Use of IOT in Water Resources Management Sector

 1.INTRODUCTION

Today, humanity confronts numerous critical challenges, with water scarcity being one of the most alarming. The Earth's resources are finite and may prove inadequate for a continually growing population.  The United Nations and the World Bank project that nearly 40% of the global population is impacted by water scarcity, and by 2030, an estimated 700 million individuals may be displaced owing to drought.  Numerous major cities, including Sao Paulo, Bangalore, Mexico City, Cairo, Beijing, Jakarta, Moscow, Istanbul, London, and Tokyo, are anticipated to experience drought in the near future.  The ever-increasing population, restricted groundwater resources, limitations on rains, intermittent drought conditions, and substantial water demands for agriculture, industry, and daily domestic activities have rendered water the most invaluable resource.  Global urban water scarcity is projected to become a critical issue by 2050, with approximately 50% of the urban population residing in water-scarce locations.

                                            

Fig. 1: Projected water scarcity across the globe by 2025

It is anticipated that over 40% of the Indian population will lack access to sufficient drinking water by the year 2030. UN-endorsed projections indicate that by 2030, freshwater demand will exceed availability by 40% as a result of climate change, population growth, and human activities. It is evident that our natural water sources and groundwater are limited, and our water supply and distribution infrastructure is inefficient. Unfortunately, there is no singular solution to tackle the issues of the water crisis  The Internet of Things (IoT) is progressing swiftly due to recent advancements in wireless technology and embedded devices, particularly the development of low-power microcontrollers that are ideal for remotely distributed IoT systems, allowing them to connect and function for prolonged durations without maintenance. Transforming IoT into a necessity rather than a luxury requires data aggregation for military systems. The number of IoT devices rose from 8.4 billion in 2017 to an expected 30 billion by 2020 Wireless mechatronic devices for support and personal care are poised to gain popularity in residential environments, offering significant advantages in assistive healthcare, particularly for the elderly and disabled populations [A water monitoring and control system leveraging Wireless Sensor Networks (WSN) was created for environmental protection, employing ZigBee, GSM, Xbee, mote WiFi, and TCP/IP for data transmission  This review study analyzes several components and approaches for water management and quality system regulation through IoT, encompassing sensors, controllers, and IoT platforms. There is no consensus on the criteria that should be employed to evaluate different characteristics of water.

Fig. 2: Smart Water Management System (SWMS)

2. SMART WATER MANAGEMENT SYSTEM

The primary purpose of the Smart Water Management System is to deliver adequate water to consumers at a fair cost while maintaining water quality standards. Water distribution and management is a challenging issue due to constrained water resources. The Smart Water Management System aims to ensure the rational and sustainable utilization of water resources by adhering to certain overarching objectives. Avoiding or limiting water wastage entails the conservation of water resources. This is particularly crucial during periods of elevated water use for agricultural and industrial operations, as the potential for water wastage increases if not well regulated and monitored. Techniques such as precision agriculture, intelligent irrigation, agricultural water management, and automated water meter reading are prevalent for controlling and reducing water wastage. allocation of water throughout communities, municipalities, structures, and industrial facilities according to demand and established standards can provide enough water supply for all users. Water pressure regulators and intelligent sensors are employed in several regions to guarantee effective water delivery. This ensures effective and optimal water distribution. Effective water leakage management: Water leakage in piping systems results in the wastage of millions of gallons annually. Controlling water leakage is essential to minimize water wastage and prevent unexpected calamities. Automated water meter readings and water leakage detection systems are employed to mitigate and manage water leakage. 

