Wednesday, January 17, 2018
ELEMENTS OF IMAGE INTERPRETATION AND ANALYSIS
Elements of Image Interpretation
• Image interpretation requires explicit recognition of eight elements of image interpretation that form the framework and understanding of an image
Ø Shape
Ø Size
Ø Tone
Ø Texture
Ø Shadow
Ø Site
Ø Association
Ø Pattern
Shape
Shape refers to the general form, structure, or outline of individual objects.
Shape can be a very distinctive clue for interpretation
Many natural and human-made features have unique shapes.
Often used are adjectives like linear, curvilinear, circular, elliptical, radial, square, rectangular, triangular, hexagonal, star, elongated, and amorphous.
• Shadow
• They are helpful in interpretation as it may provide an idea of the profile and relative height of a target or targets
• However, shadows can also reduce or eliminate interpretation in their area of influence, since targets within shadows are much less discernible from their surroundings
• Shadow is also useful for enhancing or identifying topography and landforms.
• Size
• Size of objects in an image is a function of scale. It is important to assess the size of a target relative to other objects in a scene, as well as the absolute size, to aid in the interpretation of that target.
• For example, to distinguish zones of land use, an area with a number of buildings in it, large buildings such as factories or warehouses would suggest commercial property, whereas small buildings would indicate residential use
• Tone/ Color
• Refers to the average brightness of an area or, in the case of color imagery, to the dominant color of the region
–Depends on the nature of the surface in the ankles of observation and illumination.
–Smooth surfaces behave like specular reflectors, they tend to reflect radiation in a single direction
• These features may appear bright or dark
–Rough surfaces behave as diffuse reflectors.
• Scatter radiation in all directions.
• Texture
• Texture refers to the arrangement and frequency of tonal variation in particular areas of an image.
• Rough textures would consist of a tone where the grey levels change abruptly in a small area. Whereas smooth textures would have very little tonal variation.
• Smooth textures are such as fields, water, or grasslands. Rough surfaces are such as a forest canopy, results in a rough textured appearance
• Pattern
• Refers to the spatial arrangement of visibly discernible objects in an image.
• Typically an orderly repetition of similar tones and textures will produce a distinctive and ultimately recognizable pattern.
• Orchards with evenly spaced trees and urban streets with regularly spaced houses are good examples of the pattern.
• Association
• This takes into account the relationship between other recognizable objects or features in proximity to the target of interest.
• The identification of features that one would expect to associate with other features may provide information to facilitate identification.
• For example, commercial properties may be associated with proximity to major transportation routes, whereas residential areas would be associated with schools, playgrounds, and sports fields.
• Site
• Refers to a feature's position with respect to topography and drainage.
– Some things occupy a distinctive topographic position because of their function
• Sewage treatment facilities at the lowest feasible topographic position.
• Power plants located adjacent to water for cooling
• Many image processing and analysis techniques have been developed to aid the interpretation of remote sensing images and to extract as much information as possible from the images.
• The choice of specific techniques or algorithms to use depends on the goals of each individual project
• Prior to data analysis, initial processing of the raw data is usually carried out to correct for any distortion due to the characteristics of the imaging system and imaging conditions
• These procedures include:
• Radiometric correction to correct for uneven sensor response over the whole image and
• Geometric correction to correct for geometric distortion due to Earth's rotation and other imaging conditions (such as oblique viewing)
Image processing techniques
• The techniques fall into three broad categories:
– Image Restoration and Rectification
– Image Enhancement
– Image Classification
• Image Restoration
• Most recorded images are subject to distortion due to noise which degrades the image.
• Two of the more common errors that occur in multi-spectral imagery are striping (or banding) and line dropouts
• Striping (or banding)
• Dropped Lines are errors that occur in the sensor response and/or data recording and transmission which loses a row of pixels in the image.
Image Enhancement
• One of the strengths of image processing is that it gives us the ability to enhance the view of an area by manipulating the pixel values, thus making it easier for visual interpretation.
• Techniques which we can use to enhance an image are such as Contrast Stretching and Spatial Filtering.
• Contrast Stretching
• Contrast enhancement involves changing the original values of image pixels so that more of the available range is used, this then increases the contrast between features and their backgrounds.
• Spatial Filtering
• Spatial filters are designed to highlight or suppress features in an image based on their spatial frequency.
• The spatial frequency is related to the textural characteristics of an image
• Rapid variations in brightness levels ('roughness') reflect a high spatial frequency; 'smooth' areas with little variation in brightness level or tone are characterized by a low spatial frequency
Image Classification
• In digital images processing, two methods are used to classify an image:
• Unsupervised Classifications and Supervised Classifications.
