Spatial Data Science Final
Define remote sensing
"Science and art of obtaining information about an object, area or phenomenon through an analysis of data acquired by a device that is not in direct contact with the area, object or phenomenon under investigation."
What are the elements of remote sensing?
- Energy Source or Illumination (A) - Radiation and the Atmosphere (B) - Interaction with the Target (C) - Recording of Energy by the Sensor (D) - Transmission, Reception, and Processing (E) - Interpretation and Analysis (F) - Application (G)
Describe satellite images
- large area coverage - geometrically accurate - low spatial resolution - Limited flexibility on image acquisition
Describe aerial photographs
- small area coverage - Severe distortion - high spatial resolution - flexible on image acquisition
What are the UNs SDGs (17)?
1. No poverty 2. Zero hunger 3. Good health and well-being 4. Quality education 5. Gender equality 6. Clean water and sanitation 7. Affordable and clean energy 8. Decent work and economic growth 9. Industry, innovation, and infrastructure 10. Reduced inequalities 11. Sustainable cities and communities 12. Responsible consumption and production 13. Climate action 14. Life below water 15. Life on land 16. Peace, justice, and strong institutions 17. Partnerships for the goals
What are the two types of sensing systems?
1. Passive 2. Active
What are the 3 segments of GPS?
1. Space segment 2. Control segment 3. User segment
What is differential correction (GPS)?
1. Station set up over known position (Base). 2. Station set up at unknown point. 3. Collect data simultaneously. 4. Calculate new points from known Base Station and difference. Using two units to improve accuracy
What are the 2 major remote sensing platforms?
1. aerial photographs 2. satellite images
What are the 3 types of scale?
1. graphic 2. verbal 3. ratio
What are the four types of resolution that all remote sensing systems have?
1. spatial resolution 2. spectral resolution 3. temporal resolution 4. radiometric resolution
What are the 4 v's that are exemplary of Earth system data?
1. volume (data size) 2. velocity (speed of change) 3. variety (diverse data sources) 4. veracity (uncertainty of data)
What are common scales?
7.5 minute series (most detailed) 30x60 minute series (more area - less detailed) 1 x 2 degree series (large area - little detail)
What does small-scale mean?
A large denominator gives a small fraction resulting in a small scale (LESS DETAIL)map showing a larger area
What is map graphical scale?
A map element used to graphically represent the scale of a map. Graphical scales can be enlarged and reduced and still remain meaning Graphical scale may be culture bound (miles vs. kilometers) and is only accurate at the center of the map
What is a map ratio scale?
A ratio scale will almost always be found on maps. It is very accurate. 1:24,000 means that 1 cm = 24,000 cm, 1 m = 24,000 m
What is a map?
A representation of the world The traditional way of representing, storing, and visualizing geographic data Map is an abstraction of an area of the world
How do sensor systems work?
A sensor system records electromagnetic (EM) radiation detected as a combination of reflected solar radiation and emitted radiation by an object
What does a large-scale mean?
A small denominator gives a large fraction resulting in a large scale(MORE DETAIL) map showing a smaller area covers a smaller geographic area and has more details
What is map verbal scale?
A stated scale that says exactly how much distance is represented by a certain measurement (i.e. 1 cm = 8 km) It is the most useful scale for calculating distances
What accounts for inaccuracies for GPS?
Atmosphere (10 meters) Orbit Error (5 meters) Electronic "noise" (meters) Clock Error (meters) § Multipath Error (meters) Receiver Error (any size) Geometric Effects (Dilution of Precision) Operator Error (to 100s of meters)
How can maps be stored?
Brains Printed on paper Computers, the Web
What are the 4 links between climate and sustainability?
Climate Change: temperature change, precipitation change, extreme events, sea level rise climate process drivers: GHG concentration and emissions, aerosol concentration and emissions Impact and Vulnerability: ecosystems and water resources, food security, settlements and society, human health Socio-Economic Development: governance, health, literacy, technology, trade, equity, population, production/consumption, socio-cultural preferences
What did the IPCC 2022 report focus on?
Climate change: a threat to human wellbeing and health of the planet.
Advantages of Satellite Images
Covers large areas Cost effective Time efficient Multi-temporal Multi-sensor Multi-spectral Overcomes inaccessibility Faster extraction of GIS-ready data
What is the relationship between scale and spatial resolution?