3. FEATURES OF THE SMART WATER MANAGEMENT SYSTEM:

The Smart Water Management System has demonstrated its significance by facilitating the efficient management and distribution of existing water resources. Its capabilities extend beyond mere water supply distribution and control. The typical Smart Water Management System encompasses the following functionalities:

• Intelligent regulation of water accumulation, storage, distribution, purification, and recycling

• Control of water motors to manage supply

• Monitoring of water supply

• Activation and deactivation of water supply

• Regulation and control of water pressure

• Quantification of water through automatic metering

• Support for the Smart Irrigation System in meeting the water requirements of green areas

• Alerts and notifications for warnings, alarms, and disaster scenarios

• Real-time water data analysis encompassing information regarding

4 SMART WATER MANAGEMENT AND SERVICES

The diversity of drinking water sources and their variations are determined by regional features  Some rely on rivers, while others depend on the extraction of groundwater and alternative sources.  ICT methodologies are employed to acquire surface water sources, such as rivers, and to ascertain their depths and areas   Remote sensing technologies and geographic information systems (GIS) software can enhance the exploration process by utilizing satellite and aircraft imagery.  Constructing spatial databases and performing requisite analyses to achieve practical outcomes with reductions in effort, time, and cost relative to conventional technical methodologies of research and exploration   Additionally, several approaches are employed for groundwater investigation, including remote sensing and geographic information systems.

5 INTERNET OF THINGS (IOT)

The development of the Internet of Things (IoT) facilitates connecting devices equipment through the internet, which would be very useful in the automation of the distribution of water and malfunctions or leakage monitoring The principal architecture for IoT comprises three layers: the physical layer, the network layer, and the application layer At the physical layer, sensors collect data from the outside environment, turn that data into usable information. Well, time-sensitive data should be processed the moment they are collected  Otherwise, the data has to be stored in the cloud to avoid network congestion. The data is collected at the network level and converted into digital streams for data processing  The user-facing layer is responsible for delivering specific services to the user. 

6 SENSORS

A variety of sensors for water monitoring are accessible in electronic retail outlets.  Examples of such sensors include constructed sensors, capacitive sensors, turbidity sensors, and soil moisture sensors, among others 

1.     The constructed sensor is of the float type.  The sensor comprises an energy panel and a transmission module, including a solar cell and a lithium-ion battery   The output of this sensor module will be directly connected to the microcontroller without the need for extra signal processing circuitry 

3.     The capacitive sensor is employed for water level measurement.  This sensor has advantages such as low power consumption, linearity, affordability, ease of installation, and suitability for harsh situations 

4.     The turbidity sensor assesses water quality by monitoring sedimentation or opacity   It is utilized to assess water quality in rivers and streams, monitor wastewater and effluent, control settling ponds, and conduct laboratory research.  This liquid sensor offers both analog and digital signaling types 

5.     The soil moisture sensor is a basic breakout device designed to monitor humidity in soil and analogous materials [27].  The soil moisture sensor is relatively user-friendly.  The two sizable exposed pads function as sensor samples, collectively operating as a variable resistor 

7 WIRELESS COMMUNICATION TECHNOLOGY

Wireless technology is used from the controller to the cloud for communicating between the sensor and the controller. Different technologies have been used in any collaboration situation. For the sharing of information, wireless networking technology is also used. Sensors are remotely connected to the microcontroller by either the Zigbee protocol or URAT protocol in the sensors-controller communication. ZigBee is a technology for wireless transfer. It is intended for control systems with multiple channels. Also, alarm and lighting control and has low energy consumption. ZigBee builds on the physical layer of access control and media defined for low-rate WPANs under IEEE standard. Zigbee Protocol is applied in smart water systems when the sensors are located remotely from the control system to communicate between the sensor nodes and the controller. Controller-centralized data storage communications are carried out in long-range communication standards such as 3G and the internet. Some of the earlier work is intended to alert the user to water quality in SMS. The proposed systems necessitate using an additional SIM card for the GPRS module attached to the controller. The disadvantages of these schemes are the additional costs for SIM card operation. Furthermore, the user location is incapable of storing or retrieving vast quantities of data 

