Nigeria 7,668 125,118,728 61.3United Kingdom 7,576 58,926,004 128.6Spain 7,037 39,481,976 178.2Iran 6,949 66,604,152 104.3Vietnam 5,981 81,249,416 73.6Egypt 5,745 75,240,640 76.4Thailand 5,556 64,418,264 86.2Philippines 5,428 80,687,360 67.3

Shortcoming of the Year 2000 GridShortcoming of the Year 2000 Grid

The model was calibrated using 30 meter The model was calibrated using 30 meter resolution ISA densities of the USA derived resolution ISA densities of the USA derived from Landsat (U.S. Geological Survey). from Landsat (U.S. Geological Survey).

It is likely that there is variation in the It is likely that there is variation in the relationship between ISA density, lights relationship between ISA density, lights and population in other parts of the world. and population in other parts of the world.

Plans to Build a Better Product Plans to Build a Better Product

NGDC recently completed an improved radiance calibrated NGDC recently completed an improved radiance calibrated nighttime lights image for 2006. A new collection for nighttime lights image for 2006. A new collection for radiance calibrated nighttime lights is planned for 2009-10.radiance calibrated nighttime lights is planned for 2009-10.

U.S. Department of Energy made substantial improvements U.S. Department of Energy made substantial improvements in the Landscan 2006 and 2007 products.in the Landscan 2006 and 2007 products.

Use reference data on the density of constructed surfaces Use reference data on the density of constructed surfaces collected from high resolution imagery from a wide range of collected from high resolution imagery from a wide range of locations and settings.locations and settings.

High spatial resolution satellite imagery is available for many High spatial resolution satellite imagery is available for many urban areas around the world from systems such as IKONOS urban areas around the world from systems such as IKONOS and Quickbird.and Quickbird.

It would be expensive and time consuming to select, It would be expensive and time consuming to select, purchase and analyze large numbers of high resolution purchase and analyze large numbers of high resolution satellite images.satellite images.

Could we collect reference data using the high spatial Could we collect reference data using the high spatial resolution imagery available for view in Google Earth? resolution imagery available for view in Google Earth?

Components of Gridded Point Count Components of Gridded Point Count Collection System For Use of Google Collection System For Use of Google

Earth Base ImageryEarth Base Imagery Google Earth Plug-in.Google Earth Plug-in. Google Earth Application Programming Interface (API) .Google Earth Application Programming Interface (API) . MySQL database used to record the data.MySQL database used to record the data. KMZ for DMSP nighttime lights image.KMZ for DMSP nighttime lights image. Interactive Data Language program for generating corner Interactive Data Language program for generating corner

points of 30 arc second grid cells.points of 30 arc second grid cells. Scripting done in javascript and php.Scripting done in javascript and php. Current version is at: Current version is at:

http://www.ngdc.noaa.gov/dmsp/imaps/isamapper/http://www.ngdc.noaa.gov/dmsp/imaps/isamapper/

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Google Earth Tool Google Earth Tool

Preliminary Results Preliminary Results

SummarySummary A system for visual collection of gridded A system for visual collection of gridded

point counts of constructed surface density point counts of constructed surface density using high spatial resolution imagery using high spatial resolution imagery available in Google Earth has been available in Google Earth has been developed.developed.

The system is designed to allow The system is designed to allow contributions from a widely distributed contributions from a widely distributed open set of analysts. open set of analysts.

The system will make it possible to produce The system will make it possible to produce a substantially improved global constructed a substantially improved global constructed surface density grid.surface density grid.

Accessing the high resolution imagery in GE Accessing the high resolution imagery in GE saves the project from the costs of saves the project from the costs of selecting, purchasing, storing, organizing selecting, purchasing, storing, organizing and accessing high resolution color imagery and accessing high resolution color imagery from around the world. from around the world.

Improvements to the system are being Improvements to the system are being discussed (tutorial, randomization of grid discussed (tutorial, randomization of grid point selections, additional cover type point selections, additional cover type categories).categories).

The system could be modified for other The system could be modified for other types of gridded point count collections types of gridded point count collections (e.g. tree cover).(e.g. tree cover).