• Unsupervised Classifications
• This is a computerized method without direction from the analyst in which pixels with similar digital numbers are grouped together into spectral classes using statistical procedures such as nearest neighbor and cluster analysis
• The resulting image may then be interpreted by comparing the clusters produced with maps, air photos, and other materials related to the image site
• In this classification, the spectral features of some areas of known land cover types are extracted from the image by the analyst.
• These areas are known as the "training areas".
• Every pixel in the whole image is then classified as belonging to one of the classes depending on how close its spectral features are to the spectral features of the training areas.
• To generate colour images the three grey scale images need to be displayed in the three primary colours red, green and blue.
• A combination of different proportions of the three primary colours gives the full spectrum of colours.
• When images acquired in the red, green and blue parts of the electromagnetic spectrum are displayed in red, green and blue colour, respectively, the output composite image is called a true or natural colour image.
• On a true colour image, the colours of an object are similar to the colours the human eye perceives in real life – i.e., a green tree appears green, a blue lake appears blue, etc.
• Any image acquired in any part of the EM spectrum can be coded in any colour to generate a colour composite image.
• However, the colours in the output image will vary depending on the choice of the images and the choice of the colour in which they are displayed.
• As the colours of objects on the output image are different from what a human eye perceives, these images are called false colour composites.
Tuesday, January 9, 2018
GE 245- GROUP ASSIGNMENTS ON APPLICATIONS OF REMOTE SENSING (FOR CLASS PRESENTATIONS) JAN 2018
GE 245- GROUP ASSIGNMENTS ON APPLICATIONS OF REMOTE SENSING (FOR CLASS PRESENTATIONS) JAN 2018
1. Remote sensing offers a synoptic view of the spatial distribution and dynamics of hydrological phenomena, often unattainable by traditional ground surveys. With examples discuss this contention.(SOLIDARITY GROUP)
2. Discuss the role of remote sensing in monitoring different land-use changes(TUMAINIGROUP)
3. Explain how multitemporal analyses of remotely sensed data provide a unique perspective of how cities evolve.(TEACHERS GROUP)
4. Agriculture plays a dominant role in the economies of both developed and developing countries. Describe how remote sensing tools are used as mapping tools to classify crops, examine their health and viability, and monitor farming practices. (WE ARE IN THE SKY GROUP)
5. Both commercial and non-commercial forestry utilises a particularly diverse range of remote sensing applications. Explain this statement by giving clear examples. (WHITE ANGEL GROUP)
6. Remote sensing provides a means of quickly identifying and delineating various forest types, a task that is difficult and time-consuming using traditional ground surveys. How far is this statement true?(GLORIUS GROUPS)
7. State how remote sensing can be used to detect and monitor forest fires and re-growth following a fire. (GOLDEN GROUP)
8. Describe the applications of remote sensing in the following geological/geomorphologic activities:
(a) Mineral exploration (b) Geologic Unit Mapping (PLATO GROUP)
(c) Volcanism (d) Glacial/ice depletion (NYERERE 2A GROUP)
9. Explain the application of remote sensing in the ocean and coastal monitoring.(PATRIOTIC GROUP)
10. What are the utilities of remote sensing in mapping science?(NEW LIGHT GROUP)
11. Explain how remote sensing can be a tool for weather monitoring and forecast. (EDUCATION FIRST GROUP)
12. How can remote sensing imagery be used to estimate population size, distribution, and quality of life?(WISDOM GROUP)
13. Explain the application of remote sensing in hazard mitigation. (LIBERATION GROUP)
14.“One of the sensitive areas to be managed carefully in Tanzania is the wildlife sector”. With examples from the literature discuss this claim. (REVOLUTION GROUP)
15. How is remote sensing important in monitoring Land use and land cover changes of the environment? (UHURU GROUP)
16. Monitoring urban growth and change is one of the questions social scientists, urban planners and decision-makers deal with most frequently. Explain the usefulness of remote sensing tool in monitoring urban growth and change. (HOPE GROUP)
17. “Remote sensing is primarily used in the context of disease mapping”. Elaborate this contention (REPUBLICAN GROUP)
19. Explain the application of remote sensing in watershed management (PEACE & LOVE GROUP)
20. Illustrate the applications of remote sensing in Meteorological Sciences (HONEST GROUP)
21. Explain how a remote sensing tool can be used in water resources management (BRIGHT GROUP)
22. “Remote Sensing is a very important tool in coastal resource mapping”. Elaborate this statement. (RANGERS GROUP)
NB:
· It is advised that everyone should make his/her own copy of this sheet of questions for studying.
