In: Civil Engineering
Please don't leave any questions to answer. If you are waiting for great feedback then that should be me. This questions are from surveying and spatial science
a). You are working in the Environmental Management section of a Local Government Council. Your Local Government area includes approximately 100 km of coastline, comprising a mix of beaches, coastal dunes, rocky shores and headlands. Some regions of the coastline are considered highly vulnerable to the effects of climate change. Along the coastline there are beachside communities, agricultural activities and natural bushland.
Carefully consider the environmental monitoring that may need to be undertaken in order for your Council to measure and manage the impacts of climate change. List and describe the surveying and spatial technologies and methods that might be required to collect, manage and analyse the spatial data required by the Council.
b). You have been employed by a company that provides services to the farming/agriculture sector: including grazing (cattle and sheep), broad acre cropping (grains), and intense, high-value horticulture (irrigated crops such as lettuce, cherries, stone fruit). The company has identified spatial technologies as an emerging opportunity to provide new services to their clients. List and describe four examples of how different spatial technologies can be applied to farming/agricultural business
Answer 1- surveying and spatial technologies and methods that
might be required to collect, manage and analyse the spatial data
required by the Council in coastal area are as follow-
As the intersection of land and sea, coastal zones are complex and
variable. The traditional means of coastal zone research have
certain limitations. Both the monitoring means and the monitoring
intensity struggle to meet the demand of real-time monitoring due
to coastal zone development, environmental changes, and disasters.
Among the modern methods for monitoring terrestrial ecosystems,
remote sensing is of primary importance due to its ability to
provide synoptic information over wide areas with high acquisition
frequencies .
1 . Remote sensing- Remote sensing has been used in resource
development, the planning and management of the coastal zone, the
monitoring of shoreline changes, and the understanding of physical
processes in the coastal environment with geographic information
systems (GIS )
Remote sensing technology acquires and records information without
coming into direct contact with an object. Remote sensing was
redefined as the science and technology of Earth observation,
including space to Earth observation, aerial observation, and field
monitoring. From this perspective, remote sensing data can be
divided into data on a global scale, a regional scale, and a local
scale.
Global-scale satellites include static meteorological satellites,
such as the GOES-8, the GOES-10, and the GMS meteorological
satellite. The GOES-8 and the GOES-10 are the stationary satellites
of NOAA. Their purposes are daily weather observations. These
satellites provide a variety of meteorological and
nonmeteorological services and play an important role in the study
of global climate change, weather forecasting, disaster prevention,
and disaster reduction.
Regional-scale data are generally obtained from moderate-resolution
remote sensing images, such as MODIS sensor and Landsat satellites.
MODIS is an important sensor equipped with Terra and Aqua
satellites. Its multispectral data can reflect the information of
land surface condition, ocean colour, phytoplankton, biological
geography, chemistry, atmospheric water vapour, aerosol and surface
temperature, atmospheric temperature, and so on. Launched by the
United States, Landsat satellites are primarily used to capture the
remote sensing images of land, including soil organisms and plants.
These satellites provide accurate and dynamic geographical
information sources. Regional-scale data can be used in the
macroscopic analysis of coastal zone changes.
Local-scale satellites are usually used for monitoring in a smaller
scope with high resolutions, such as worldview satellite, airborne
satellites, and unmanned aerial vehicles (UAVs). The benefits of
high spatial and high spectral resolution data are their ability to
match the rich spectral and spatial diversities observed in coastal
systems. For example, The invasion of Spartina alterniflora was
monitored using very high resolution UAV imagery in Beiha. The
results showed that UAV imagery can provide details on the
distribution, progress, and early detection of S. alterniflora
invasion, and the total accuracy was 94.0%.
Based on the spectral types, satellites can be divided into optical
satellites and microwave satellites. Hyperspectral and
multispectral data provide more information for identifying
targets. Unlike optical satellites, microwave satellites can
penetrate through snow, soil, and forest. The benefit of combined
optical and SAR-based approaches in improving classifications over
some coastal habitats was demonstrated.
Currently, remote sensing data are used in various ways: they serve
as input boundary conditions and validation data for numerical
simulation models, they are combined with in situ measurements to
draw sediment transport maps, and they are assimilated in 3D
coastal sediment transport models and in the light forcing of an
ecosystem model.
2 . Geographical information system- GIS is an important and
specific spatial information system. It is the technical system for
the collection, storage, management, operation, analysis, display,
and description of geographic distribution data for the entirety or
a part of the Earth’s surface (including the atmosphere) in support
of computer hardware and software systems. GIS has spatial analysis
capabilities, can store and manage vast amounts of complex spatial
data and attribute data, and can use spatial databases for the
comprehensive analysis of multiple factors with quantity, quality,
and localization. However, it is difficult to achieve attribute
data modelling relying solely on GIS software.
