Planning techniques geo informatics

Planning Techniques
Geo informatics
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Front Desk Architects and Planners Forum
http://www.frontdesk.co.in/forum

Remote sensing
Remote sensing (RS) is the art and science of making measurements of the
earth using sensors on airplanes or satellites. These sensors collect data in the
form of images and provide specialized capabilities for manipulating,
analyzing, and visualizing those images.
Active RS, systems which provide
their own source of energy to
illuminate the objects they observe.
Passive RS, systems which detect
natural energy (radiation) that is
emitted or reflected by the object
or scene being observed.
Global Positioning System (GPS) and Global Navigation Satellite Systems (GNSS)
Geographic Information Systems (GIS).

Remote sensing platforms
Remote sensing platforms can be defined as the structures or vehicles on
which remote sensing instruments (sensors) are mounted.
Types of platforms
1. Ground-borne platforms: Ground borne platforms are used to record detailed
information about the surface which is compared with information collected from
aircraft or satellite sensors i.e. for ground observation. Ground observation
includes both the laboratory and field study, used for both in designing sensors
and identification and characterization of land features
2. Air-borne platforms: Airborne platforms are used to collect very detailed
images and facilitate the collection of data over virtually any portion of the Earth's
surface at any time. Airborne platforms were the sole non-ground-based
platforms for early remote sensing work.
3. Space-borne platforms: In space-borne remote sensing, sensors are mounted
on-board a spacecraft (space shuttle or satellite) orbiting the earth. Space-borne
or satellite platform are onetime cost effected but relatively lower cost per unit
area of coverage, can acquire imagery of entire earth without taking permission.
Space borne imaging ranges from altitude 250 km to 36000 km.

Ground-borne platforms
Total Station or TST (total
station theodolite) : is an
electronic/optical instrument
integrated with an electronic
distance measurement (EDM)
used for surveying and
recorded data are then
downloaded into a CAD
program.
Differential GPS or DGPS survey
Digital Survey : Survey using Digital instrument like :

Air-borne platforms
Aerial Photography : When the ground resolution becomes less than 1 meter
than the digital cameras are very essential to perform remote sensing. Digital
Aerial Cameras are cameras that are designed to be used on flying survey
platforms. They are widely used for mapping projects in combination with
photogrammetric or LIDAR technology.
Photogrammetry comprises all techniques concerned with making
measurements of real-world objects and terrain features from images. These
may be aerial as well as terrestrial images, and they may be taken by film
cameras, digital cameras or electronic scanners on tripods, airborne or
spaceborne platforms.
LIDAR, Light Detection and Ranging, is a remote sensing method that uses light
in the form of a pulsed laser to measure ranges (variable distances) to the Earth.

Space-borne platforms
The path followed by a satellite is referred to as its orbit.
Type of orbit are: Polar orbit or sun synchronous orbit , Geostationary orbits
and geosynchronous orbit
Polar orbit
Geostationary orbits
Geosynchronous orbithttp://www.frontdesk.co.in/forum

Swath
India has also made lot of contribution in case of remote sensing specially in passive
remote sensing through IRS series then Resourcesat series then IRS p series, Cartosat series
etc.
As a satellite revolves around the Earth, the sensor "sees" a certain portion of the
Earth's surface. The area imaged on the surface, is referred to as the swath.
Imaging swaths for spaceborne sensors generally vary between tens and
hundreds of kilometres wide.

Sensors
Types of sensors used
in remote sensing.
Passive sensors detect
the reflected or
emitted electro-
magnetic radiation
from natural sources
Active sensors detect
reflected responses
from objects which
are irradiated from
artificially generated
energy sources, such
as radar.

Sensors
Each is divided further in to non-scanning and scanning systems.
A sensor classified as a combination of passive, non-scanning and non-imaging
method is a type of profile recorder, for example a microwave radiometer. A sensor
classified as passive, non-scanning and imaging method, is a camera, such as an aerial
survey camera or a space camera, for example on board the Russian COSMOS satellite.
Spatial resolution of the sensor and refers to the size
of the smallest possible feature that can be detected.
Spatial resolution of passive sensors depends
primarily on their Instantaneous Field of View (IFOV).
The IFOV is the angular cone of visibility of the
sensor (A) and determines the area on the Earth's
surface which is "seen" from a given altitude at one
particular moment in time (B). The size of the area
viewed is determined by multiplying the IFOV by the
distance from the ground to the sensor (C). This area
on the ground is called the resolution cell and
determines a sensor's maximum spatial resolution.http://www.frontdesk.co.in/forum

