Longitudinal Sectioning

Longitudinal sectioning, also known as profile leveling or profiling, is the process of establishing the elevation of sites on the ground at about regular intervals along a continuous line. Profile levelling is one of the surveyor’s most typical applications of running levels and vertical distance measuring. The data are represented as a profile, which is a representation of a vertical cross section. The primary objective of longitudinal sectioning is to determine the slope, grade, and vertical alignment of the surveyed feature.

• Taking elevation measurements: At regular intervals along the base line, surveyors measure the elevation of the ground surface using an instrument like a leveling instrument or a total station. These measurements are recorded to create a profile of the land.

• Plotting the profile: The collected elevation data is plotted on graph paper or entered into specialized software to create a longitudinal section. The resulting graph shows the variations in ground level along the surveyed line.

Cross Sectioning

Cross sectioning involves the creation of horizontal cross-sectional views of the land perpendicular to the alignment being surveyed. This technique provides valuable information about the terrain’s shape, dimensions, and features at specific locations. Cross sections are particularly useful for designing and analyzing infrastructure elements like roads, canals, or embankments.

• Establishing cross-section lines: Surveyors mark perpendicular lines to the alignment being surveyed at regular intervals. These lines are known as cross-section lines or station lines.

• Taking measurements: Along each cross-section line, surveyors measure the ground level at predetermined intervals using leveling instruments or total stations. Additional measurements may be taken for features such as buildings, utilities, or natural elements.

• Plotting the cross section: The measured data is then plotted on graph paper or entered into specialized software to create a cross section. The resulting diagram provides a detailed view of the land’s features and elevations along the surveyed line.

Applications

Longitudinal and cross sectioning have numerous applications in surveying and civil engineering projects:

• Road construction: Longitudinal and cross sectioning techniques are extensively used in road surveys for designing alignments, establishing grades, and determining cut and fill quantities for earthwork calculations.
• Drainage systems: The creation of longitudinal and cross-sectional profiles helps in designing efficient drainage systems by identifying the natural flow patterns and locating appropriate points for channeling water.
• Utility infrastructure: Surveying utilities, such as pipelines or electrical cables, using longitudinal and cross sectioning helps in planning their alignment, estimating trench volumes, and identifying potential conflicts with existing infrastructure.
• Land development: When planning residential or commercial developments, longitudinal and cross-sectional surveys provide valuable information for site grading, building placement, and determining drainage patterns.

Benefits

• Accurate data: These techniques allow surveyors to gather precise elevation and terrain data, providing a solid foundation for engineering design and decision-making.
• Efficient design: Longitudinal and cross-sectional surveys facilitate the design of infrastructure elements, enabling engineers to optimize grades, alignments, and earthwork quantities.
• Enhanced visualization: The graphical representation of longitudinal and cross-sectional data helps stakeholders visualize the project’s topography and understand its impact on the construction process.
• Conflict identification: By identifying potential conflicts, such as steep slopes or underground utilities, early in the surveying process, longitudinal and cross sectioning help avoid costly design revisions during the construction phase.

Longitudinal and cross sectioning techniques play a vital role in surveying, providing valuable data for civil engineering projects. The detailed profiles and cross sections derived from these surveys aid in optimizing alignments, grades, and earthwork quantities while minimizing conflicts and ensuring efficient project execution.

What is a photogrammetry software?

Photogrammetry software is a computer program that provides the tools for performing photogrammetric measurements, such as loading photos from your camera and producing accurate measurements, maps, and models from those photos. In drone technology, photogrammetry sensors are typically high-resolution cameras that take pictures from various angles while flying over the area of interest. A 3D point cloud of the terrain or object is then produced by stitching together these images using specialized software. This point cloud can then be further processed to create a full 3D model, allowing anyone to view it from any angle as if they were physically holding it in their hands. The software to process these images can be desktop or cloud-based.

