Products and Services

SMG will be utilising 4 technologies, namely airborne Lidar, hyperspectral imaging, satellite imaging and Geographic Information Systems.

Lidar (Light detection and ranging) is a service offering that allows aerial mapping of earth surface features. Using its state of the art systems, up to 200 000 accurate survey points can be captured per second, to derive 3D terrain information. A digital camera allows for the simultaneous acquisition of aerial photography of up to 5cm resolution. It provides significant time and cost savings.

For applications requiring less detail, distribution agreements with world leading satellite operators, allow SMG to provide end-users with rapid turnaround access of up to 50cm resolution satellite imagery and 5m digital elevation models of any location in the world.

SMG offers airborne hyperspectral imaging technology to its client base and is the only local company able to offer this service. Hyperspectral imagery is a technology which can simultaneously capture up to 500 images in different parts of the electromagnetic spectrum. Since plants, soils, minerals and pollutants have unique spectral properties; these can be mapped from the imagery.

With its extensive digital data archive, SMG is able to provide GIS services for government and commercial sectors.

Lidar for Mining

Surveying potential and existing mining landscapes and creating accurate maps can be somewhat troublesome. Mines are often situated in remote locations and surveying the landscape via traditional methods becomes vertually impossible. Lidar uses laser distance measuring technology to perform topographic mapping over many different landscapes.

The team from Southern Mapping Company (SMC) has surveyed mines and exploration areas in many countries across the globe. The survey results are used for a number of applications throughout the life cycle of a mine:

• Audit surveys

• As build surveys

• Infrastructure design

• Mine expansion planning

• Stockpile and pit volumes

• Environmental rehabilitation and monitoring

• Surveys in dangerous or inaccessible places

• Slimes dams design, survey, monitoring and rehabilitation

• High accuracy DTM for enhanced geophysical analysis (during prefeasibility)

Why Lidar?

Lidar uses laser distance measuring technology to perform topographic mapping. When combined with a digital camera, a complete high speed mapping system is created.

The Lidar unit is capable of measuring up to 100 000 pulses per second, which results in a shot density of 1.7 points/m² at a typical flying height of 1000m above ground level. The accuracy of these strikes is typically 10cm. The digital camera provides high resolution and full colour imagery. For example, an image resolution of 14cm is achieved from a flying height of 1000m.

Exploration and planning surveys

To properly interpret the geophysical exploration surveys, an accurate terrain model is required. A full colour, high resolution image will help to understand the exploration data. If the site is worth developing, then the Digital Terrain Model (DTM) and imagery will be used for mine planning, which will include infrastructure location and design, the positioning of stockpiles and waste dumps.

Volume surveys

During the life cycle of the mine, it is necessary to regularly survey the mine to provide pit and stockpile volumes. In many cases it is not possible to accurately compute volumes from ground surveys with a conventional photogrammetric device due to several access difficulties such as high walls, the nature of a stock pile and the muddy consistency of slimes dams. The density of points obtained during a Lidar survey means that any access difficulties are removed.

Infrastructure updates

A mine is a constantly changing environment as pits and stockpiles grow and roads, buildings, pipes, conveyors and other infrastructure are being put in place. These changes need to be recorded on the mine plans. An up to date orthophoto, combined with the Lidar elevation data, provides the means to identify changes and update the plans.

Environmental management and rehabilitation

Impact on the mining environment is often unavoidable. A vital component of mine operations is the management and rehabilitation of such an environment, particularly with regard to soil erosion and water drainage. The Lidar survey provides the necessary information about the topography of the landscape to enable proper planning for the rehabilitation and environmental management of the mining area.

Airborne Lidar Mapping

About Southern Mapping Company (SMC)

Southern Mapping Company (SMC) provides topographic surveying and mapping for a variety of industries and sectors. These include civil engineering and infrastructure development, mineral explorations and mine management, environmental planning and rehabilitation, and urban and agricultural planning. The company combines aerial Lidar and Hyperspectral technologies to produce highly accurate surveys and maps. SMC specializes in mining surveys for exploration and rehabilitation, linear route surveying such as power lines, roads, pipelines, railways and all other forms of infrastructure, whether new or existing. The Lidar sensor enables highly accurate and dense topographic data acquisition in the most efficient means possible and over any terrain. The accuracy of surveys varies according to client requirements, with specifications ranging from 2m contours all the way down to 25cm contours. Image resolution similarly ranges from 50cm to 5cm.