 Arduino Shields are specifically engineered for novices to simplify the connection of components and to augment hardware resources.  Arduino is prevalent mainly owing to its characteristics: an autonomous platform, affordability relative to other microcontrollers, open-source hardware and software, and user-friendly programming using the Arduino IDE. Zigbee facilitates communication among various nodes (sensor, base station, and hub).  The software facilitates real-time data management and visualization on a network server utilizing web-based Java toolkits.  The wireless monitoring of field irrigation systems enables remote oversight and management through applications. The emergence of cloud computing presents a feasible solution for the substantial data created by smart sensor networks.  The device is modeled both manually and automatically.  Real-time sensed data are processed on the cloud server for decision-making and behavior monitoring.  The user can oversee the farm's regulatory actions and manage irrigation using the farmers' mobile phones via the Android application. The system comprises a Mamdani fuzzy controller that gathers environmental variables, including soil and temperature sensors, and subsequently employs fuzzy rules to regulate the water flow from the pump, ensuring timely and suitable irrigation.  This may be developed and coded via MATLAB.  A strategy to provide an educated irrigation solution for water conservation and enhanced irrigation management in regions experiencing high water stress was characterized by fuzzy logic and IoT technology.  The proposed fuzzy controller utilizes trapezoidal and triangular component functions based on Mamdani fuzzification to effectively ascertain the irrigation duration and timing for a specific crop.  The fumigation control application-maintained soil moisture above a specified threshold, ensuring gradual fluctuations that prevent frequent device fatigue while conserving water and electricity.  A substantial ZigBee wireless network was employed to monitor the device in real-time. Currently, the preservation of clean water supplies is more challenging globally.  Utilizing a smart water meter to regulate water resources, Singaporeans can preserve water for future generations.  Sensors will facilitate the monitoring of hydraulic data, as well as automatic control and alert notifications utilizing Cloud technology.  A thorough assessment of this study will enable one to undertake significant action.  Consequently, they advocate for an advanced water metering system to be utilized by citizens in Pakistan and globally.  This system will decrease water wastage.  We advocate for serverless architecture because to its potential for rapid adoption and large-scale implementation. In conclusion, based on all of this discussion, an in-depth analysis of the investigated articles supports the readers in identifying the main challenges, relevant recommendations, and future directions for IoT applications for smart water management. utilization of real-time input data from IoT devices   and Android phone was utilized to remotely oversee and regulate the drips from the smart farm irrigation system. 

8 CONCLUSIONS

 Intelligent water management is a technique intended to gather significant and actionable data regarding a city's water supply, pressure, and distribution.  The primary objective is to ensure the proper management of facilities and electricity utilized for water transportation. Economic expansion, climatic change, and population growth impact the accessibility of water supplies.  Information and communication technology play a pivotal part in this matter through various technologies that enhance water conservation, regulate water quality, and facilitate water management. Contemporary SWMS are sophisticated and highly automated systems in comparison to conventional water management systems.  The SWMS extends beyond mere water management.  It offers critical insights on water consumption, water waste, water recycling, and future water needs.  SWMS solutions contribute to the protection of environmental and public health, enhance water management and security, and mitigate unnecessary water wastage.  In addition, SWMS, with other tools like GIS, continuously seeks to track water movement across geographical areas, thereby identifying new water sources. It plays a crucial role in rainfall collecting, water recycling, and the proper disposal of wastewater.  Numerous intelligent technologies exist for water services, encompassing exploration, technical methodologies, filtration, and processing, among others. This review research study intended to examine proactive strategies for the development of Smart Water Applications. In addressing water shortage and its associated challenges, the Smart Water Management System has transitioned from a desirable feature to a fundamental service for Smart Cities. 

 

Use of Agri-Waste in Production of Sustainable Construction Materials

 India generates 500 million tonnes of crop residue annually, according to

 the Union Ministry of New and Renewable Energy. Crop residue is typically used as fodder

 and fuel for domestic and industrial purposes. A surplus of 140 million tonnes, however,

 reportedly remains unattended, out of which 92 million tonnes is burnt each year

Burning crop residue causes severe environmental hazards such as

 greenhouse gas emissions that contribute to global warming, increased

 particulate matter and smog that lead to health hazards and loss of biodiversity.

Thus far, most government interventions have mainly focused on energy production 

out of crop residue, particularly biogas production. 