Remote sensing
(A) Energy Source
(B) Radiation and the Atmosphere
(C) Interaction with the Target
(D) Recording of Energy by the Sensor
(E) Transmission, Reception, and Processing
(F) Interpretation and Analysis
(G) Application
Remote sensing of reflected radiation Remote sensing of emitted radiation
By recording emitted or reflected radiation and applying knowledge of its behaviour as it passes
through the Earth’s atmosphere and interacts with objects, remote sensing analysts develop
knowledge of the character of features such as vegetation, structures, soils, rock, or water bodies
on the Earth’s surface.
VariousStepsin
Remotesensing

Electromagnetic (EM) Spectrum
Principal Divisions of Electromagnetic (EM) Spectrum
The optical spectrum, from 0.30 to 15 μm, defines those wavelengths that
can be reflected and refracted with lenses and mirrors.
The reflective spectrum extends from about 0.38 to 3.0 μm; it defines that
portion of the solar spectrum used directly for remote sensing.

Spectral signature
Everything in nature has its own unique distribution of reflected, emitted and absorbed
radiation.
These spectral characteristics can – if ingeniously exploited - be used to distinguish one
thing from another or to obtain information about shape, size, and other physical and
chemical properties.
A set of observations or measurements that constitutes a spectral response pattern is
called the spectral signature of an object.

Multi-Return Concept
LIDAR, which stands for Light
Detection and Ranging, is a remote
sensing method that uses light in
the form of a pulsed laser to
measure ranges (variable distances)
to the Earth.
LiDAR returns are discrete
observations recorded when a laser
pulse is intercepted and reflected by
targets. Multiple returns derive
from one laser pulse intercepting
multiple targets (e.g. a top of a tree,
its branches, and the ground).
Taken from : Fernandez-Diaz, J. C. (2011). Lifting the Canopy Veil - Airborne LiDAR for Archeology of Forested Areas.http://www.frontdesk.co.in/forum

Raster Data Processing and Analysis
Raster Types: Discrete vs Continuous
Raster data is made up of pixels (also referred to as grid cells). They are usually
regularly-spaced and square but they don’t have to be. Rasters often look pixelated
because each pixel has its own value or class. For example:
Each pixel value in a satellite image has a red, green and blue value. Alternatively, each
value in an elevation map represents a specific height. It could represent anything from
rainfall to land cover.
Raster models are useful for storing data that varies continuously. For example,
elevation surfaces, temperature and lead contamination.
DISCRETE RASTERS have distinct values
Discrete rasters have distinct themes or categories.
For example, one grid cell represents a land cover
class or a soil type.
In a discrete raster land cover/use map, you can
distinguish each thematic class. Each class can be
discretely defined where it begins and ends. In
other words, each land cover cell is definable and
it fills the entire area of the cell.http://www.frontdesk.co.in/forum

Raster Data Processing and Analysis
CONTINUOUS RASTERS have gradual change
Continuous rasters (non-discrete) are grid cells
with gradual changing data such as elevation,
temperature or an aerial photograph.
A continuous raster surface can be derived from a fixed registration point. For example,
digital elevation models use sea level as a registration point. Each cell represents a value
above or below sea level. As another example, aspect cell values have fixed directions
such as north, east, south or west.
Raster data are managed and analyzed in special-purpose software or environments, such
as ENVI or ERDAS Imagine for remote-sensing data, ArcGIS, GRASS or IDRISI for general-
purpose GIS-based data, or GrADS, IDL or NCL, for climate data, or with programs written
in Fortran or C (or more recently, Python). Typically, a user would do much of the basic
data processing in the specialized environment or programming language, then export
the data to R or another statistical package for data analysis and visualization, then move
the data back into the specialized software for further processing.

Resolutions of Raster Data
1. Spatial (what area and how detailed) Spatial Resolution describes how much
detail in a photographic image is visible to the human eye. The ability to
"resolve," or separate, small details is one way of describing what we call spatial
resolution.
2. Spectral (what colors – bands) Spectral responses from ground targets
are recorded in separate spectral bands by sensors. Number of spectral bands
(Red, Green, Blue, Near Infra Red, Mid-Infra Red, thermal, etc.) Panchromatic –
1 band (B&W) , Color – 3 bands (RGB) , Multispectral – 4+ bands (e.g. RGBNIR) ,
Hyperspectral – hundreds of bands
3. Temporal (time of day/season/year) Revisit period for satellites – how often
can you make a measurement for the same area • Leaf on/leaf off • Tidal stage
• Seasonal differences • Repetivity of 24 days to year .
4. Radiometric (color depth) Every time an image is acquired by a sensor,
its sensitivity to the magnitude of the electromagnetic energy determines the
radiometric resolution. The finer the radiometric resolution of a sensor, the
more sensitive it is to detecting small differences in reflected or emitted energy