Lidar technology

Lidar uses laser distance measuring technology to perform topographic mapping. When combined with a digital camera, a complete high speed mapping system is created. The Lidar unit is capable of measuring up to 100 000 pulses per second, which results in a shot density of 1.7 points/m² at a typical flying height of 1000m above ground level. The accuracy of these strikes is typically 10cm. The digital camera provides high resolution and full colour imagery. For example, an image resolution of 14cm is achieved from a 1000m flying height.

Advantages of Lidar

Lidar technology provides numerous advantages compared to conventional surveying and mapping technologies such as total stations, GPS and photogrammetry. Advantages include: Vegetation penetration: Lidar has a very narrow beam that is emitted from the aircraft. This beam penetrates dense foliage to reflect off the ground and return to the aircraft. This provides accurate ground elevation readings beneath the tree canopy.

Accuracy: Due to the sheer density of laser points, as well as their inherent accuracy, a terrain model of extremely high accuracy can be delivered.

Ground survey: Minimal ground control is required due to the accurate measuring equipment used in the aircraft.

Digital workflow: Both the Lidar and the digital camera deliver their raw data to computer discs in the aircraft. This data is then delivered to the processors. Within hours, documentation of the days surveying is complete. Within a few weeks, the entire project will have been processed, checked and packaged for delivery.

Products

SMC produces two main outputs.

The Orthoimage

This is used as a layer in a Computer Aided Drafting (CAD) or Geographic Information System (GIS). In a built environment it shows the size and location of man-made objects such as roads, buildings, pipe and power lines, as well as excavations and stockpiles. In other situations it highlights the position of different vegetation types, shows degraded or eroded areas, and provides locations and extents of water bodies.

The Terrain Model

This can be delivered as simple ground and non-ground sets of files. Alternatively, the data above the ground can be further classified to extract information such as power lines, buildings and trees.

This data is used for a multitude of purposes and include the following:

• Disaster planning
• GIS data capturing
• Telecoms planning
• Expansion planning
• Optimization of existing power lines
• Calculation of pit and stockpile volumes
• Design of new roads, power lines, pipelines
• Biomass volumes to determine the extent of vegetation
• Dam site selection, full level and volume determination

Lidar for Power Supply

Access to electricity is vital to sustain a decent quality of life. Companies are under pressure to deliver power to end users in greater quantities and at a greater speed than ever before. At the same time, it is becoming more difficult to find sites for power generation and routes for transmission lines. This increases due to environmental and stakeholder pressures. Lidar is the ideal technology to assist in relieving some of these pressures as it saves time and allows for easy access to a proposed site.

The team from Southern Mapping Company (SMC) has surveyed power generation sites and power line routes worldwide. The results are used for a variety of applications and include:

• Site selection, whether the source is hydro, coal, or nuclear
• Infrastructure design on the final site, from supply of raw material to delivery of power
• Life cycle surveys for on-going design and maintenance
• Selection of the optimal transmission line corridor
• Profile survey of the final route
• Ampacity survey of an existing line for optimisation

Why Lidar?

Lidar uses laser distance measuring technology to perform topographic mapping. When combined with a digital camera, a complete high speed mapping system is created. The Lidar unit is capable of measuring up to 100 000 pulses per second. This results in a shot density of 2 points per m² - a typical flying height of 800m above ground level. The accuracy of these strikes is typically 10cm. The digital camera provides high resolution and full colour imagery.

Once a site has been short listed, an accurate survey is necessary for the design of the plant, access routes, conveyer belt alignments, waste dumps, HV yard, as well as exit routes for power lines. A Lidar survey will do this quickly and accurately, without a need for ground access to the site.

A swathe width of 250m on either side of a proposed power line centre line is covered during the flight, which means that the route can be surveyed before final route selection is made, and the survey information can be used for this final alignment. In addition, the Lidar is able to penetrate thick vegetation, therefore no bush clearing needs to be done prior to the flight. The route can be surveyed before the Environmental Impact Assessment (EIA) process is complete as no ground clearing is necessary.

Existing lines need on-going maintenance to ensure trouble free operation. A regular Lidar survey will provide accurate information about the location and size of vegetation that may threaten the proposed operation. Heights of trees and bush areas, as well as their distance from the conductors, can be accurately measured, allowing for the removal of obstructing vegetation.

Many existing lines have been designed with excessive safety margins and have an untapped carrying capacity. Lidar is the only echnology that is able to rapidly survey an existing line and capture ground and can then be entered into design software to determine unnecessary vegetation clearance and optimise power flow.

