Introduction to Visual Image Interpretation, Chapter 4, Remote Sensing and Image Interpretation

1
Introduction to Visual Image Interpretation,
Chapter 4, Remote Sensing and Image
Interpretation
(Mercury Topography--Smithsonian)
2
Table of Contents

• Land Use
• Geologic Mapping
• Sedimentary Rocks
• Fractures and Faults
• Landform Identification and Evaluation
• Vegetation Indices
• Agriculture Applications
• Forestry Applications
• Range-land Applications
• Fluvial Erosion Deposition
• Water Resource Applications
• Environmental Assessment
• Flood Damage Estimation

3
Land Use/Land Cover Mapping

• Knowledge of land use and land cover important
  for planning and management activities.
• Land cover maps being developed from local to
  national to global scales.
• Panchromatic, medium-scale aerial photographs to
  map land use has been the acceptable way since
  1940s.
• More recently, small-scale aerial photographs and
  satellite images have been used for land use/land
  cover mapping.
• Land cover terminology relates to the type of
  feature present on Earths surface.
• Corn fields, lakes, maple trees, etc
• Land use relates to human activity.
• E.g., urban use, residential use, or
  single-family housing.
• Knowledge of both land use and land cover can be
  important.
• USGS devised land use and land cover
  classification system for use with remote sensor
  data in mid-1970s.

4
USGS Land Use / Land Cover Example

• Classification System listed on page 210 (Level 1
  and Level 2).
• 21 - Cropland and pasture
• 43 - Mixed forest land
• 61 - forested wetlands

(USGS)
5
High-Resolution Land Use and Land Cover mapping

• Left side - 1996
• Right side 2050 (predicted).

Albuquerque, NM
6
Geologic and Soil Mapping

• Earth has a highly complex and variable surface.
• Topographic relief and material composition
  follow the geology underlie each part of the
  surface.
• Type of rock, fractures, erosion, depositional
  features, etc, bear imprint of processes that
  produced them.
• Persons seeking to understand and explain Earth
  materials must be able to recognize surface
  expressions of various materials and structures.
• Visual image interpretation and geologic and soil
  mapping allow materials and structures to be
  identified and evaluated.
• Geologic and soil mapping will always require a
  considerable amount of surface field exploration.
• However, mapping process can be greatly
  facilitated through the use of image
  interpretation.

7
Geologic Mapping

• First aerial photographs for geologic mapping
  purposes taken in 1913 (Bengasi, Libya).
• Earliest uses of air photos were for geologic
  data base map compilation -- especially for
  petroleum exploration.
• Some interpretive uses of aerial photographs date
  back to the 1920s.
• Widespread use of air photos for geologic mapping
  and evaluation began in the 1940s.
• Geologic mapping involves the identification of
  landforms, rock types, and rock structures
  (folds, faults, and fractures).
• Much information about potential areas for
  mineral exploration can be provided by
  interpretation of surface features on aerial
  photographs and satellite images.

8
Geologic Applications

• Remote sensing useful for
• Mapping rock units (stratigraphy).
• Studying the expression and modes of the origins
  of landforms (geomorphology).
• Determining the structural arrangements of
  disturbed strata, such as folds and faults
  (structural geology).
• Evaluating dynamic changes from natural events,
  e.g., floods, volcanic eruptions, earthquakes
  (hazards).
• Seeking surface clues, such as alteration and
  other signs of mineralization, to subsurface
  deposits of ore minerals, oil and gas, and
  groundwater.

9
Sedimentary Rocks

• There are three general types of rock
• Sedimentary rocks most common and extend over 75
  of lands surface.
• Igneous rocks extend over 20 of lands surface.
• Metamorphic rocks extend over about 5.
• Sandstone, shale, and limestone are principal
  sedimentary rocks that are considered.
• Sedimentary rocks formed by consolidation of
  layers of sediments that have settled out of
  water or air.
• Clastic sediments are converted into coherent
  rock masses by lithification, a process which
  involves cementation and compaction by weight of
  overlying sediments.
• Nature of constituent particles and way in which
  they are bonded determine texture, permeability,
  and strength strength of the rocks.