Combining GIS and mathematical models can make modelling easier by
improving accuracy and solving problems effectively. For example,
Anthony et al. used GIS with fuzzy learning vector quantization
(FLVQ) for coastal vegetation classification. The classification
accuracy of FLVQ was comparable to a conventional supervised
multilayer perceptron, trained with backpropagation (KHAT accuracy:
82.82% and 84.66%, respectively; normalized accuracy: 74.60% and
75.85%, respectively), with no significant difference at the 95%
confidence level .An eutrophication model for Bohai Bay based on a
cellular automata-support vector machine (CA-SVM) was established
in by applying the soft computing approach with a large quantity of
remote sensing data to the marine environment. Their comparison
between the optimized model and the basic model indicated that
prediction accuracy was improved by the optimized model. The
spatiotemporal patterns of phosphorus concentrations in a coastal
bay were explored with machine learning models in . GIS spatial
analysis methods, along with mathematical models, can be used to
analyse the interaction between coastal zone changes and the
effects of human activities. These methods are very effective for
coastal zone monitoring.
Various Methods-
Landscape classification-
Remote sensing image classification is an important way to extract
information. Different surface features have different spectral
characteristics. Landscape classification is the clustering of the
same or similar pixels and the assigning of value to each pixel
class through the analysis of spectral characteristics based on
satellite remote sensing images.
Landscape classification is a complex data processing task. Many
factors, such as the spatial resolution of remote sensing images,
different sources of data, and different classification methods,
may influence the accuracy of landscape classification. The
selection of the classification method is critical. Usually,
classification methods can be divided into supervised
classification approaches and unsupervised classification
approaches. Supervised classification approaches identify the class
of each pixel by selecting typical and representative training
samples that the types are known already and training the
classifier to classify the spectral data with the spectral
characteristics of training samples. There are many classifiers,
such as maximum likelihood, minimum distance, the SVM, the
artificial neural network (ANN), and the decision tree.
Unsupervised classification approaches are used to partition a
spectral image into a number of spectral classes based on the
statistical information inherent to the image. Unsupervised
classification approaches merge spectral classes into meaningful
classes based on the size of the similarity between pixels instead
of training samples. The methods of unsupervised classification
include, for example, the k-means algorithm, the iterative
self-organizing data analysis method (ISODATA), and fuzzy
clustering .
Regional scale: Automatic classification and change
detection
On a regional scale, the data most frequently used in landscape
classification and change detection are moderate spatial resolution
remote sensing images, such as land-resource satellite data. Some
traditional landscape classification methods require considerable
labor and prior knowledge, and accuracy cannot be guaranteed. To
reduce human intervention to a minimum and to achieve accurate
classification rapidly, An efficient automatic landscape
classification approach using prior accurate land-cover data as the
background experience was proposed in. This approach is
distinguished from the previous semisupervised findings of
landscape classifiers by adopting prior knowledge. It can be simply
described in two steps: (1) detecting landscape changed pixels from
satellite images compared with a prior landscape map and (2)
classifying the landscape of changed pixels based on pattern
recognition and changed rules.
Automatic collection of training samples
The first phase of this method is sampling, with a purpose of
obtaining pure pixels of landscape classes. The selected training
samples were used to ultimately convey the information to a
three-dimensional feature space. The automatic collection of
training samples is illustrated in Fig. 1.
Diagram of automatic collection of training samples.
Establishment of three-dimensional feature space
Principal component statistical analysis was used to process the
data in all spectral bands of each landscape class, extracted by
the region of interest. The first three principal components were
selected for orthogonal decomposition to construct the
three-dimensional feature space of different landscape classes. The
three-dimensional spectral feature space of different landscape
classes is established in the Fig 2.
Spectral feature spaces of typical landscape types.
Change detection and classification
For each landscape class, all extracted cell spectral data of the
same landscape class were used to calculate the values of the
corresponding feature space. The pixels outside the corresponding
three-dimensional feature space were considered the changed areas.
After the changed pixels of the landscape were obtained, the
satellite images and the three-dimensional feature space were
employed to classify them based on pattern recognition and changed
rules.
Modification of post classification results
There is an inevitable problem that a few individual pixels are
inconsistent with the surrounding landscape class. The modification
of post classification results solved this problem by dilating
operation and eroding operation on the classified results. The
“salt-and-pepper” error is also a common problem. A moving window
with a size of 3×3 pixels was defined to eliminate noise.
