Remote Sensing Technology for Map-making
During the US Civil War, messenger pigeons and unmanned balloons with cameras attached to them used to be sent over to the enemy territory. That was one of the first documented uses of remote sensing. Even before the satellites were developed in the late 20th century as a part of remote sensing activity, the two World Wars had witnessed government-sponsored air photography missions for military surveillance.
Remote sensing is the art and science of measuring any region on earth using sensors that collect data in the form of images. These images are then used as the input data for map making.
Remote sensing technology – which uses devices (sensors or cameras) on the ground or on ships, aircraft, and satellites – has become a useful tool for geographers as it helps them study a region without being physically present there. Remote sensing technology not only helps geologists in mapping large and remote areas and identifying rock types, but also aids ecologists in studying vegetation types in certain areas.
Map-making with remote sensing data calls for using geometric and radiometric processing methods adapted to the nature of the data. This helps in acquiring the best cartographic and topographic information.
Mobile Mapping Technologies
The idea of collecting geospatial data from a mobile vehicle has not been hatched very recently. Mobile mapping, as an activity, has undergone layered developments ever since photo-logging system emerged in the 70s. This system was put into use by transportation departments to monitor pavement performance and encroachments. The monitoring was done with the help of film cameras that used to capture photos through the windshield of a vehicle. With the advent of the video imaging technologies, photo-logging was replaced by GPS-based video-logging. The task of georeferencing the collected video images in respect to a global coordinate system became easier.
With the evolution of mobile mapping systems in the last decade of 20th century, the 3D mapping capabilities came into the picture. This development is attributed to two research groups in North America. In mobile mapping systems, more than one camera is mounted on a mobile platform for stereo imaging and 3D measurements. Direct georeferencing of digital image sequences was made possible by the multi-sensor navigation and positioning techniques.
Multi-platform and multi-sensor integrated mapping technology has enabled swift collection of geospatial data. Hence, it is useful in emergency response planning by offering accurate assessment of conditions on the ground. In fact, the unbridled growth of telecommunication networks and portable sensors made mobile mapping more pervasive. Internet giants such as Google use aerial photographs and satellite images to develop online mapping systems. Moreover, internet users are increasingly utilizing geo-spatial information.
Applications of Mobile Mapping Systems
Mapping of roads and railways is perhaps the prime operating area of mobile mapping systems. The core focus is on providing near-accurate maps of road features, which could be used by transportation departments for road assessment management, transportation planning and engineering. Mobile mapping helps its beneficiaries through its end products like digital images of roads, information on road related feature, and positions of bridges, buildings, manholes and traffic signs.
This mapping system is put into use for utility mapping. The maps, which are derived from leveraging mobile mapping technologies, are referred by telecommunication companies to plan and maintain inventory of transformers, power lines, telephone lines, street light poles, etc. Moreover, mobile mapping system proves handy in establishing emergency response databases.
Transforming Role of Drones in Creating Maps
Back in 2013, when the U.S. military felt the need to identify mines in terror-prone zones of Afghanistan, an aerial-imagery specialist built a plane-based system to map the region. It was an expensive project. However, that experience is widely believed to have sparked the idea of mapping by drone. Conventional aircraft made way for unmanned aerial vehicles (UAVs) to carry out mapping tasks.
Maps produced from UAV images are now transforming the way the map making activity is looked at. From cemetery management to mining and anti-poaching efforts to assessment of disaster-prone zones, drone technology is making it easier for cartographers, surveyors and government agencies across the world.
While almost anyone can buy a drone and get into aerial photography, the real challenge is to put the images together and create a map. This is where the importance of an image-processing tool is felt. Similarly, Patrick Meier, Director of Social Innovation at Qatar Computing Research Institute, has realized the importance of effective drone-mapping software. His team is now also exploring the possibility of using artificial-intelligence algorithms to automate the process and enhance the efficiency component in processing a large number of image samples.
From conservation experts to geologists, every stakeholder is now preferring drone mapping to the ones dependent on satellite images for terrain mapping and surveying. The reason is a no-brainer. Drones can get them higher resolution images at a faster pace and moreover, they are far more economical.
Advantages of GIS vs CAD for Making Maps
Cartographers often find themselves in a fix when it comes to choosing between GIS and CAD-based digital mapping systems. It is important to understand that GIS models the world as it is, while CAD models artifacts that are yet to be produced. As a technology that automates, organizes, and drafts map data, CAD allows a user to create a very accurate drawing, be it a map or a site plan. For map making, a cartographer would prefer to create the line work in CAD. It enables drawing by the use of coordinates or distances or angles.
However, it is to be borne in mind that CAD originated with a purpose of designing buildings and machines. While CAD can be used to make maps, it was never designed for this. Those who draw maps with CAD don't go beyond line drawing. The GIS technology fills gap left by CAD systems. It brings in value by attaching data to the points, lines, and polygons used in the map. This makes GIS the ideal tool for analyzing and visualizing data through a map.
GIS is known for offering flexibility as it can be used as an automated drafting tool. Rather than just storing and regenerating graphics, GIS also involves plotting of all displays according to information maintained in a database format. This technology is capable of managing large collections of spatial information. It is also focused on the manipulation, analysis, and display of spatial data. While GIS makes use of topology (calculate and analyze spatial functions) to identify relationships among various spatial objects, CAD does not inherently include topology.
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Last Updated : June 12, 2015
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