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15 / Nov / 2017 Training Module A2 Session 3
TrainerKhaled Mashfiq
Searching, Exploring and Gathering Geospatial Data
In partnership with Introduction to the Use of Geospatial Information Technology for Drought Risk Management
Phnom Penh, Cambodia14-17 November, 2017
2
Outline
Data Characteristics
Data Sources
Purpose of Geodata
Data Download
3
Data Characteristics
Satellite Imagery
4
The most common characterization of satellite imagery results from:
• Diverse acquisition date/time
• Sensor type
• Scene size
• Resolutions
• Data format
Data Characteristics
The spatial resolution specifies the pixel size of satellite images covering the earth surface
Very High/ High spatial resolution: 0.25 - 4 m
Medium spatial resolution: 4 - 30 m
Low spatial resolution: 30 - > 1000 m
5
No. Sensor Name Sensor Type
Resolution(m)
PAN MS
1 GEO EYE-1 Optical 0.41 1.7
2 WORLDVIEW-1 Optical 0.45 -
3 WORLDVIEW-2 Optical 0.46 1.8/2.4
4 WORLDVIEW-3 Optical 0.31 1.24
5 IKONOS-2 Optical 1 4.0
6 CARTOSAT-2A Optical 1 -
7 SPOT 6&7 Optical - 1.5
8 CARTOSAT-1 Optical 2.5 -
9 FORMOSAT-2 Optical 2 8.0
10 Quickbird-2 Optical 0.6 2.4
11 SPOT-5 Optical 2.5 5/10/20m
12 TopSat Optical 2.9 5.7
13 SPOT 1 to 3 Optical 10 20/10m
14 SPOT-4 Optical 10 20/10m
15 Terra- ASTER Optical - 15/30/90
16 DEIMOS/UK-DMC2 Optical - 22.0
17 Landsat-7 ETM+ Optical 15 30.0
18 Landsat-5 TM Optical - 30.0
19 Terra/Aqua- MODIS Optical 250 – 10000.5m 5m 25m 50m
What is Spatial Resolution?
Swath Width 6
No. Sensor Name Sensor Type
Resolution(m) Swath Width (km)PAN MS
1 GEO EYE-1 Optical 0.41 1.7 15
2 WORLDVIEW-1 Optical 0.45 - 16
3 WORLDVIEW-2 Optical 0.46 1.8/2.4 16.4
4 WORLDVIEW-3 Optical 0.31 1.24 13.1
5 IKONOS-2 Optical 1 4.0 11
6 CARTOSAT-2A Optical 1 - 10
7 SPOT 6&7 Optical - 1.5 60
8 CARTOSAT-1 Optical 2.5 - 30
9 FORMOSAT-2 Optical 2 8.0 24
10 Quickbird-2 Optical 0.6 2.4 16.5
11 SPOT-5 Optical 2.5 5/10/20m 60
12 TopSat Optical 2.9 5.7 17/12.0
13 SPOT 1 to 3 Optical 10 20/10m 60
14 SPOT-4 Optical 10 20/10m 60
15 Terra- ASTER Optical - 15/30/90 60
16 DEIMOS/UK-DMC2 Optical - 22.0 Up to 600
17 Landsat-7 ETM+ Optical 15 30.0 185
18 Landsat-5 TM Optical - 30.0 185
19 Terra/Aqua- MODIS Optical 250 – 1000 2330
Swath width refers to the strip of the Earth’s surface from which data are collected by a satellite
What is Spectral Resolution? 7
No. Sensor NameResolution(m) Bands
PAN MS PAN MS
1 GEO EYE-1 0.41 1.7 1 -
2 WORLDVIEW-1 0.45 - 1 -
3 WORLDVIEW-2 0.46 1.8/2.4 1 8 (R,G,B,NIR,RE,Y,NIR2)
4 WORLDVIEW-3 0.31 1.24 1
8 (Coastal, R,G,B,NIR,RE,Y,NIR2), 8 SWIR bands, 12 CAVIS
Bands