Accuracy assessment and time-consuming evaluation
A kappa coefficient and a time-consuming evaluation were adopted to
evaluate the practicability of classification. A kappa value equal
to or greater than 0.61 was considered to be in good agreement.
According to the requirements, a less time-consuming combination of
Pa [accumulation area threshold (Pa) index] and Pbuffer (area
threshold for buffer analysis) or a combination with a time-lapse
rate minimum would form the optimal combination model.
Local scale: Object-oriented classification with high-resolution
image data
With the improvements in satellite sensor resolution,
high-resolution remote sensing imaging has played an important role
in relevant application fields. High-resolution remote sensing
images contain rich information, such as spectral information,
shape information, and texture information. High-resolution remote
sensing images can clearly capture fine features and changes, such
as port construction, roads, ecosystem characteristics, and species
distribution (e.g., mangroves and invasive plant distribution).
Pixel-based classification approaches are primarily based on the
spectral information of pixels to extract feature information, and
they do not make full use of rich spatial information (shape
information and texture information) in the process of
classification. According to the characteristics of high-resolution
images, an object-oriented classification method was proposed in,
which makes full use of spectral, shape, and texture information
and obtain a high precision of classification results.
Object-oriented classification is based on image segmentation to
obtain a homogeneous image object and then analyze the spectrum,
shape, and texture features to classify and extract the feature
information. The main phases of classification are shown in the Fig
3
Object-oriented classification.
Object-oriented remote sensing image classification includes two
key steps: multiresolution segmentation and classification.
Multiresolution segmentation
The multiresolution segmentation region grows and merges the
algorithm and minimizes the average heterogeneity of image objects.
The multiresolution segmentation algorithm consecutively merges
pixels or image objects and is thus a bottom-up segmentation
algorithm based on a pairwise region-merging technique .
Multiresolution segmentation algorithms include three factors: the
band-weighting factor, the heterogeneity factor, and the
segmentation scale. As the segmentation scale increases in size,
the objects grow larger. Heterogeneity is composed of spectroscopy
heterogeneity, shape heterogeneity, spectral weight, and the shape
weight of four variables.
f=wl×hcolor+(1−wl)×hshapef=wl×hcolor+(1−wl)×hshape
where hcolor is spectroscopy heterogeneity, hshape is shape
heterogeneity, wl is spectral weight, and 1-wl is shape
weight.
The multiresolution segmentation is the process of merging image
objects in several loops in pairs starting with a single image
object of one pixel. In each loop, the single image object acts as
a seed to find its best-fitting neighbor in four directions or
eight directions, as shown in Fig 4. If the best neighbor’s
best-fitting neighbor is the seed, then the two pixels are merged
into an image object. If otherwise, the best neighbor as a new seed
begins to look for its own best-fitting neighbor until a pair of
best-fitting image objects are found. The loops continue until the
heterogeneity of each pair of image objects is greater than the
segmentation scale
Multiresolution segmentation
According to the extracted object, the proper parameters are chosen
to achieve the optimal segmentation result with scale 75, shape
0.1, and compactness 0.5 as shown in Fig. 5.
Feature selection
Feature selection is to select the spectral features, shape, and
texture features for classification through the analysis of feature
information, see the analysis result of feature information in Fig.
6. According to the classification targets (landscapes in Table 4),
some features were selected and proper thresholds were set, such as
normalized difference vegetation index (NDVI), mean, shape index,
and brightness.
Classification result
As shown in Fig. 7, the landscape mainly consists of aquafarms,
water area, forest land, industrial land, cultivated land,
residential area, and construction land. The classification result
is reasonable through comparative analysis between the results and
the original image.
Result of classification.
The object-oriented classification method we used in this study
shows a good performance with the total accuracy of 89% and the
kappa coefficient of 0.83. This method provides a high precision
and a reasonable classification result.
Retrieval of eco-environmental parameters based on remote sensing
technique
The parameters of land surface energy and water balance are
important inputs for research on global climate change, crop yield
assessment, and ecological environment evaluations. Remote
sensing-derived radiation, temperature, and other data sets on a
global scale have been used as standardized products in research
and applications. Remote sensing information is convenient and easy
to access over a large area at a low cost.
Energy- and water-balance parameters: solar radiation and
Evapotranspiration (ET)
Solar radiation
Solar radiation is the Earth surface’s most basic and important
source of energy as well as the main driving factor of plant
photosynthesis, transpiration, and soil evaporation land-surface
processes . Solar radiation is responsible for the formation and
evolution of important climate driving forces. Changes in solar
radiation change the temperature, humidity, precipitation,
atmospheric circulation, the hydrological cycle, and other
processes. Solar radiation is an important physical and ecological
parameter in the land surface and atmospheric energy exchange
process. Accurate solar radiation data retrieved from satellite
data help improve net radiation, ET, and other precision
products.