Hyperspectral applications for the agriculture sectors

Southern Mapping Company has invested in hyperspectral imaging equipment that is set to revolutionize the mapping industry in South Africa. The current Lidar equipment used at Southern Mapping is able to produce a three-dimensional digital terrain model on which the images are superimposed. With the addition of the hyperspectral remote sensing technology, the company is able to identify individual species of plants and trees, noxious gasses and aerosols, minerals and soil types allowing us to broaden our services into the public and private agricultural, forestry, water and air quality and mining sectors.

Technological advancements in sensor technology over recent decades have resulted in hyperspectral sensor systems. Hyperspectral systems now make it possible to collect and analyze hundreds of spectral bands across the electromagnetic spectrum, providing detailed spectral data previously not possible through multi-spectral systems.

Hyperspectral signatures

Each object on the surface of the earth (mineral, plant, soil or gas) is identifiable by the unique manner in which it reflects energy across the electromagnetic spectrum. This unique reflectance constitutes a 'fingerprint', represented by its spectral response or spectral signature across the electromagnetic spectrum. By processing the hyperspectral data with advanced image processing software, it is possible to automatically identify the location of features that display specific spectral signatures.

Hyperspectral Technologies for Agriculture – Precision Farming

Precision farming is an agricultural concept that seeks to optimize agricultural inputs on the basis of 'in-field variability', i.e. that varying nature of soil content, land carrying capacity etc.

The accurate determination of in-field variability allows for the effective implementation of precision farming techniques, such as:

• Early detection of disease
• Soils characterization and inventory
• Harvest estimation
• Reasoned and supervised treatment of plots

The precision management of farming activity increases efficiency and output, while Reducing environmental impacts. The availability of hyperspectral sensor systems allows precision farming experts the opportunity to choose solutions-oriented products derived from hyperspectral data.

Effective and timely disease management is critical in maintaining a competitive advantage in the agricultural sector. Like many crops, sugarcane is susceptible to a variety of pathogens that can cause serious damage to crop yield. Curative measures to minimizing the impact of crop disease range from identifying the location and extent of stressed crops, to the application of chemicals for disease control.

Application Area – Soil Characterization & Inventory

Up-to-date and accurate information on soil properties is important for precision farming and environmental management. While conventional soil sampling procedures are labour-intensive, time-consuming and expensive, hyperspectral remote sensing techniques provide a rapid and efficient tool for mapping soil properties.

Application Area – Harvest Estimation

Crop yield estimation is becoming increasingly important on the back of ever growing population numbers, both nationally and internationally. Consequently, there is a growing need for micro-level planning and particularly the demand for crop insurance which increases the need for field level yield statistics.

There are two methods for yield estimation:

1. Conventional methods are often complicated, costly, time consuming and they cannot be run in large scale. It is therefore necessary to seek and employ cheaper/faster methods for crop yield estimation.
2. Remote sensing data, and in particular hyperspectral reflectance data, has the potential and the capacity to provide spatial information of features and phenomena on any part of the earth's surface on an almost real-time basis.

Hyperspectral remote sensing has been proven to be a very effective tool for the estimation of crop variables such as LAI, pigment and water content; therefore it is reasonable to expect that data from hyperspectral remote sensing can show great potential for monitoring crop biomass accumulation, either directly or indirectly through other variables.

Application Area – Reasoned Plot Treatment

Large amounts of organic and inorganic nutrients are used in modern agriculture to maximize crop yield. Unfortunately, excessive nutrient applications negatively affect environmental quality and human health. Water bodies that become too rich in mineral nutrients typically present in commercial fertilizer, experience 'eutrophication', resulting in 'dead-zones' where low oxygen levels in the water promote algae growth and the decline of marine life. Precision farming seeks to minimize these impacts through the efficient management of fertilizer use.

Implications for South African Agriculture

South African agriculture is a well developed sector of the national economy, contributing approximately 8% to the country's total exports. The diversity of South Africa's climatic regions – tropical, subtropical and desert, offers the potential for a wide variety of agricultural products.

South Africa's largest export groups include wine, citrus, sugar, grapes, maize, fruit juice, wool and deciduous fruits. Agricultural activities range from intensive crop production and mixed farming in winter rainfall and high summer rainfall areas to cattle ranching in the bushveld and sheep farming in the arid regions. Maize is most widely grown, followed by wheat, oats, sugar cane and sunflowers. There is potential for the application of the various hyperspectral reflectance data precision farming techniques outlined in this article for each of these crops.