But development of bio-composites using agricultural residues such as 

rice husks, stalks of most cereal crops, and coconut fibers is also gaining attention.

CSIR-Advanced materials and processes research institute (AMPRI), Bhopal, 

has developed a technology for large-scale recycling of 

parali (paddy straw / stubble) and wheat straw for manufacturing 

hybrid green composite particle / fibreboards on a pilot scale

Indian architect Shriti Pandey recently used agro-waste to construct two COVID-19 care facilities in Bihar and Punjab. The facilities were  built of stubble (or leftover pieces of harvested grain) and are fire-proof, solar-powered  and “inherently thermally insulated. ” What’s more, zero water was used during the construction process — 60 percent  of which took place off-site. Pandey’s efforts reinforce the multifaceted benefit of  agro-waste construction; the project was cost-effective,  non-environmentally intrusive and stable in terms of its physical durability and longevity  — not to mention it aided areas with a rising demand for  hospital beds amidst the pandemic. In this case, a positive change  was made for constructors, environmentalists and community members alike . This has to be done by empowered government agencies

DRONE TECHNOLOGY IN CONSTRUCTION INDUSTRY

 

Emerging digital technologies seem to enhance productivity while also decreasing the overall duration and expense of construction projects.  Drones have just lately been integrated into the construction industry, despite their extensive application in other sectors such as agriculture, public safety, military operations, scientific research, security surveillance, and mining.  Aerial vehicles have been employed in the construction sector for numerous functions, such as inspecting highways, bridges, roads, cell towers, high mast lighting, wind turbines, power transmission lines, building façades and roofs, surveying and mapping, construction oversight, wetland and environmental assessments, drainage and erosion analysis, traffic monitoring, and emergency services.   serve as a few examples.  Operators can disseminate photos to on-site personnel, internal business staff, and remote subcontractors   UAVs provide critical support and cost efficiency through comprehensive surveillance of remote and difficult-to-access locations.  From this viewpoint, UAVs provide optimal access, while 360° panoramas depict a real-time environment   This comparison can be expanded to include real-time recording, reporting, billing, verification, and planning, alongside construction scheduling and cost estimation  UAVs presently offer a significant degree of automation, enabling access to previously inaccessible areas while collecting vast amounts of data in a brief period.  This, however, is not their exclusive application.   Commercial drones are commonly utilized in the construction industry.  A vast array of drones is available on the market.  Drones can be classified into various categories, such as photography drones, aerial mapping drones, military drones, and surveillance drones, among others.  The optimal classification of drones, conversely, may be established according to aerial platforms.  There are four principal groups of drones classified by the type of aerial platform: fixed-wing drones, multi-rotor drones, single-rotor drones, and fixed-wing hybrid VTOL drones.

 

Fly Ash and Slag based cement in terms of durability performance

 

The strength and durability of concrete structure must go hand in hand. Durability is the ability of a structure to resist weathering action, chemical attack and abrasion, while maintaining minimum strength and other desired engineering properties. The commonly observed processes that are responsible, individually or together, for the deterioration of concrete are carbonation, alkali chloride aggregate reaction (AAR), attack, initiated corrosion of reinforcement, sulfate decalcification or leaching and frost or freeze-thaw action. It is generally accepted that under the optimum conditions of effective blending components, transportation, placing, and curing, the addition of mineral admixtures to concrete improves its resistance toward the deteriorating agents.

When mineral admixtures, such as fly ash (FA) or blast furnace slag (BFS) are used, the strength of concrete can be considered as a result of three principal factors, first accounting for the reduction in the quantity of cement (dilution), second heterogeneous nucleation (physical) and third pozzolanic reaction (chemical). The net result is higher long-term strength and durability of the structure. The structures satisfying the requirement of cost, service life, strength and durability require the use high performance concrete (HPC). Judicious choice of chemical and mineral admixtures reduces the cement content and that results in economical HPC.