Image Interpretation
Image interpretation ( photo-interpretation) is defined as the extraction of
qualitative and quantitative information in the form of a map, about the shape,
location, structure, function, quality, condition, relationship of and between
objects, etc. by using human knowledge or experience.
Image interpretation in satellite remote sensing can be made using a single scene
of a satellite image, while usually a pair of stereoscopic aerial photographs are
used in photo-interpretation to provide stereoscopic vision using, for example, a
mirror stereoscope. Such a single photo-interpretation is discriminated from stereo
photo-interpretation
Elements of Image Interpretation
1. X,Y location x,y coordinate: longitude and latitude or meters easting and
northing in a UTM map grid
2. Size Length, width, perimeter, area (m2) small, medium (intermediate), large
3. Shape An object’s geometric characteristics: linear, curvilinear, circular,
elliptical, radial, square,rectangular, triangular, hexagonal, pentagonal, star,
amorphous, etc.

Image Interpretation
Elements of Image Interpretation
4. Shadow Caused by solar illumination from the side Tone/color Gray tone: light
(bright), intermediate (gray),dark (black)
5. Color: HIS = intensity, hue (color), saturation; RGB = red, green, blue
6. Texture Characteristic placement of objects on the ground: systematic, random,
linear, curvilinear, rectangular, circular, etc.
7. Pattern Spatial arrangement of objects on the ground: systematic, random,
linear, curvilinear, rectangular, circular, etc
8. Height/depth : z-elevation (height), depth (bathymetry),
9. Volume : volume (m3),
10. Slope/aspect : slope , aspect
11. Site : elevation, slope, aspect, exposure, adjacency to water, transportation,
utilities
12. Situation : objects are placed in a particular order or orientation relative to one
another
13. Association : related phenomena are usually present When you find a certain
activity or phenomena, you almost invariably encounter related or associated
features or activities. http://www.frontdesk.co.in/forum

Georectification
Georectification is the process by which a remotely sensed raster image (e.g. an
aerial photograph, a satellite image, geophysics results, or even a scanned map) is
linked in to a coordinate system so that it can be accurately located onto a map.
Geographic coordinate system (GCS) is
a system that uses a three-dimensional spherical
surface to determine locations on the Earth. Any
location on Earth can be referenced by a point
with longitude and latitude coordinates
Georectification means taking an image that is in
its original geometry, and putting it into a map
projection. There are different ways to do this.
Perhaps the most common way is to identify a set
of points in the image for which the latitude and
longitude or map coordinates are known, and use
them to warp the image into a map projection.

Geodetic datum
Geodetic datum is a reference from which spatial measurements are made. In
surveying and geodesy, a datum is a set of reference points on the earth's surface
against which position measurements are made, and (often) an associated model of
the shape of the earth (reference ellipsoid) to define a geographic coordinate system.
A datum is a model of the earth
that is used in mapping. The
datum consists of a series of
numbers that define the shape
and size of the ellipsoid and it's
orientation in space. A datum is
chosen to give the best possible
fit to the true shape of the Earth.

Map Projections
Projection : Projections is attempt to portray (a portion of) the earth on a flat surface
From spherical coordinate system to a planar (Cartesian) coordinate system. Always
lead to distortions
Cylindrical
Conical
Planer
Type of projection

Type of Map Projection
Grouping by preserved properties:
conformal projection : preserves local angles and
shapes
equivalent projection : represents areas in
correct relative size
equidistant projection : maintains consistency of
scale for certain distances
azimuthal projection : retains certain accurate
directions
… but never conformal and equivalent
equidistantequivalentConformal
Cylindrical projections

UTM-Zone
The UTM system divides the Earth into 60 zones, each 6° of longitude in
width. Zone 1 covers longitude 180° to 174° W;

UTM
U : universal (60 projection zones of 6 degree latitude)
T : transverse (cylinder axis in Equator plane)
M: Mercator projection
• 1 Central line per zone
• 2 standard lines per zone (180 km to the west and the east of central line)
• False Easting and False Northing

Georeferencing
Georeferencing is the process of assigning real-world coordinates to each pixel
of the raster. Many times these coordinates are obtained by doing field surveys -
collecting coordinates with a GPS device for few easily identifiable features in
the image or map.
Raster data is commonly obtained by scanning maps or collecting aerial
photographs and satellite images. Scanned map datasets don't normally contain
spatial reference information (either embedded in the file or as a separate file).
With aerial photography and satellite imagery, sometimes the location
information delivered with them is inadequate, and the data does not align
properly with other data you have. Thus, to use some raster datasets in
conjunction with other spatial data, we may need to align or georeference them
to a map coordinate system.
When we georeference raster data, we define its location using map
coordinates and assign the coordinate system of the data frame. Georeferencing
raster data allows it to be viewed, queried, and analyzed with other geographic
data.