Cloud-Based Photogrammetry Software

Cloud-based photogrammetry software refers to applications that leverage cloud computing resources for processing and storing data related to photogrammetry. Cloud-based survey software makes it easier for companies to create surveys and receive responses quickly, making the entire process cost-effective. Compared to locally based solutions, cloud-based survey software doesn’t require a particular computer as it can be used online using a web browser.

Salient Features of cloud-based photogrammetry Software

• Data Upload: Users can upload their images or datasets to the cloud platform for processing. The software may support various image formats and offer tools for organizing and managing the data.
• Data Processing: The cloud-based software uses powerful computational resources in the cloud to perform photogrammetric processing tasks. These tasks include feature extraction, image matching, triangulation, dense point cloud generation, and mesh reconstruction.
• Automation and Optimization: Cloud-based photogrammetry software often includes automated processes and optimization algorithms to streamline the photogrammetric workflow. These features help improve the accuracy and efficiency of data processing.
• Visualization and Analysis: The software lets users visualize and analyze the photogrammetric results once the processing is complete. This may include viewing 3D models, orthomosaics, digital surface models, and point clouds, measuring distances, area, and volumes, and extracting specific information from the data.
• Collaboration and Sharing: Cloud-based platforms often provide collaboration features, allowing multiple users to access and work on the same datasets simultaneously. They also enable sharing and distribution of processed data through online galleries, sharing links, or embeddable viewers.

Pros

• Cost-effective: Cloud-based photogrammetry software follows a subscription-based pricing model, allowing users to pay for what they need when needed. This eliminates the need for significant upfront investments and provides more predictable costs.
• Time-saving: Cloud platform reduces risk and automates manual tasks.
• Accessibility: Cloud-based software allows users to access their photogrammetry tools and projects from anywhere with an internet connection. This flexibility benefits remote collaboration, fieldwork, or accessing projects on different devices.
• High accuracy and detail: Cloud Photogrammetry software can produce highly accurate and detailed 3D models and point clouds with high-resolution images and appropriate processing techniques.
• Flexibility and scalability: Photogrammetry software offers flexibility regarding the type of imagery it can process, such as aerial or ground-based photos, and can handle large datasets. Cloud-based solutions often offer scalable processing power and storage. You can easily handle large datasets and complex projects without investing in expensive hardware upgrades.
• Storage and Data Security: The data can be accessed anytime, anywhere since the data is stored in the cloud. There is no risk of losing the data.
• Collaboration: Cloud-based platforms enable real-time collaboration and data sharing among team members or stakeholders. Multiple users can simultaneously work on the same project, facilitating efficient teamwork and feedback exchange.
• Automatic Updates: Cloud-based software providers can release updates and improvements seamlessly without requiring users to install them manually. This ensures users can access the latest features and enhancements without additional effort.
• Integration: All outputs can be downloaded and exported to third-party CAD and GIS software for further analysis.

Cons

• Internet Dependency: Cloud-based software heavily relies on internet connectivity. If you have a slow or unreliable internet connection, it can hinder your ability to upload and process large image datasets efficiently.
• Data Security: Storing data in the cloud may raise concerns about data security and privacy. It’s essential to ensure that the chosen cloud provider has robust security measures and complies with industry standards and regulations.
• Data Transfer and Upload Times: Uploading large image datasets to the cloud can be time-consuming, particularly if you have limited bandwidth. This process may introduce delays before you can start processing your photogrammetry projects.
• Limited Offline Functionality: Cloud-based software generally requires an internet connection to access and use the tools. If you work in an area with limited connectivity, you may be unable to work on your projects or access your data.
• Dependency on Service Provider: When using cloud-based software, you depend on the service provider’s availability and performance. Any downtime or technical issues on their end can impact your ability to work on your projects.

Inertial Measurement Units (IMU)

An Inertial Measurement Unit (IMU) is an electronic device that measures acceleration and rotation that can be used to calculate position and velocity. IMUs are the main component of the inertial navigation systems commonly used in aircraft, unmanned aerial vehicles (UAVs) and other unmanned systems, as well as missiles and even satellites.