10
Sedimentary Rocks (Continued)

• Sedimentary rocks containing primarily sand-sized
  particles are called sandstone.
• Those containing primarily silt-sized particles
  are called siltstone.
• Those containing primarily clay-sized particles
  are called shale.
• Limestone has high calcium carbonate content and
  is formed from chemical or biochemical action.
• Chemical precipitation of mostly calcium
  carbonate (CaCO3) from water.
• Biochemical processes acting on shells, shell
  fragments, and plant materials.
• Clastic deposition of shell material as marine or
  lacustrine environment.
• Principal sedimentary rock characteristics that
  affect appearance on aerial and space images are
  bedding, jointing, and resistance to erosion,
  i.e., resistant cliff forming strata.

11
Sedimentary Rocks (Continued)

• Sedimentary rocks are mostly stratified or
  layered.
• Individual layers called beds.
• Top and bottom of each bed have more or less
  distinct surfaces called bedding planes that
  terminate one bed and begin another, i.e.,
  unconformities.
• Individual beds have somewhat different
  characteristics.
• Thickness varies from few millimeters to hundreds
  of meters
• Usually start off nearly horizontal but may tilt
  due to movements of earths crust, i.e., tectonic
  activity.
• Joints are cracks through solid bodies of rocks
  that that have little or no movement parallel to
  joint surfaces.
• Primarily perpendicular to bedding planes
• May intersect other joint planes
• Several systematic joints constitute joint set,
  and two or more sets in a recognized area form a
  joint system
• Streams often follow joint lines, moving from one
  to another.

12
Sedimentary Rocks (Continued)

• Resistance to erosion depends on rock strength,
  permeability, and solubility.
• Rock strength a function of bonding agent
• Thick beds of sandstone bonded by quartz
  (ortho-quartzite) are very strong and may be used
  as building material.
• Thin beds of shale are very weak.
• Permeability refers to ability of rock to
  transmit water and depends on pore spaces between
  sediment particles.
• Sandstone generally very permeable can be an
  aquifer.
• Shale is usually very impermeable, can be an
  aquaclude.
• Limestones are soluble in water over thousands of
  years, especially if carbonic acid present, e.g.,
  karst topography.

13
Sedimentary Rocks (Continued)

• Sandstone
• Bedding often prominent on images, especially
  when occurring over softer, more easily eroded
  formations such as shale.
• Jointing is prominent, with joint system
  consisting of two or three dominant directions.
• Resistance to erosion varies depending on
  strength of cementing agent.
• Cemented with iron compounds and silica typically
  strong, e.g., ironstone concretions.
• Cemented with carbonates weaker.
• Very permeable, with rainfall percolating
  downward through rock rather than becoming
  erosion-producing surface runoff.
• Percolating water can dissolve carbonate
  cementing agent.

14
Fractures and Faults

• A fracture (or joint) is a crack or break in the
  rock in which either side springs apart by a
  small distance.
• Seen from a distance as linear mark in which tone
  is same on each side.
• A fault is a break in which the rock on one side
  slides or slips against the rock on the other
  side so that each is displaced by some distance.
• Sharp discontinuity in tonal pattern is a
  distinct possibility.

(rst)
15
Morro Bay Imagery
(rst)
h-Morro Rock
16
Histogram from Morro Bay Imagery

• Big return at 12 due to ocean
• Returns around 28 from land

(Remote Sensing Tutorial)
17
Finding Oil

• Case study by Eason Oil and Earth Satellite Corps
• Landsat imagery examined in areas that have
  established petroleum reserves.
• Telltale surface indications
• Standard-processed and computer-enhanced data.
• Areas selected in which the surface does not give
  clear indication of subsurface conditions.
• If imagery identified hydrocarbons under
  difficult conditions, Landsat would increase in
  stature as an oil/gas discriminator.
• Andarko Basin of south-central Oklahoma selected.
• Basin, or down-sag, in crust allowed sedimentary
  rock to accumulate.
• Oil and gas present in structural and
  stratigraphic traps.

18
Finding Oil Continued
(rst)

• Surface expressions in basin meager.
• Investigators focused on undiscovered fractures
  and subtle chemical alterations.
• Results inconclusive and discouraging.