Geometric Distortions
Geometric distortion is an error on an image, between the actual image
coordinates and the ideal image coordinates which would be projected
theoretically with an ideal sensor and under ideal conditions.
Geometric distortions are classified into internal distortion resulting from the
geometry of the sensor, and external distortions resulting from the attitude of
the sensor or the shape of the object.
internal distortionhttp://www.frontdesk.co.in/forum

Geometric Distortions
External distortion
The geometry of along-track scanner
imagery is similar to that of an aerial
photograph for each scan line as
each detector essentially takes a
"snapshot" of each ground
resolution cell. Geometric variations
between lines are caused by random
variations in platform altitude and
attitude along the direction of flight.
They too exhibit relief displacement (A), similar to aerial
photographs, but in only one direction parallel to the
direction of scan. There is no displacement directly below the
sensor, at nadir. As the sensor scans across the swath, the top
and side of objects are imaged and appear to lean away from
the nadir point in each scan line. Again, the displacement
increases, moving towards the edges of the swath.
Images from across-track scanning systems exhibit two main types of geometric distortion.
Another distortion (B) occurs due to the rotation of the scanning optics.http://www.frontdesk.co.in/forum

Image transformations
Image transformations typically involve the manipulation of multiple bands of data,
whether from a single multispectral image or from two or more images of the same area
acquired at different times (i.e. multitemporal image data). Either way, image
transformations generate "new" images from two or more sources which highlight
particular features or properties of interest, better than the original input images.
Basic image transformations apply simple arithmetic
operations to the image data. Image subtraction is often
used to identify changes that have occurred between
images collected on different dates.
Image division or spectral ratioing is one of the most common
transforms applied to image data. Image ratioing serves to
highlight subtle variations in the spectral responses of various
surface covers. By ratioing the data from two different spectral
bands, the resultant image enhances variations in the slopes of
the spectral reflectance curves between the two different spectral
ranges that may otherwise be masked by the pixel brightness
variations in each of the bands.http://www.frontdesk.co.in/forum

Image segmentation
Image segmentation is the process of partitioning a digital image into multiple
segments (sets of pixels, also known as super pixels). The target of
segmentation is always to simplify and/or change the representation of a
graphic into something that is more meaningful and simpler to analyze. Image
segmentation is normally used to locate objects and boundaries (lines, curves,
etc.) in images.

GIS for Urban and Regional Planning
Planners require solutions that address day-to-day work needs while also
fostering the ability to effectively predict and respond to chronic urban
problems and future market fluctuation. The success of planners in combating
chronic urban problems is largely determined by their ability to utilize effective
tools and planning support systems that allow them to make informed decisions
based on actionable intelligence.
Today, planners utilize GIS around the world in a variety of applications. GIS is
being used as a platform to help planners reach their goals of creating livable
communities and improving the overall quality of life while protecting the
environment and promoting economic development. GIS tools can provide the
necessary planning platform for visualization, modeling, analysis, and
collaboration.

GIS for Urban and Regional Planning
GIS allows for multiple criteria evaluation (MCE). This analysis is mainly
characterized by allocating weights to assessment criteria for suggesting and
ranking alternatives. GIS spatial planning support tools have an important
advantage—changing the valuation criteria to visually illustrate and depict the
implications of different spatial decisions and alternatives is convenient. The
capabilities needed for decision making readily available in a single system make
GIS a great tool for integrating in planning processes. GIS spatial analytical tools
can be used to effectively shape decisions that foster urban growth
management

Reference
1. https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/earthsciences/pdf/r
esource/tutor/fundam/pdf/fundamentals_e.pdf
2. http://wtlab.iis.u-tokyo.ac.jp/wataru/lecture/rsgis/
3. UTM Grid Zones of the World http://www.dmap.co.uk/utmworld.htm
4. Using UTM Coordinate system http://www.maptools.com/UsingUTM/

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