Data are fine-scaled if they include more records of small objects or high spatial resolution Data are coarse-scaled if they include fewer records of larger objects or low spatial resolution
What can deep learning reveal about short-term crop yield?
Deep learning models allow for near real-time forecasting of crop yield throughout the year and can usually provide reliable predictions 2-3 months before the harvest
What is post-processed DGPS?
Differential Global Positioning System rover and base station data are transported to a computer and the differential corrections from the base station are applied to the rover data
How does remote sensing work?
Electromagnetic radiation (EMR) carries information between objects on earth surface and sensors
How are remote sensing and radiometric resolution related?
Every time an image is acquired by a sensor, its sensitivity to the magnitude of the electromagnetic energy determines the radiometric resolution
What softwares have contributed to the rise of geospatial big data?
GIS, RS, GPS
What kind of system is GPS and how does it work?
GPS is a ranging system 1. A GPS receiver ("the user") detects ranging signals from several satellites: Each transmission is time-tagged, Each transmission contains the satellite's position 2. The time-of-arrival is compared to time-of-transmission 3. The delta-T (i.e., time difference) is multiplied by the speed of light to obtain the range 4. Each range puts the user on a sphere about the satellite 5. The intersections of several spheres yields the user position
What is GPS?
Global Positioning System A system to calculate a position or coordinate on the Earth's surface A satellite-based global positioning system It uses range measurements based on radio signals Funded and controlled by U.S. the Department of Defense
What are the 4 grand challenges facing humanity and the society?
Human health food security energy security water security
How would the warmer and wetter climate affect terrestrial evapotranspiration (ET) across the global land surface?
In both emission scenarios, ET shows increase in most regions of the world. High emission scenario shows higher increase in ET than low emission scenario. Particularly, high emission scenario would result in large ET increase in tropics.
What will investing in NCS now do?
Investing in NCS now to protect biodiversity will make them more climate resilient and strengthen their ability to act as long-term carbon sinks
Landsat 8 spectral resolution
Landsat 8 has a total of 11 bands that cover less wavelengths and each band is wider in terms of wavelength.
What are some high spatial resolution land sensors?
Landsat TM and ETM (30 - 60 m) SPOT (10 - 20 m) IKONOS (4, 1 m) Quickbird (0.6 m)
MODIS spectral resolution
MODIS has better spectral resolution because it has 36 relatively narrow bands that cover wavelengths from 0.4um to 14um
Define map scale
Map scale is the ratio or relationship between a distance or area on a map and the corresponding distance or area on the ground
What is map scale?
Map scale refers to the ratio between map distance and ground distance 1:24,000 > 1:100,000 large scale map tends to show more details
What areas hold most potential for NCS?
Much potential for NCS is situated in the less developed and developing countries and in areas inhabited by indigenous peoples who often have limited land rights
How can spatial data be applied to COVID-19 research?
Multi-source data: remote sensing product, census data, climate data Combined with a Big Data processing platform--Google Earth Engine
How can spatial data be applied to the eutrophication problem?
N yield and movement form land to aquatic systems/oceans
What are examples of multispectral satellites?
NOAA-AVHRR (1100 m) GOES (700 m) MODIS (250, 500, 1000 m) Landsat TM and ETM (30 - 60 m) SPOT (10 - 20 m) IKONOS (4, 1 m) Quickbird (0.6 m)
What solutions are critical for the pathway to Paris?
Natural Climate Solutions
What are common map elements?
Neat line, border, title, figure, ground, inset, place-name, north arrow, credits, legend, scale
Disadvantages of Satellite Images
Needs ground verification Doesn't offer details Not the best tool for small areas Needs expert system to extract data
Technical Aspect of MODIS (orbit, time to cross equator, sensor systems, radiometric/temporal/spatial resolution, design life)
Orbit: 705 km Time to cross equator: 10:30 a.m. descending node (Terra) sun-synchronous, near-polar, circular Sensor Systems: Across Track Scanning (Wiskbroom) Radiometric resolution: 12 bits Temporal resolution: 2 days Spatial Resolution: 250 m (bands 1-2) 500 m (bands 3-7) 1000 m (bands 8-36) Design Life: 6 years
What is the relationship between scale and geographic events?
Projects, maps, and datasets that cover a large geographic extents are considered large-scale. Projects, maps, and datasets that cover a small geographic extents are considered small-scale.
What are the principles of map design?
Purpose Reality Available Data Map Scale Audience Conditions of use Technical Use
What are the 3 types of maps?