· Each presentation will last for ten minutes. It is advised that each group go digital by presenting their work in powerpoint to attract more scores
· Every member of a particular group should be present during presentation
· Which group should present on a particular day, remain in the hands of the course instructors i.e the instructors will decide promptly in class on which group to present
· Presentation will be conducted on Fridays starting from 19th January 2018
Wednesday, April 15, 2015
GE 352: PROTECTED AREAS MANAGEMENT (Lecture)
PROTECTED AREAS MANAGEMENT
Meaning
IUCN; an area of land or sea specifically dedicated
to the protection and maintenance of biological diversity, and of natural
and associated cultural resources managed through legal or other
effective means
Origin
Rio de Janeiro Earth Summit 1992 (United Nations
Convention on Biological Diversity )
That; Each
party must as far as possible:
1.
Establish a system of protected areas or
areas where special measures need to be taken to conserve biological diversity
2.
Develop where necessary guidelines for
the selection, establishment and management of protected areas
Protected areas meet the general purposes as
in the definition, but in practice the precise purpose for which
protected areas are managed differ from different categories
THERE ARE SIX (6) CATEGORIES/TYPES (IUCN CATEGORY);
1
(a)Strict nature reserve or (b) Wilderness area
2
National Park
3
Natural Monument
4
Habitat/Species Management Area
5
Protected landscape/seascape
6
Managed resource protected area
1. (a)STRICT NATURE RESERVE
Purpose; for science (The study of physical and
Natural world)
It is an area of land or sea possessing some
outstanding or representative ecosystems, geological or physiological features
or species available primarily for scientific
research or environmental
monitoring
Eg. Amani Nature Reserve Eastern Arc mountain (Uluguru, East Usanbara,Udzungwa)-
propositions are underway
(b) WILDERNESS AREA
An area managed mainly for wilderness protection
Unmodified or slightly modified land or sea
retaining its natural character and influence without permanent or significant
human habitation which is protected and managed so as to preserve its natural
condition.
Uninhabited area of land in its natural uncultivated
state, sometimes deliberately preserved. e.g. a forest or mountainous region,
dry area wetlands etc
2: NATIONAL PARKS
-Purpose; ecosystem protection and recreation
Eg. Serengeti, Mikumi, etc
- It is
a natural area of land or sea designed
*To protect ecological integrity of one or more
ecosystems for present and future generations.
*To exclude exploitation or occupation to the
purposes of designation/specification of the area.
*For spiritual scientific, educational, recreational
and visitor opportunities, all of which must be environmentally and culturally
compatible.
3. NATURAL MONUMENT S
Purpose; conservation of specific natural features
or historical, cultural, and aesthetic importance
Eg. Mbozi
meteorite, Amboni caves, Natural monument in lake Manyara , Bismark rocks –
Mwanza.
An area containing one or more specific natural or
cultural feature which is of outstanding or unique value because of its
inherent rarity, representative qualities,
or cultural significance.
4: HABITATS OR SPECIES MANAGEMENT AREA
Purpose; to manage the areas for conservation
through management intervention
(Endangered species protection/ management)
E.g. Game reserves – habitat, Ngorongoro
conservation area (NCA) – species – habitat
It is the area of land or sea subjected to active
intervention for management purposes so as to ensure maintenance of habitats to
meet the requirements of specific species.
5: PROTECTED
LANDSCAPE OR SEASCAPE
-Purpose; management of landscape and seascape for
conservation and recreation.
E.g. *Seascape in Tanzania; Rufiji – Mafia complex
*Landscape Longido Heart lands; slopes of mount
Kilimanjaro and Savannah area of Longido Contains mammal and birds (more than
400 species)
In this area, the Maasai people (pastoralists) have
lived here for over 400 years; they have co-existed with the wildlife in a
relative harmony.
Tarangire / Manyara Heart land
It is an area of land or sea where the interaction
of people and nature overtime has produced an area of distinct character with
significant ecological or cultural values and often with biological diversity.
6. MANAGED RESOURCES PROTECTED AREA
Purpose;
to protect a resource for sustainable use of ecosystem
E.g. many forest reserves, Kazimzumbwe protected
area, Mafia Island, Mnazi bay, Ngorongoro Crater etc
It is an area containing predominantly natural
systems managed to ensure long term protection and maintenance of biological
diversity while at the sometime providing sustainable flow of natural products
and services to meet community needs.
By
Chrisant, E
HOD Geography
St. Augustine University of
Tanzania- Mwanza
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