Geostationary meteorological satellite data have often been adopted
as the data source for solar radiation and ET retrieval. GMS-5 data
are easily acquired with a relatively high temporal resolution (1
h). GMS-5 data consist of three types of bands: (1) the visible
(VIS) band with a spatial resolution of 1.25 km and a spectrum
range from 0.55 to 1.05 μm, (2) the thermal infrared (TIR) band
with a spatial resolution of 5 km and a spectrum range from 10.5 to
12.5 μm, and (3) the water vapor (WV) band with a spatial
resolution of 5 km and a spectrum range from 6.2 to 7.6 μm. The VIS
and TIR bands were employed for ET retrieval, and the WV band was
used for calibration and validation.
Net radiation was calculated as the net result of the short-wave
(solar) and long-wave (terrestrial) radiative fluxes, and it is
expressed as a daily average:
In=(1−a)Ig+LnIn=(1−a)Ig+Ln
where a is a surface albedo, which could be derived from the VIS
data of the GMS-5; Ig is the daily average solar irradiation at the
Earth’s surface; and Ln is the net long-wave (thermal) radiation
loss.
Figures 8 and 9 show the spatial distribution of the global and net
solar radiation of Asia in January, April, July, and October 2004,
respectively.
Solar radiation is an important factor in maintaining the Earth’s
climate system and the ecosystem’s energy balance and is the main
source of energy in the ecosystem, which plays an important role in
the process of human development. Many environmental changes are
related to solar radiation . The use of satellite remote sensing
data, particularly the stationary meteorological satellite data for
observing a fixed surface area with the temporal resolution of 1 h,
can greatly compensate for the lack of ground observation data. It
is important to obtain long and continuous region surface solar
radiation to analyze solar radiation’s spatial and temporal
variation of the surface area. The analysis of surface solar
radiation and climate change research will thereby be greatly
facilitated.
ET
Evapotranspiration (ET) is usually understood to be the sum of soil
evaporation and plant transpiration, which is a
soil-plant-atmosphere continuum system and an important process
(SPAC) in water movement. ET is essential to crop growth and the
development of water and energy sources. Ecological systems are an
important link between land surface and hydrological processes,
which are closely related to the strength and size of the
underlying surface of plants. ET can be said to be both a surface
heat-balance component and an important part of water balance. ET
is highly variable across space due to changes in precipitation,
soil hydrological parameters, and vegetation type and density. Its
strong spatial variability across time is due to climate changes at
different times.
Calculation of the sensible heat flux: The sensible heat flux into
the atmosphere is proportional to the temperature difference across
the atmospheric boundary layer (T0-Ta). The simple formulation
is:
H=(ac+ar)(T0−Ta)H=(ac+ar)(T0−Ta)
where ac stands for surface resistance and ar stands for the
resistance of the atmosphere.
Having determined the net radiation (In) and the sensible heat flux
(H), the latent heat flux (i.e., the actual ET in energy units) can
be obtained based on regional energy and water balance:
LE=In−H−GLE=In−H−G
Item G is the heat flux into the soil, which is very small on the
daily time scale, and may be considered a constant.
Figure 10 shows the spatial distribution of the ET of Asia in
January, April, July, and October 2004 and reveals the significant
differences between the distributions of different months of
relative ET space. Relative ET was higher at low latitudes than at
high latitudes and varied across months. Due to the lush plant
growth in July, relative ET is generally high in most of Asia. In
January, in most of Asia, including the South and Southeast Asian
countries, there are low temperatures and generally low relative
ET.
Many ecosystem processes, such as soil moisture changes, vegetation
growth, and nutrient cycling, are closely linked to the ET process.
The ET process is affected by climate, soil characteristics, and
vegetation growth status . Therefore, the calculation of ET reveals
the changes in the time of ET and its impact factors to quantify
the contribution of plant transpiration and soil evaporation to ET.
ET can not only reveal various land-surface (vegetation,
particularly surface) water consumptions [33] but also help us
understand the effect of global warming on the actual ET and water
balance, land surface ecology, and environment. ET can also improve
climate models and accurately simulate climate change, which is
important.
