Human Footprint Flashcards
What is human footprint?
- A geographic extent of land under human use
- A measure of how much we are using the Earth’s natural resources
- A metric that allows us to calculate human pressure on Earth
no perfect definition
Indicators – How big is our footprint?
- It can be assessed by size of the population
- The amount of human settlements (ex. cities)
- The degree of resource extraction (ex. deforestation, oil/gas,
mining) - The number of products people consume
- The number of cars being driven
o And how much/often they are driven - Many more
Why Monitor the Human Footprint?
* The human footprint is a useful tool for:
* Assessing human impact on the world
* Environmental
* Economic
* Social
* So we can make decisions/planning on:
* Resource management
* Land-use planning
* Ex. Urban planning
* Conservation focuses
Human Footprint
- Hard to quantify and define
Earth observation remote sensing allows us to standardize
Measuring the human footprint is difficult because:
- There are multiple scales to consider
- Individual, family, city, country, global scales
- It is constantly changing
- Hard to find detailed data with global coverage
- Uncertain definition
- There is no clear and universally accepted definition
Historical Monitoring of the Human Footprint
- Often quantified with urbanization and population growth
- However, prior to satellites urbanization was often mapped with
aerial photography
Urban change from aerial photography
Aerial imagery provide the longest-available record of landscape change (~100 years)
- Early aerial photos are useful for comparative investigation with more recent satellite imagery
- Reveal the historical lay-of-the-land of the present-day cities or transformation rural- urban
Early aerial photography
- Aerial photo was the first form of remote sensing used
- During WWI (1914-1918) used for military reconnaissance
- After the war Canada with surplus of planes and camera equipment given by Britain
- Started to be used for civilian applications
- Surveillance – forest fire detection,
fisheries - Mapping – urban areas
Characteristics of early aerial images
- High spatial resolution (~1m)
- Panchromatic (Black and white)
- Vertical or oblique
- Individual photographs have
limited spatial coverage - Need to be mosaicked
- Spatial/temporal coverage depend on needs of original project
Measuring Human Footprint with Satellites
True and false colour composites allow us to track urbanization through time
Back to the 70s & 80s in the case of Landsat
Measuring Human Footprint with Satellites
But it can be hard to distinguish/classify urban areas with traditional imagery (true color)
because the urben colors are so variable ,
**Why is night lights data advantageous (compared to daytime satellite
imagery) when trying to map urban areas?
day time satelite imagery of urban areas can result in the area having a high variety of colors thus a wide variety of spectral signutures
night lights data standerlizes that, night lights look the exact same
and that makes it easier to see what is urban areas as urban areas contribute to human footprint
Night Lights Datasets
- The Operational Linescan System (OLS)
onboard the Defense Meteorological
Satellite Program (DMSP)
- Originally designed to detect clouds at night And aid in meteorological interpretation
- But also detected city lights, gas flares, and fires
- Operated from 1992 – 2013
- Produced the first dataset of night lights from space
- Measured **radiation **from 500 – 900nm
DMSP-OLS limitations:
- Coarse spatial resolution (~2.7 km)
- Low sensitivity
- Saturation on bright pixels (e.g. city
centers) - Limited low light detection capability
(ex. rural areas) - Limited spectral resolution
- No in-flight calibration
Night Lights Datasets
*** The Visible Infrared Imaging Radiometer Suite (VIIRS) **
onboard the joint NASA/NOAA Suomi National Polar-orbiting Partnership (SuomiNPP)
- Provides global daily measurements of night lights data since 2011
- Improvements include:
- Higher spatial resolution 375 – 750m
- Daily temporal resolution
- More complete global coverage
- Improved sensitivity
- Can measure very bright and minimally bright lights better
- More spectral resolution
- In flight calibration(can fix its calebration automatically depending of atemosphereric area)