5 IKONOS-2 1 4.0 1 MS (RGB-NIR)
6 CARTOSAT-2A 1 - 1 -
7 SPOT 6&7 - 1.5 1 4(R,G,B,NIR)
8 CARTOSAT-1 2.5 - 1 -
9 FORMOSAT-2 2 8.0 - 4(RGB-NIR)
10 Quickbird-2 0.6 2.4 1 MS (RGB-NIR)
11 SPOT-5 2.5 5/10/20 1 3(R,G,NIR)
12 TopSat 2.9 5.7 1 3(R,G,B)
13 SPOT 1 to 3 10 20/10 1 3(R,G,NIR)
14 SPOT-4 10 20/10 1 3(R,G,NIR)
15 Terra- ASTER - 15/30/90 - 6(VNIR,G,R,NIR,SWIR,TIR)
16 DEIMOS/UK-DMC2 - 22.0 - 3(R,G,NIR)
17 Landsat-7 ETM+ 15 30.0 1 7(RGB-NIR-MIR-TH)
18 Landsat-5 TM - 30.0 - 5 (RGB-NIR-MIR-TH)
19 Terra/Aqua- MODIS 250 – 1000 - 36
The wavelength width of the different frequencies recorded by the satellite sensors
Frequency Acronym wave length range
Region Sub Region From To
Ultraviolet UV ~0.01μm ~0.40μm
Visible VIS ~0.40μm ~0.75μm
Infrared Near Infrared NIR ~0.75μm ~1.3μm
Short Wave Infrared SWIR ~1.3μm ~3μm
Mid Wave Infrared MWIR ~3.0μm ~6.0μm
Thermal TIR ~6.0μm ~15.0μm
Far Infrared FIR ~15.0μm ~0.1cm
What is Temporal Resolution? 8
No. Sensor Name Revisit Time
1 GEO EYE-1 2 – 8
2 WORLDVIEW-1 2 – 6
3 WORLDVIEW-2 1 – 3
4 WORLDVIEW-3 1
5 IKONOS-2 2 – 5
6 CARTOSAT-2A 5
7 SPOT 6&7 1
8 CARTOSAT-1 5
9 FORMOSAT-2 1
10 Quickbird-2 2 – 6
11 SPOT-5 2 – 3
12 TopSat 2-2.5
13 SPOT 1 to 3 -
14 SPOT-4 2 – 3
15 Terra- ASTER 4 – 16
16 DEIMOS/UK-DMC2 2 – 3
17 Landsat-7 ETM+ 16
18 Landsat-5 TM 16
19 Terra/Aqua- MODIS 1
The shortest revisit time elapsed between observations of the same
point on earth by a satellite
What is Radiometric Resolution?9
No. Sensor Name Bit size
1 GEO EYE-1 (11 bits) reassigned to 16 or 8
2 WORLDVIEW-1 (11 bits) reassigned to 16 or 8
3 WORLDVIEW-2 (11 bits) reassigned to 16 or 8
4 WORLDVIEW-3 (11 bits pan and 14 bits SWIR)
5 IKONOS-2 (11 bits) reassigned to 16 or 8
6 CARTOSAT-2A (10 bits) reassigned to 16 or 8
7 SPOT 6&7 (12 bits) reassigned to 16 or 8
8 CARTOSAT-1 (10 bits) reassigned to 16 or 8
9 FORMOSAT-2 (8 bits) delivered as 8 bits
10 Quickbird-2 (11 bits) reassigned to 16 or 8
11 SPOT-5 (10 bits) reassigned to 16 or 8
12 TopSat (11 bits) reassigned to 16 or 8
13 SPOT 1 to 3 (11 bits) reassigned to 16 or 8
14 SPOT-4 (11 bits) reassigned to 16 or 8
15 Terra- ASTER For 15/30m - 8bits, 90m - 16 bits
16 DEIMOS/UK-DMC2 (10 bits) reassigned to 8
17 Landsat-7 ETM+ (11 bits) reassigned to 16 or 8
18 Landsat-5 TM (11 bits) reassigned to 16 or 8
19 Terra/Aqua- MODIS (12 bits) reassigned to 16 or 8
Number of digital levels used to express the data collected by the sensor
http://pages.csam.montclair.edu/~chopping/rs/CCRS/chapter2/chapter2_5_e.html
Off-Nadir Angle 10
No. Sensor Name Off Nadir Angle1 GEO EYE-1 +/- 36 max.2 WORLDVIEW-1 +/- 37 max.3 WORLDVIEW-2 +/- 32 max.4 WORLDVIEW-3 +/- 30 max.