The carbonation refers to the precipitation of calcite (CaCO,) as well as other CO,-based solid phases, through the reaction of penetrating atmospheric COz with the calcium ions in the pore solution. The main consequence of carbonation is the drop in the pH of the pore solution of concrete so that the passive layer that usually covers and protects the reinforcing steel against corrosion becomes unstable. The continuous diffusion of CO, inside concrete may also lead to decomposition of calcium silicate hydrate (C-S-H), the principal strength giving phase in concrete. The consequences are loss of strength, shrinkage, cracking and increase in the porosity of concrete. In concrete with mineral admixture, where the amount of calcium hydroxide (CH) is reduced due to pozzolanic or cementitious reaction, the carbonation is dependent on permeability and the resultant lower permeability hinders the ingress of COz:

The aggregate containing certain dolomitic or siliceous minerals react with soluble alkalies in concrete and sometimes result in detrimental expansion, cracking and the premature loss of serviceability of concrete structures affected. This phenomenon is known as alkali aggregate reaction or AAR. All kinds of concrete structures may be affected, although structures in direct contact with water, such as dams and bridges, are particularly susceptible to AAR. The mineral admixtures replacing cement, such as BFS and FA, mitigate or eliminate AAR in concrete.

Under marine conditions, chloride ions penetrate through porous concrete and build up around the reinforcement and the alkalinity (pH) of the surrounding pore solution falls substantially. At that stage, the protective ironoxide film around reinforcing bars depassivates and cracks, exposing the steel. The exposed steel gets corroded in the presence of water and oxygen, resulting in the formation of expansive corrosion products (rust) that occupy several times the volume of the original steel consumed. The expansive corrosion products create tensile stresses on the concrete surrounding the corroding steel reinforcing bar, leading to cracking and spalling of concrete cover. The addition of FA and BFS to concrete inhibits corrosion of reinforcement, improving the resistance toward chloride penetration and reducing the quantity of free (soluble)chloride in concrete. Besides delaying the initiation, the corrosion propagation period is also extended.

The deterioration of concrete due to external sulfate attack is a commonly observed phenomenon, when structures are exposed to sulfate solutions or built in sulfate bearing soil and/or ground water. All commonly obtained water soluble sulfates are deleterious (Mg > Na> Ca) to concrete, but the effect is severe when it is associated with Mg cations. The concrete with mineral admixtures, exposed to Na, SO, environment, in general, shows lower expansion.

it is attributed to the lower content of CH and the formation of secondary C-S-H due to pozzolanic/ cementitious reactions, with the addition of FA and BFS. The lower availability of CH in hardened concrete is believed to create a negative effect, during magnesium sulfate attack. However, that is often offset by the reduced permeability and densification caused by the use of mineral admixtures. The decalcification described by dissolution of otesta lss usually CH (also called portlandite) and C-S-H in hydrated cement systems exposed to water. It results in surface deposits of CaCO3 termed efflorescence, and secondary precipitations of monosulfate, ettringite and calcite, deep within concrete.

The efflorescence or surface deposits develop on new constructions with Portland cement concrete masonry units, including bricks and tiles, which have been bonded with Portland cement. It is normally not damaging but aesthetically undesirable. It has negative effect on the compressive strength of concrete. The use of mineral admixtures, combined with adequate curing, decreases the permeability of concrete leaching and decalcification. It is relevant to hydraulic structures, and radioactive disposal facilities, wherein long-term stability must be guaranteed.

Methods Of Design Of Concrete Structures

 Introduction: A structure refers to a system of connected parts used to support forces (loads). Buildings, bridges and towers are examples for structures in civil engineering. In buildings, structure consists of walls floors, roofs and foundation. In bridges, the structure consists of deck, supporting systems and foundations. In towers the structure consists of vertical, horizontal and diagonal members along with foundation.

A structure can be broadly classified as (i) sub structure and (ii) super structure. The portion of building below ground level is known as sub-structure and portion above the ground is called as super structure. Foundation is sub structure and plinth, walls, columns, floor slabs with or without beams, stairs, roof slabs with or without beams etc are super structure. Many naturally occurring substances, such as clay, sand, wood, rocks natural fibers are used to construct buildings. Apart from this many manmade products are in use for building construction. Bricks, tiles, cement concrete, concrete blocks, plastic, steel & glass etc are manmade building materials.