19
Elements of Image Interpretation for Landform
Identification and Evaluation

• Systematic observation and evaluation of key
  elements studied stereoscopically
• Topography
• Drainage pattern and texture
• Erosion
• Image Tone
• Vegetation
• Land use

20
Topography

• Each landform and bedrock type has own
  topographic form
• Typical size and shape
• Change at boundary between two different
  landforms
• Vertical photographs with normal 60 overlap
  appear exaggerated in height by three to four
  times for most individuals.
• Slopes appear steeper than they are
• Specific amount of vertical exaggeration observed
  in stereopair is a function of geometric
  conditions under which photographs are viewed and
  taken.

21
Stereo to Topography Methodology from Smithsonian
(Lunar Crater Topography)
22
Vegetation and Land Use

• Differences in natural or cultivated vegetation
  often indicate differences in terrain conditions,
  some examples
• Orchards and vineyards normally located on
  well-drained soils.
• Truck farming takes place on highly organic soil
  with perhaps large peat deposits.
• In other cases, vegetation and land use can
  obscure differences in terrain conditions.

23
Soil Mapping

• Employed heavily in comprehensive land use
  planning.
• Must be premised on thorough inventory of natural
  resource base.
• Detailed soil surveys are the product of
  intensive study of soil resources by trained
  scientists.
• Air photo interpretation has been heavily coupled
  with extensive field work.
• Soil scientists traverse landscape on foot,
  identify soils, and delineate soil
  boundaries.
• Relationships of soils to vegetation, geologic
  parent material, landform, and landscape
  position are evaluated.
• Air photo interpretation has been used since
  early 1930s to facilitate the soil mapping
  process.
• USDA has been preparing soil survey maps since
  about 1900.
• Most soil surveys since 1957 have contained soil
  maps on photomosaic base at a scale of 124000,
  120000, or 115840.

24
Agriculture Applications and Crop Management
Information

• Pre-planting variations studied in surface
  moisture, texture, and organic content.
• Plowing / Planting progress determined,
  drainage, runoff, and erosion.
• Emergence time delayed emergence detected, such
  as low plant density, insect, disease, or weather
  problems.
• Mid-growing season observed damage due to
  adverse moisture, misapplication of chemicals,
  insects, diseases, eroded top soil.
• Pre-harvest stand condition checked, acreage to
  be harvested, significant weed invasion.
• Post-harvest area determined to be harvested,
  weed and volunteer re-growth, erosion, and soil
  moisture problems.

25
Vegetation Indices

• Spectral bands can be combined to accentuate
  vegetated areas.
• Ratio Vegetation Index (RVI) is ratio of sensed
  radiation bands.
• RVI NIR / Red
• Vegetation has high NIR (Near Infrared) return
  and low red return.

(Virtual Science Centre)
26
Normalized Difference Vegetation Index (NDVI)

• NDVI (NIR - Red) / (NIR Red)
• NDVI band combined with other bands to form color
  composite.

( Virtual Science Centre)
27
Vegetation Applications

• Many sensors operate in green, red, and near IR
  (NIR) regions.
• Vegetation radiation absorption and reflectance
  discriminated.
• Absorption centered at 0.65 ?m (visible red) by
  chlorophyll pigment.
• This removes red and similarly blue from white
  light, giving green color of leaves.
• Strong reflectance between 0.7 and 1.0 ?m, NIR
  band.
• Tonal signatures on multispectral images
  distinct.
• Darker tones in blue
• Darker tones especially in red
• Somewhat lighter in green
• Notably lighter in near IR.

28
Vegetation Applications Continued
(rst)
29
Landsat Vegetation Application
(rst)
30
Principles of Landform Identification and
Evaluation

• Various terrain characteristics important to soil
  scientists, geologists, geographers, civil
  engineers, urban and regional planners, landscape
  architects, real estate developers, and others.
• Numerous terrain characteristics can be estimated
  by means of visual image interpretation, such as
  
• Bedrock type
• Landform
• Soil texture
• Site drainage conditions
• Susceptibility to flooding
• Depth of unconsolidated materials over bedrock

31
Forestry Applications

• Growing challenges exist with management of
  forests for wood, forage, water, wildlife, and
  recreation.
• Special concerns with timber management,
  maintenance, and improvement of existing stands.
• These cover nearly one-third of worlds land
  area.
• distributed unevenly with widely varying value.
• Visual image interpretation used to monitor many
  of worlds forest conditions.
• Trees identified on aerial and satellite images
  through process of elimination.
• Species eliminated which are impossible or
  improbable because of location, physiography, or
  climate.
• Groups of species identified in area.
• Identify individual tree species using basic
  image interpretation principles, such as
• Shape, size, pattern, shadow, tone, texture.