5 IKONOS-2 +/- 36 max.
6 CARTOSAT-2A +/- 45 max.
7 SPOT 6&7 +/- 45 max.
8 CARTOSAT-1 +/- 45 max.
9 FORMOSAT-2 +/- 45 max.
10 Quickbird-2 +/- 37 max.
11 SPOT-5 +/- 31 max.
12 Top Sat +/- 45 max.
13 SPOT 1 to 3 +/- 31 max.
14 SPOT-4
15 Terra- ASTER
16 DEIMOS/UK-DMC2 +/- 12 max.
17 Landsat-7 ETM+
18 Landsat-5 TM
19 Terra/Aqua- MODIS
The angle that the satellite lens looks at the earth from
At-nadir : point the satellite is looking directly down at the ground
Off-nadir : how far the angle of the lens is tilted
http://marswiki.jrc.ec.europa.eu/wikicap/index.php/VHR_spaceborne_sensors,_suitable_for_LPIS_creation_and_update
San Francisco, 45 deg. off-nadir - an extreme example
Archived vs and Tasked Imagery 11
Archive imagery is from a library of data that has been collected and stored from
the launch date of the satelliteTasked imagery are new
acquisition planned for the future
Can weather or clouds affect the imagery? 12
Clouds affect optical imageries but radar imagery can capture through clouds
Check for the percentage of clouds in the scene through online catalogue before ordering the imagery
18/04/2011- TerraSAR -X30/04/2011- World view 01
13
Geodata
Formats
14
Data Format : Vector and Raster Data
Dhaka
Khulna
Rajshahi
Chittagong
Comilla
Vector Data
- Shapefile (.shp)
Raster Data
- TIFF
- JPEG
- HDF
- netCDF
Data Formats: Raster 15
No. Sensor Name Data Format1 GEO EYE-1 Geo TIFF, NITF-2.0/2.1
2 WORLDVIEW-1 Geo TIFF, NITF-2.0/2.1
3 WORLDVIEW-2 Geo TIFF, NITF-2.0/2.1
3 WORLDVIEW-3 Geo TIFF, NITF-2.0/2.1
4 IKONOS-2 Geo TIFF, NITF-2.0/2.1
5 CARTOSAT-2A LGSOWG, Geo TIFF, Fast Format
6 SPOT 6&7 DIMAP, Geo TIFF
7 CARTOSAT-1 LGSOWG, Geo TIFF, Fast Format
8 FORMOSAT-2 DIMAP, Geo TIFF
9 Quickbird-2 Geo TIFF, NITF-2.0/2.1
10 SPOT-5 DIMAP, Geo TIFF
11 TopSat JPEG, TIFF, GeoTIFF
12 SPOT 1 to 3 DIMAP, Geo TIFF
13 SPOT-4 DIMAP, Geo TIFF
14 Terra- ASTER HDF, Geo TIFF
15 DEIMOS/UK-DMC2 DIMAP, Geo TIFF
16 Landsat-7 ETM+ Fast Format, HDF,
17 Landsat-5 TM Fast Format, HDF
18 Terra/Aqua- MODIS HDF, GeoTIFF
Few of the commonly available formats:
• Geo Tagged Image File Format- Geo TIFF
• Joint Photographic Experts Group -JPEG2000
• Band Interleaved by Line- BIL
• Band Sequential – BSQ
• Hierarchical Data Format - HDF
• National Imagery Transmission Format – NITF
• Digital Image Map Format- DIMAP
• Multi resolution seamless image database –MrSID
• Landsat Ground Station Operators Working Group - LGSOWG
16
Data Sources
Where can we get data from?