Cement concrete is a composites building material made from combination of aggregates (coarse and fine) and a binder such as cement. The most common form of concrete consists of mineral aggregate (gravel & sand), Portland cement and water. After mixing, the cement hydrates and eventually hardens into a stone like material. Recently a large number of additives known as concrete additives are also added to enhance the quality of concrete. Plasticizers, super plasticizers, accelerators, retarders, pazolonic materials, air entertaining agents, fibers, polymers and silica furies are the additives used in concrete. Hardened concrete has high compressive strength and low tensile strength. Concrete is generally strengthened using steel bars or rods known as rebars in tension zone. Such elements are 'reinforced concrete' concrete can be moulded to any complex shape using suitable form work and it has high durability, better appearance, fire resistance and economical. For a strong, ductile and durable construction the reinforcement shall have high strength, high tensile strain and good bond to concrete and thermal compatibility. Building components like slab walls, beams, columns foundation & frames are constructed with reinforced concrete. Reinforced concreted can be in-situ concreted or precast concrete.

Photogrammetric Surveying

 Photogrammetric Surveying

It is the branch of surveying in which maps are prepared from photographs taken from

ground or air stations. Photographs are also being used for interpretation of geology,

classification of soils, crops, etc. 

The art, science, and technology of obtaining reliable information about physical

objects and the environment through process of recording, measuring, and interpreting

photographic images and patterns of recorded radiant electromagnetic energy and

phenomenon.

Originally photogrammetry was considered as the science of analysing only

photographs. 

Advantages and Disadvantages: 

Some advantages of photogrammetry over conventional surveying and mapping methods are: 

 It provides a permanent photographic record of conditions that existed at the time the

aerial photographs were taken. Since this record has metric characteristics, it is not only

a pictorial record but also an accurate measurable record. 

 If information has to be re-surveyed or re-evaluated, it is not necessary to perform

expensive field work. The same photographs can be measured again and new

information can be compiled in a very timely fashion. Missing information, such as

inadequate offsets for cross sections, can be remedied easily. 

 It can provide a large mapped area so alternate line studies can be made with the same

data source can be performed more efficiently and economically then other

conventional methods. 

 It provides a broad view of the project area, identifying both topographic and cultural

features. 

 It can be used in locations that are difficult, unsafe, or impossible to access.

Photogrammetry is an ideal surveying method for toxic areas where field work may

compromise the safety of the surveying crew. 

 An extremely important advantage of photogrammetry is that road surveys can be done

without closing lanes, disturbing traffic or endangering the field crew. Once a road is

photographed, measurement of road features, including elevation data, is done in the

office, not in the field. 

 Intervisibility between points and unnecessary surveys to extend control to a remote

area of a project are not required. The coordinates of every point in the mapping area

can be determined with no extra effort or cost. 

 The aerial photographs can be used to convey or describe information to the public,

State and Federal agencies, and other divisions within the Department of

Transportation. 

Some disadvantages are: 

 Weather conditions (winds, clouds, haze etc.) affect the aerial photography process and

the quality of the images. 

 Seasonal conditions affect the aerial photographs, i.e., snow cover will obliterate the

targets and give a false ground impression. Therefore, there is only a short time

normally November through March, that is ideal for general purpose aerial

photography. A cleared construction site or a highway that is not obstructed by trees, is

less subjected to this restriction. These types of projects can be flown and photographed

during most of the year. 

 Hidden grounds caused by man-made objects, such as an overpass and a roof, cannot

be mapped with photogrammetry. Hidden ground problems can be caused  by tree

canopy, dense vegetation, or by rugged terrain with sharp slopes. The information

hidden from the camera must be mapped with other surveying methods. 

 The accuracy of the mapping contours and cross sections depends on flight height and

the accuracy of the field survey. 