Reference maps: Comprehensive, authoritative, accurate, Basic features Thematic maps: Particular topics, Abstract or invisible concepts Dynamic maps: Interactive, changeable (themes and symbols)
Why is scale important?
Scale of data plays an important role, and frequently causes problems All spatial phenomena have scale dependent behavior/properties Be aware of: Data source scale, Mixing data from different source scales, Appropriateness of output scale_
What is radiometric resolution?
Sensor's sensitivity to the magnitude of the electromagnetic energy Sensor's ability to discriminate very slight differences in (reflected or emitted) energy
Define temporal coverage
Temporal coverage is the time period of sensor from starting to ending. ex. MODIS/Terra: 2/24/2000 through present Landsat 5: 1/3/1984 through present ICESat: 2/20/2003 to 10/11/2009
Define temporal resolution
Temporal resolution is the revisit period, and is the length of time for a satellite to complete one entire orbit cycle, i.e. start and back to the exact same area at the same viewing angle ex. Landsat needs 16 days, MODIS needs one day, NEXRAD needs 6 minutes for rain mode and 10 minutes for clear sky mode.
What is the relationship between radiometric resolution and energy detection?
The finer the radiometric resolution of a sensor, the more sensitive it is to detecting small differences in energy
What is the relationship between spectral resolution and wavelength?
The finer the spectral resolution, the narrower the wavelength range for a particular channel or band
What does scale refer to?
The term scale has been assigned different meanings by scientists, cartographers, and users ex. Detail, Extent, Map Scale all scale statements should be assumed unit-to-unit
What are symbol types and dimensions?
Three symbol types: point, line, area (polygon) Symbol dimensions: size, shape, color, and pattern (arrangement, orientation, texture - spacing)
What is needed to successfully include NCS in Sustainable Development Goals (SDGs)?
To successfully include NCS in Sustainable Development Goals (SDGs) and effectively implement policies and direct funding comprehensive metrics and monitoring, reporting and verification (MRV) are needed that include biodiversity, ecosystem services and local livelihoods, alongside carbon sequestration
What is atmospheric delay?
When electromagnetic waves pass through the atmosphere, the signal propagation is delayed due to the change of medium density
What is the WAAS Differential?
Wide Area Augmentation System WAAS enable units started in 2003 Maintained by the Federal Aviation Administration Fully operational in 1999 North America only Improves accuracy from about 10 meters to about 1.5 meters 25 ground reference stations that collect signals and then send correction info to satellites which gets sent to your receiver
What may happen with Earth System feedbacks and NCS?
With further warming, Earth System feedbacks may increasingly destabilize ecosystems and undermine the long-term mitigation potential of NCS
What is MODIS?
coarse spatial resolution land sensor since 2000 Moderate Resolution Imaging Sensor 36 spectral bands 1 km, 500m and 250 m resolutions 1 to 2 day repeat cycle
What is AVHRR?
coarse spatial resolution land sensor since the 1970s Advanced Very High Resolution Radiometer 5 spectral bands 1.1 km resolution 12 hour repeat cycle
How is real time DGPS different than post-processed DGPS?
corrections are transmitted to field in near real time via a radio link
What does radiometric resolution do?
defines the range of values that an individual pixel can have (Quantization levels are referred to as Digital Numbers)
What is the key challenge for big data and process understanding for data-driven earth system science?
extract interpretable information and knowledge from this big data, possibly almost in real time and integrating between disciplines
What are important considerations for Natural Climate Solutions (NCS)?
must not replace or delay decarbonization efforts in other sectors
What are some potential applications of SDS?
public health water security, quantity, quality food security climate SDGs
What is differential positioning (GPS)?
simultaneous GPS measurements at field roving (unknown) and base (known) sites
Describe passive sensing systems
source of energy is either the Sun or Earth/atmosphere Sun: wavelengths: 0.4-5 µm Earth or its atmosphere: wavelengths: 3 µm -30 cm examples: Landsat, ASTER, Quickbard, Ikonos
Describe active sensing systems
source of energy is part of the remote sensor system Radar: wavelengths: mm-m Lidar: wavelengths (UV, Visible, and near infrared) examples: LIDAR, RADAR
What does scale/scaling look like?
spatial scale, temporal scale, up scaling, down scaling
What is the language of maps?
symbolization
Define spectral resolution
the ability of a sensor to define fine wavelength intervals