Government Space Agencies
17
• National Aeronautics and Space Administration | NASA
• Russian Federal Space Agency | FKA
• European Space Agency | ESA
• Centre national d'études spatiales | CNES
• Japan Aerospace Exploration Agency | JAXA
• German Aerospace Center | DLR
• Indian Space Research Organization | ISRO
• China National Space Administration | CNSA
• Canadian Space Agency | CSA
• And many more … … …
Source: NASA
Where can we get data from?
Private/Commercial Space Agencies
18
• DigitalGlobe
• Worldview 1 and 2
• Quickbird
• Geoeye
• IKONOS
• OrbView-1
• GeoEye-1
• SPOT IMAGE
• DMC International Imaging Images Copyright © DigitalGlobe.
19
Purpose of Geodata
How do I choose among the different options?
Purpose of Data 20
• All geospatial projects must have a goal/purpose
• Who is your end user ?
• What specific information you want to convey?
• What questions will you be answering?
• What do you want to display/highlight on your map?
• i.e. Hazard extent, population distribution in a city, location of schools, etc
Which data do I need for my project? 21
• What is the temporal resolution that I need?
• What is the level of details I want to achieve?
• Does the data already exist or should I collectthem ?
• Which format will I be able to process the data in?
• What is the level of processing required to turn my data into valuable information?
• What is the total cost of the image(s)? Do I have the funding availability?
22
Data Download
Free Data Portals 23
Data is also available FREE of charge
• MODIS data products
• Copernicus Sentinels
• World Pop
• TRMM and GPM Rainfall Measurement
• Open Street Map
• LANDSAT and ASTER imagery can be obtained through USGS
• Digital Elevation Models (DEM) (SRTM/GDEM)
• OCHA datasets for humanitarian response
(COD/FOD)
Research about availability of free dataset before purchasing online
24
How to review, assess and approach data
Data Assessment
Content: Information the data displays
Complexity: Level of detail provided in the data
Consistency: Check the data for accuracy through out the whole data set
Completeness: How much of the area does the data set cover. Are there any gaps in the information?
Vector: Check the 4 C’s
MODIS Rapid Response – Satellite Image25
https://earthdata.nasa.gov/earth-observation-data/near-real-time/rapid-response/modis-subsets
DEMO: USGS Earth Explorer
26
http://earthexplorer.usgs.gov/
Copernicus : Sentinels
27https://scihub.copernicus.eu/
28DEMO: Digital Globe
https://browse.digitalglobe.com/
29
DEMO: Precipitation Data
http://giovanni.gsfc.nasa.gov/giovanni/
30
DEMO: Humanitarian Data Exchange
https://data.humdata.org/
ArcGIS Online – Vector , Raster, Data Service31
Can be accessed from ArcMap Add data menu
Openstreet Map – Vector Baseline
BBBike Extracts - OpenStreetMap
32
http://extract.bbbike.org/ extract.bbike.org
33
Gridded Population: WorldPop
http://www.worldpop.org.uk/data/get_data/
Rapid Response Products: UNOSAT
34
http://www.unitar.org/unosat/
UNITARInternational Environment HouseChemin des Anémones 11-13,CH-1219 Châtelaine, Geneva - SwitzerlandT +41 22 917 8400F +41 22 917 8047www.unitar.org
United Nations Institute for Training and ResearchInstitut des Nations Unies pour la Formation et la RechercheInstituto de las Naciones Unidas para Formación Profesional e InvestigacionesУчебньıй и научно-исследовательский институтОрганизации Объединенньıх Нацийمعھد الأمم المتحدة للتدریب والبحث
This presentation should not be copied or disseminated in any manner without the express permission of UNOSAT.
In partnership with Introduction to the Use of Geospatial Information Technology for Drought Risk Management
Phnom Penh, Cambodia14-17 November, 2017