It is important to note that while 13% of South Africa's land can be used for crop production, only 22% of this is high-potential arable land. The most important limiting factor is the availability of water. Rainfall is distributed unevenly across the country, with some areas prone to drought. Almost 50% of South Africa's water is used for agriculture, with about 1.3-million hectares under irrigation.

Under these conditions, it is becoming increasingly important that the South African agricultural sector take advantage of hyperspectral reflectance data techniques in pursuit of precision farming practices. As demand for agricultural produce increases so to must supply to maintain food security both domestically and internationally. In the absence of new agricultural land resources upon which to expand commercial agricultural operations, yield on existing farms must be optimized.

Hyperspectral applications for the mining sector

Southern Mapping Company has invested in hyperspectral imaging equipment that is set to revolutionize the mapping industry in South Africa. The current Lidar equipment used at Southern Mapping is able to produce a three-dimensional digital terrain model on which the images are superimposed. With the addition of the hyperspectral remote sensing technology, the company is able to identify individual species of plants and trees, noxious gasses and aerosols, minerals and soil types allowing us to broaden our services into the public and private agricultural, forestry, water and air quality and mining sectors.

Technological advancements in sensor technology over recent decades have resulted in hyperspectral sensor systems. Hyperspectral systems now make it possible to collect and analyze hundreds of spectral bands across the electromagnetic spectrum, providing detailed spectral data previously not possible through multi-spectral systems.

Hyperspectral signatures

Each object on the surface of the earth (mineral, plant, soil or gas) is identifiable by the unique manner in which it reflects energy across the electromagnetic spectrum. This unique reflectance constitutes a 'fingerprint', represented by its spectral response or spectral signature across the electromagnetic spectrum. By processing the hyperspectral data with advanced image processing software, it is possible to automatically identify the location of features that display specific spectral signatures.

Hyperspectral technologies for mining

The huge volumes of multidimensional data collected by hyperspectral systems make a wide diversity of mining applications possible, in particular:

• Mineral deposit detection
• Identification & monitoring of mining operations
• Identification & monitoring of tailings, overburden piles
• Mine pollution monitoring

Mineral Deposit Detection

Mineral deposits, and their related indicator materials, have a unique spectral signature based on their relative compositions. Hyperspectral reflectance data may be used to identify concentrations of target mineral deposits over large areas. This is particularly useful in regions where difficult terrain hampers manual site testing.

Mining Operations

Hyperspectral imagery allows for detailed spatial and spectral analysis of mining operations in remote locations. The extent of mining operations, and how they change over time can be identified and monitored on a regular basis through the imagery.

Changes in the surface chemical composition of mine tailings (dumps) and mining pits can be identified, providing useful information on the changing chemistry of surface mining conditions over the life cycle of the mine. High resolution imagery provides detailed spatial information that may be used to optimize plant, human resource and material processing logistics within the mining complex.

Tailings / Overburden Piles

After the crushing and grinding (milling) processes, some of the metal-containing minerals are left behind as small tailings particles. Mine tailings are often rich in metal contaminants, suchas arsenic, lead and cadmium. As tailings erode due to wind and water exposure, fine particles and their associated contaminants are dispersed as dust particles great distances from their point of origin.

Hyperspectral reflectance data has made it possible to accurately identify the spatial distribution of metal contaminants among mine tailings. Erosion patterns, and resulting chemistry changes may also be monitored in support of pollution management and tailing rejuvenation projects. Hyperspectral imagery allows the mining industry and environmental managers to obtain spatially comprehensive, accurate data for mapping and monitoring environmental effects.

Mine Pollution

Mining operations pose significant problems in terms of land, water and air pollution. The effective mitigation and management is important to minimize the impacts of mine pollution on people and the environment. Of particular concern is the phenomenon of acid mine drainage (AMD). AMD refers to water with high concentrations of sulfuric acid draining out of surface or subsurface mines. AMD poses a threat to water quality in terms of salinity, levels of sulphates and heavy metals. Recent research has identified AMD as the single most significant threat to the South African environment, with concerns over the progressive contamination of ground water aquifers in the Witwatersrand Basin.

Minerals that precipitate from acid waters draining from base metal mine workings are useful targets for remote sensing since they indicate the source, extent and conditions of environmental pollution. Hyperspectral reflectance data can be used to identify the known spectral features of contaminant materials present in AMD.