32
Vegetation and Deforestation

• AVHRR Index
• Europe probably most vegetated.
• South America next in vegetation.
• Australia least vegetated.

33
Vegetation and Deforestation

• Farmlands/open area in black.
• 200,000 out of 1.9 million square miles cleared.
• Public outcry slowing removal.

• Brazilian Amazon Deforestation
• Rain forests in blue/purple.
• Woodlands in green/yellow.

34
Range-land Applications

• Range-land defined as predominantly grasses,
  grass-like plants, or shrubs.
• Animal grazing important influence in
  pre-civilization state
• Potential land use as agriculture, recreation, or
  housing
• Range-land management utilizes science and
  experience for protection, improvement, and
  continued welfare of basic range-land resources.
• Soils
• Vegetation
• Endangered plants and animals
• Wilderness, water, and historical sites
• Emphasis placed on the following (table 4.14,
  page 247).
• Suitability of vegetation for multiple uses
• Design and implementation of vegetation
  improvements
• Implications of social and economic effects of
  alternate land use
• Control of range pests and undesirable vegetation
• Reclamation of soil and vegetation on disturbed
  areas.

35
Drainage Pattern and Texture

• Six common drainage patterns are illustrated in
  figure 4.36, page 287
• Dendritic formed by main stream with tributaries
  branching and rebranching
  freely.
• Rectangular dendritic pattern modified by
  structural bedrock such
  that tributaries meet at right angles. Typical of
  massive sandstone formations with well-developed
  joint system.
• Trellis drainage pattern consists of streams
  having one dominant direction, with subsidiaries
  at right angles. Occurs in areas of folded
  sedimentary rocks.
• Radial drainage pattern is formed by streams
  that radiate outward from a central area. Typical
  of volcanoes and domes.
• Centripetal reverse of radial drainage pattern
  in that drainage is directed a central point.
  Occurs in areas of limestone sinkholes, glacial
  kettle holes, volcanic craters, and other
  depressions.
• Deranged disordered pattern of of aimlessly
  directed short streams, ponds, and wetland areas
  of ablation glacial till areas.

36
Erosion

• Gullies are small drainage features that can be
  as small as a meter wide and a hundred meters
  long.
• Result from erosion of unconsolidated material
  from runoff
• Develop where rainfall cannot adequately
  percolate into ground but collects and flows
  across the surface in small rivulets
• Enlarge and take on shape characteristic of the
  material in which they are formed
• Short gullies with V-shaped cross sections tend
  to develop in sand and gravel (figs 4.38 and
  4.39, pages 288 and 289).
• Gullies with U-shaped cross sections tend to
  develop in silty soils (figs 4.38 and 4.39).
• Long gullies with gently rounded cross sections
  tend to develop in silty clay and clay soils
  (figs 4.38 and 4.39).

37
Water Resource Applications

• Water is one of our most critical resources uses
  are
• Irrigation
• Power generation
• Drinking
• Manufacturing
• Recreation
• Most sunlight absorbed within two meters of
  waters surface.
• Absorption highly dependent on wavelength.
• Near IR absorbed in few tenths of a meter of
  water, resulting in very dark tones.
• Absorption in visible portion dependent on
  characteristics of water body.
• Best wavelengths for clear, calm water
  penetration between 0.48 and 0.60 ?m (up to 20 m
  penetration).
• Sand bottoms appear blue-green using normal color
  film
• Color IR film clearer because blue filtered out
  and essentially no near IR (two-layer film).