History of Photogrammetry: 

1851: French officer Aime Laussedat develops the first photogrammetrical devices and

methods. He is seen as the initiator of photogrammetry. 

1858: The German architect A. Meydenbauer develops photogrammetrical techniques for

the documentation of buildings and installs the first photogrammetric institute in 1885 

(Royal Prussian Photogrammetric Institute). 

1885: The ancient ruins of Persepolis were the first archaeological object recorded

photogrammetrically. 

1889: The first German manual of photogrammetry was published by C. Koppe. 

1911: The Austrian Th. Scheimpflug finds a way to create rectified photographs. He is

considered as the initiator of aerial photogrammetry, since he was the first succeeding to 

apply the photogrammetrical principles to aerial photographs 

1913: The first congress of the ISP (International Society for Photogrammetry) was held

in Vienna. 

1980: Due to improvements in computer hardware and software, digital photogrammetry

is gaining more and more importance. 

1996: 83 years after its first conference, the ISPRS comes back to Vienna, the town,

where it was founded. 

Classification of Photogrammetry: 

Photogrammetry is divided into different categories according to the types of photographs or

sensing system used or the manner of their use as given below: 

I. On the basis of orientation of camera axis:  

a. Terrestrial or ground photogrammetry 

When the photographs are obtained from the ground station with camera axis horizontal

or nearly horizontal         

b. Aerial photogrammetry

If the photographs are obtained from an airborne vehicle. The photographs are 

called vertical if the camera axis is truly vertical or if the tilt of the camera axis is less

than 3 degree

. If tilt is more than (often given intentionally), the photographs are

called oblique photographs. 

II. On the basis of sensor system used:  

     Following names are popularly used to indicate type of sensor system used:  

 Radargrammetry: Radar sensor  

 X-ray photogrammetry: X-ray sensor  

 Hologrammetry: Holographs  

 Cine photogrammetry: motion pictures  

 Infrared or colour photogrammetry: infrared or colour photographs  

III. On the basis of principle of recreating geometry:  

When single photographs are used with the stereoscopic effect, if any, it is

called Monoscopic Photogrammetry.  

If two overlapping photographs are used to generate three dimensional view to create relief

model, it is called Stereo Photogrammetry. It is the most popular and widely used form of

photogrammetry.  

IV. On the basis of procedure involved for reducing the data from photographs: 

Three types of photogrammetry are possible under this classification:  

a. Instrumental or Analogue photogrammetry: It involves photogrammetric

instruments to carry out tasks.  

b. Semi-analytical or analytical: Analytical photogrammetry solves problems by

establishing mathematical relationship between coordinates on photographic image and

real world objects. Semi-analytical approach is hybrid approach using instrumental as

well analytical principles.  

c. Digital Photogrammetry or softcopy photogrammetry: It uses digital image

processing principle and analytical photogrammetry tools to carry out photogrammetric

operation on digital imagery.  

V. On the basis of platforms on which the sensor is mounted:

If the sensing system is space borne, it is called Space Photogrammetry, Satellite 

Photogrammetry or Extra-terrestrial Photogrammetry. Out of various types of the

photogrammetry, the most commonly used forms are Stereo Photogrammetry

utilizing a pair of vertical aerial photographs (stereo pair) or terrestrial photogrammetry

using a terrestrial stereo pair.   

Application of Photographic Survey: 

Photogrammetry has been used in several areas. The following description give an overview

of various applications areas of photogrammetry  

a. Geology: Structural geology, investigation of water resources, analysis of thermal patterns

on earth's surface, geomorphological studies including investigations of shore features.  