Accelerometer

Accelerometers are used to determine the position and orientation of the drone during flight. Accelerometer is used to provide the acceleration force the drone is subjected to in all three axes, X, Y, and Z. It also determines the tilt angle of the drone in a stationary position. If the drone is static in a horizontal position, its X and Y axis will give 0g output, whereas the Z axis will give 1g output. 1g is the gravity that is experienced by every object on Earth. If the drone rotates by 90deg on the X axis, then X and Z will give 0g, and the Y axis will start giving 1g. During the tilt, X, Y, and Z will provide an output between 0 and 1g.

Gyroscope

Gyroscopes are versatile tool for measuring and maintaining orientation. This is especially important for drones that are used for aerial photography, as they need to remain stable and level to capture the best images. Gyroscopes are frequently combined with accelerometers, which measure linear acceleration. These two components work together to give the drone the information it needs to determine its position and orientation in three-dimensional space.

The use of gyroscope technology aids in the maintenance of a stable hover. The gyroscope detects any wayward drifting or wobbling by the drone when there is no input from the pilot. This data is then sent to a controller instructing the drone’s motors to counteract unwanted movements.

Gyroscope sensor detects angular velocity in three axes. So it can detect the angle change rate Pitch, Roll, and Yaw.

Gyroscopes also ensure that drones rotate at the exact angle user controls expect.

Magnetometer

A magnetometer measures a magnetic field’s intensity and direction. It gives data on the magnetic field in three X, Y, and Z. This helps the drone to determine the magnetic North and change its course accordingly. Apart from direction sensing, magnetic sensors can also detect surrounding magnetism and ferro-metals, such as electricity poles, wires, vehicles, other drones, etc., to help avoid an accident.

Barometer

GPS Sensor

GPS technology has been critical in enabling drones to fly autonomous missions. It determines which way the aircraft should move by comparing the actual position of the drone with its targeted position and instructs the drone motors with the appropriate commands.

A drone is outfitted with a GPS receiver that can receive signals from multiple GPS satellites. Depending on the location of the satellite source, the time it takes for the drone’s GPS module to receive the signal will vary. The drone’s location can be determined by triangulating the relative position of the drone from the different GPS satellites. The precision of the location will be determined by the strength of the signal received by the drone’s GPS module and the number of satellites within its range.

The previous SOP only mentioned submitting the Digital Elevation Model (3D), i.e., Digital Surface Model and Digital Terrain Model. In the new updated SOP, it has been made clear that the Digital Elevation Model (3D), i.e., Digital Surface Model and Digital Terrain Model, should include the 100m buffer zone. The spatial resolution of the image has also been defined, which should be less than or equal to 15cm in UTM Projected Coordinate System and in Geotiff format.

Compared with the Previous SOP, the new updated SOP clearly defines the GCPs that must be submitted to IBM. The new updated SOP has divided the GCPs that must be submitted to IBM into three files.

1.                 The total GCPs DGPS Survey data, including permanent GCPs, must be submitted to IBM in GCS                      WGS-84 datum and UTM Projected Coordinate System in Excel Format.
2.                 The Permanent GCP data needs to be submitted to IBM both in GCS WGS-84 datum, and UTM                          Projected Coordinate System in Excel Format.
3.                 The plan of GCPs needs to be submitted to IBM in UTM Projected Coordinate System in shapefile                      format.

• In the new SOP, submitting the RMSE report in .txt, .doc, and .pdf format has been mandatory. Earlier, the RMSE report needed to be submitted only in .txt and .doc format.
• There are also major updates in the map of the mining lease area. More features have been added to the map that needs to be marked in the map before submitting it to IBM. The updated features are listed below.