Factors of coastal environment analysis
Coastal zones and shelf seas are influenced by both natural and
socioeconomic conditions. An integrated evaluation criteria system
was set up, which contained nine factors belonging to three
categories: (1) environmental background factors, including
elevation, slope, geomorphological types, accumulated temperature,
and a wetness index; (2) water/land resources, including
precipitation, river density, and land use; and (3) socioeconomic
factors, including railway density, road density, and population
density. However, human life and development may also directly or
indirectly affect costal zones and shelf areas, including
mariculture and marine fishing production, sea pollution, and
others (e.g., building, sports, and travel).
Answer 2 - Different spatial technologies which can be applied
to farming or agriculture business are as follows
Global Positioning Systems
Geographic Information Systems
Variable-rate Application
Remote Sensing
1 . Global positioning system- Global positioning systems (GPS)
use 24 satellite signals to define positions on the earth. The
satellites circle the earth twice a day in six orbital paths. GPS
can be used to georeference soil samples, tillage, planting,
spraying, scouting, and harvesting. For example, GPS is used to
georeference soil sampling and for tractor navigation. The hardware
required for GPS includes a GPS receiver and antenna, a
differential correction signal receiver and antenna, and an
interface.
Soil sampling- Soil sampling is another important part of
site-specific farming. soil properties, such as texture, organic
matter content, and landscape geomorphology, have a considerable
influence on the productivity of soils. A soil inventory needs only
to be taken once for the variation assessment of these time
constant properties. This soil inventory can be done properly by
soil surveying, which combines GPS with the human sensory
capability. Self-surveying is remarkably appropriate for getting
the basic soil information needed at a low cost.
2 . Geographic information system- Geographic information systems
(GIS) are used to input, store, retrieve, analyze,and display
geographic data. The hardware needed for GIS includes a computer,
high-resolution display monitor, digitizer/scanner, plotter/colour
printer, and a floppy disk drive. The software consists of a user
interface, data input, data storage, data output, and data
transformation.
maps generated from using GIScan be used to evaluate site-specific
farming applications. Provincial Survey aerial photographs and GIS
spectrographic software to generate maps to delineate management
zones according to soil colour. Provincial Survey aerial
photographs and GIS spectrographic software can be used to generate
maps to delineate management zones according to soil colour. areas
with low fertility and poor drainage, could be identified and
predictions could be made about where problems are likely to occur
so solutions could be found.
3 . Variable rate application- Variable-rate application (VRA)
requires controllers, which change the application rate on the go,
and actuators, which respond to the controller to regulate
application. Variable-rate applications include applications of
fertilizer, pesticides, and seed. The two methods of VRA are
map-based and sensor-based. Map-based VRA requires GPS, GIS, and
software for producing the maps.
Snyder, et al. (1999) examined the economics of site-specific
nitrogen management for irrigated corn in Kansas. Comparisons were
made of uniform and variable nitrogen management using both soil
sampling and detailed yield maps. Using data from both uniform and
variable rate experiments, a quadratic function was estimated for
each site and each year. Results indicated that there is potential
for profitable use of precision nitrogen management. Variable rate
technology for nitrogen application used less nitrogen than the
uniform management. For that reason, it was determined to be more
profitable in some years while not in others.
4 . Remote Sensing- Remote sensing measures energy reflected and
emitted from objects without actually coming in contact with the
objects. Four properties of remote sensing data that should be
considered when using remote sensing systems include spatial
resolution, spectral response, spectral resolution, and frequency
of coverage. Spatial resolution refers to the size of the smallest
grid cell of the imagery. Spectral response is the sensing system’s
ability to collect and respond to radiation in a spectral band.
Spectral resolution is the ability of a sensing system to
distinguish between different wavelength’s electromagnetic
radiation. Frequency of coverage, also known as temporal
resolution, refers to how often a sensing system is available for
data collection at a particular ground site.
The two main remote sensing platforms are aircraft-based and
satellite-based. Aircraft-based systems provide images with higher
spatial and spectral resolution than data from satellite-based
systems. They are also easier to maintain and have the ability to
provide images with a higher resolution. They can sense areas when
conditions are optimal. In contrast, satellite-based platforms are
in fixed orbits. Cost varies according to image type, image size,
and level of processing.
Remote data are collected by using sensors on airplanes or
satellites to detect electromagnetic radiation emitted or reflected
from objects on the ground. More formally defined, remote sensing
involves obtaining physical data about an object without being in
contact with the object. By using the data acquired through remote
sensing, farmers are able to obtain detailed spatial information
about features in their fields to assist management
decisions.
Remote sensing can be used to measure soil and crop
characteristics. In particular, images produced from remote sensing
can help farmers with planting, fertilizing, irrigating, as well as
other management decisions in the field.