• Stratigraphic studies 

• General geologic applications 

• Study of luminescence phenomenon 

• Recording and analysis of catastrophic events

• Earthquakes, floods, and eruption.  

b. Forestry:  Timber inventories, cover maps, acreage studies 

c. Agriculture: Soil type, soil conservation, crop planting, crop disease, crop-acreage.

d. Design and construction: Data needed for site and route studies specifically for 

alternate schemes for photogrammetry. Used in design and construction of dams,

bridges, transmission lines.  

e. Planning of cities and highways: New highway locations, detailed design of

construction contracts, planning of civic improvements.  

f. Cadastre: Cadastral problems such as determination of land lines for assessment of

taxes. Large scale cadastral maps are prepared for reapportionment of land. 

g. Environmental Studies:

h. Land-use studies.

i. Urban area mapping.

j.  Exploration: To identify and zero down to areas for various exploratory jobs such as 

oil or mineral exploration. 

k. Military intelligence: Reconnaissance for deployment of forces, planning manoeuvres, 

assessing effects of operation, initiating problems related to topography, terrain

conditions or works.  

l. Medicine and surgery: Stereoscopic measurements on human body, X-ray

photogrammetry in location of foreign material in body and location and examinations

of fractures and grooves, biostereometrics.  

m. Mountains and hilly areas can be surveyed easily.

n. Miscellaneous 

Classification of Photographs:    

The following paragraphs give details of classification of photographs used in different

applications     

A. On the basis of the alignment of optical axis  

 Vertical: If optical axis of the camera is held in a vertical or nearly vertical position. 

 Tilted: An unintentional and unavoidable inclination of the optical axis from vertical

produces a tilted photograph.  

 Oblique: Photograph taken with the optical axis intentionally inclined to the vertical.

Following are different types of oblique photographs:  

i.  High oblique: Oblique which contains the apparent horizon of the earth. 

ii. Low oblique: Apparent horizon does not appear.  

iii. Trimetrogon: Combination of a vertical and two oblique photographs in which

the central photo is vertical and side ones are oblique. Mainly used for

reconnaissance. 

iv. Convergent: A pair of low obliques taken in sequence along a flight line in

such a manner that both the photographs cover essentially the same area with

their axes tilted at a fixed inclination from the vertical in opposite directions in

the direction of flight line so that the forward exposure of the first station forms

a stereo-pair with the backward exposure of the next station.  

ASTRONOMICAL SURVEYING

 ASTRONOMICAL SURVEYING

Celestial Sphere. 

The millions of stars that we see in the sky on a clear cloudless night are all at varying distances from us. Since we are concerned with their relative distance rather than their actual distance from the observer. It is exceedingly convenient to picture the stars as distributed over the surface of an imaginary sphericalsky having its center at the position of the observer. This imaginary sphere on which the star appears to lie or to be studded is known as the celestial sphere. The radius of the celestial sphere may be of any value - from a few thousand metres to a few thousand kilometers. Since the stars are very distant from us, the center of the earth may be taken as the center of the celestial sphere.

Zenith, Nadir and Celestial Horizon.

 The Zenith (Z) is the point on the upper portion of the celestial sphere marked by plumb line above the observer. It is thus the point on the celestial sphere immediately above the observer's station. The Nadir (Z') is the point on the lower portion of the celestial sphere marked by the plum line below the observer. It is thus the point on the celestial sphere vertically below the observer's station. Celestial Horizon. (True or Rational horizon or geocentric horizon): It is the great circle traced upon the celestial sphere by that plane which is perpendicular to the Zenith-Nadir line, and which passes through the center of the earth. (Great circle is a section of a sphere when the cutting plane passes through the center of the sphere)

Terrestrial Poles and Equator, Celestial Poles and Equator. 

The terrestrial poles are the two points in which the earth's axis of rotation meets the earth's sphere. The terrestrial equator is the great circle of the earth, the plane of which is at right angles to the axis of rotation. The two poles are equidistant from it. If the earth's axis of rotation is produced indefinitely, it will meet the celestial sphere in two points called the north and south celestial poles (P and P'). The celestial equator is the great circle of the celestial sphere in which it is intersected by the plane of terrestrial equator.

CO-ALTITUDE OR ZENITH DISTANCE (Z) AND AZIMUTH (A).

It is the angular distance of heavenly body from the zenith. It is the complement or the altitude, i.e. z = (90 - θ) degree. The azimuth of a heavenly body is the angle between the observer's meridian and the vertical circle passing through the body