1. 1. ML Boundary
2. 2. Topsoil stack
3. 3. Infrastructure
4. 4. Roads
5. 5. Railways
6. 6. Tailing Pond
7. 7. Effluent Treatment Plant
8. 8. Mineral Separation Plant
9. 9. Township Area
10. 10. Others to specify (Green Belt area)

In the previous SOP, the Boundary Pillar coordinates must be submitted in the shapefile and Excel format in Geographic Coordinate System and Projected Coordinate System. In the new updated SOP, the boundary pillar coordinates must be submitted in Excel format in GCS and UTM. Also, a plan of the leased boundary pillar coordinates also needs to be submitted in UTM and GCS in WGS 84 datum. Although here, two separate shapefiles for GCS and UTM must be submitted.

Finally, As per the previous SOP, the Drone Survey Log Sheet needed to be submitted only in the .doc format, while in the new updated SOP, it has been made clear that the drone survey log sheet needs to be submitted both in .doc and pdf format.

10. Data Output and Formats

The outputs that need to be submitted are discussed below:

11. Submission of Data to IBM

The processed output data of the drone survey shall be submitted in soft copy only in storage media (i.e., external hard disk) on or before 1st July every year along with the Output data submission form at the following addresses.

1. The Chief Mining Geologist, Indian Bureau of Mines, GM&MM Cell, 1st Floor, A- Block Indira Bhavan, Civil Lines, Nagpur- 440001, Maharashtra
2. Respective Regional Offices Indian Bureau of Mines

What is an SOP?

SOP stands for Standard Operating Procedure. A standard operating procedure is a document that contains step-by-step instructions and guidelines for employees to follow when performing a technical, repetitive process within an organization. SOPs are employed by a number of organizations to guarantee that tasks are carried out consistently, effectively, and with the least chance of error or omission.

1. Drone Agency Registration and Permissions

There is no need to register with IBM for drone survey in mines. Drone Agencies or the lessee can conduct the survey while following all the applicable rules, regulations and guidelines notified by DGCA. Check the Airspace map from the Digital Sky website. The drone airspace map is an interactive map of India that demarcates the red, yellow and green zones across the country.

Green zones are the unrestricted zones where drones can be operated without any permission

Yellow zones are controlled zones and the drone can only be operated after a permission from DGCA.

2. Drone Specification

Drones used for the survey should follow DGCA guidelines and should possess mandatory safety features as notified by DGCA from time to time.

3. Sensor/Camera Specification and output data resolution

5. Survey Area

The survey should cover the entire mining lease area capturing all mining, allied activities and 100m beyond periphery of the mine lease boundary to monitor the environmental impact and ascertaining any excavation therein. The flight path plan and the numbers of flights taken to cover the entire area shall be provided to IBM along with the output data. For leases having common mine boundary, the survey may be limited up to the lease boundary for the sides, the lease shares common boundary with another lease.

7. Drone Survey Time

It is advised to fly the drone in better conditions when the sky is clear and the sun is overhead to minimize the shadows in photographs. Do not fly the drone when it is rainy or windy.

Mission

The primary mission of Indian Bureau of Mines is to promote systematic and scientific development of mineral resources of the country (both onshore and offshore), through regulatory inspections of the mines, approval of mining plans and environment management plans to ensure minimal adverse impact on environment.

It has been proposed to use a combination of digital aerial (Drone and satellite) images to monitor mining activities in the country. In mining, drones have various applications like mine surveying, inventory management, stockpile evaluation etc.

Ministry of Mines has incorporated Rule 34A in the Mineral Conservation and Development Rules 2017 for submission of digital aerial images of mining lease areas to Indian Bureau of Mines

What is MCDR?

The MCDR have been framed under section 18 of the Mines and Minerals (Development and Regulation) Act, 1957 [MMDR Act] to provide rules regarding conservation of minerals, systematic and scientific mining, development of the mineral in the country and for the protection of environment.

KML Boundary Extension

As per IBM, the drone survey should be conducted upto 100 metres outside the lease boundary. If you are confused on how to increase the lease boundary, you can extend your original KML boundary using the KML Boundary Extension free tool from this website.

Enter the website and upload your orginal KML boundary. At the top right corner input the distance in meter upto which you need to extend the boundary and click submit.