38
USGS Water Use Program

• Analyze source, use, and disposition of water
  resources
• Reply to water-use information requests
• Document trends in water-use
• Cooperate with agencies on special projects
• Develop water-use data bases
• Publish water-use reports

39
Water Pollution Detection

• All natural water has some impurities.
• Considered polluted when presence of impurities
  sufficient to limit its domestic and/or
  industrial use.
• Not all pollutants the result of human activity.
• Minerals leached from soil
• Decaying vegetation
• Appropriate to consider two types of pollution
  sources.
• Point Highly localized, such as industrial
  out-falls
• Non-point Fertilizer and sediment run-off

40
Water Pollution Detection Continued

• Each of the following--when present in excessive
  amounts--can result in water pollution
• Organic wastes from domestic and industrial
  sources
• Infectious agents from domestic and industrial
  wastes
• Plant nutrients that cause nuisance growths
• Synthetic-organic chemicals such as detergents
• Inorganic chemical and mineral sources from
  mining / manufacturing
• Radioactive pollution and temperature increases.

41
Water Quality

• USGS operates two national stream water quality
  networks.
• Hydraulic Benchmark Network (HBN).
• National Stream Quality Accounting Network
  (NASQAN).
• Streams in watershed monitored to provide
  descriptions of stream water quality conditions.
• Understand effects of natural environment and
  human activities on water quality.

(USGS)
63 physical, chemical, and biological properties
monitored during 60,000 stream visits
42
USGS Hydrologlic Units Map

• U.S. divided into successively
• smaller hydrologic units.
• 21 major geographic areas
• Drainage area of major river
• Combined drainage areas of series of rivers
• 222 subregions
• Area drained by river system
• Reach of a river and tributaries.
• Closed basins
• Group of streams forming coastal drainage areas.
• 352 hydrologic accounting units
• Cataloging unit

(USGS)
43
Environmental Assessment

• Many human activities produce potentially adverse
  environmental effects, such as
• Highways, railroads, pipelines
• Airports
• Industrial sites
• Power plants and transmission lines
• National Environmental Policy Act (NEPA)
  established as national policy the creation and
  maintenance of conditions that encourage harmony
  between people and their environment.
• Environmental impact statements prepared for
  federal action having significant impact on
  environment.
• Remote sensing and image interpretation can be
  used to assist in all of the related areas
• Emergency response planning
• Landfill monitoring
• Permitting and enforcement
• Natural Disaster mitigation.

44
USGS Tracking Environmental Change

• Lake Chad on edge of Sahara
• Desert.
• Borders four countries in West Africa.
• Was once the sixth-largest lake in the world, but
  drought has shrunk it to one-tenth its former
  size.
• Flat and shallow, so small changes in depth mean
  huge change in area
• Was once highly productive and supported
  diversity of wildlife.

Landsat 1 MSS bands 4, 2, 1 (1973)
(USGS)
45
Wetland Mapping
46
Flood Damage Estimation
July 1992

• Scientific Assessment and Strategy Team (SAST)
  established to provide scientific advice and
  assistance regarding flood recovery in upper
  Mississippi River Basin.
• Natural flood plains
• Levies, dams, and dikes

July 1993
(USGS)
47
Image Interpretation Process Wrapup

• Through analysis, an image interpreter can
  identify different terrain conditions and
  determine the boundaries between them.
• Topography
• Drainage pattern and texture
• Erosion
• Image Tone
• Vegetation
• Land use
• Above elements considered individually and in
  combinations to estimate terrain conditions.
• Image interpretation is readily used in examining
  bedrock types
• Geologic origin and formation
• Soil and/or bedrock characteristics
• Implications for land use planning
• Image identification.

48
(Photogrammetry)
49
(Photogrammetry)
50
(Photogrammetry)
51
Supplemental References

• NASA Goddard Remote Sensing Tutorial
  http//rst.gsfc.nasa.gov/intro/Part2-12.htm
• National Oceanic and Atmospheric Administration
  (NOAA)http//www.noaa.gov/satellites
• Smithsonian Educational Datahttp//www.nasm.edu/c
  eps/research/cook/topography.htm
• Geomatics Horizonshttp//www.sli.unimelb.edu.au/H
  orizons/tnotes.html
• U.S. Geological Survey (USGS)http//www.usgs.gov/
  wrd002.html
• Photogrammetryhttp//www.sli.unimelb.edu.au/nicol
  e/lectures/lecintro.html
• Principles of Photogrammetry, R. Lathrop with
  Material from Avery and Berlin, 5th
  Editionhttp//deathstar.rutgers.edu/courses/airph
  oto/airphoto7/sld001.htm