Photogrammetry vs. LiDAR

Introduction

Photogrammetry is specifically a method to carry out surveys and prepare maps using photographs. It is an art, science, and technology of gathering reliable data concerning any entity. This method involves a method of record-keeping, measuring, and evaluating terrestrial and aerial images. Photogrammetry, in other words, is the methodology to make measurements with the help of photographs.

Photogrammetry is a combination of three different words; Photo – light, Gram – drawing, and Metry – measurement. So, photogrammetry means merely light, pictures and measurements. The technology proves to be useful in creating maps.  The user designs maps with the help of photographs clicked with the use of drone cameras.

Types of Photogrammetry

Photogrammetry is of two kinds:

• Terrestrial Photogrammetry
• Aerial Photogrammetry

1. Terrestrial Photogrammetry

Terrestrial photogrammetry is the one that consists of performing measurements by taking photographs from some specified positions on the earth’s surface. This category of photogrammetry uses photos taken with regular camera and theodolite.

2. Aerial Photogrammetry

Photogrammetry uses drone cameras or cameras mounted on aircraft. Aerial photogrammetry not only has higher precision but also has higher accuracy than the terrestrial photogrammetry.

LiDAR – Light Detection and Ranging

Lidar (Light Detection and Ranging) is the method of remote sensing which uses light pulses in the form of a laser, and the receiver senses the reflected pulses. To take the measurement of the time required by the pulse to return to the receiver, the distance calculation takes place. Once the light pulses are merged with other essential data gathered with the use of aircraft, the user correspondingly gets the properties regarding its surface, together with some three-dimensional data regarding the earth’s shape.

A LiDAR mod mounted on the planes comprise mainly of a laser emitting device, a scanner, and one GPS receiver. The aircraft (airplane or helicopter) installed with the mod transmits the pulses to the ground.

LiDAR is of two types, viz. Topographic LiDAR and Bathymetric LiDAR.

1. Topographic LiDAR

This type of LiDAR implements aircraft with a device that continuously transmits infrared signals for mapping the land. In this, an airplane or a helicopter floats in the air over the ground to be mapped, and furthermore, it continuously emits the infrared pulses to the field.

2. Bathymetric LiDAR

Bathymetric LiDAR is the one which uses green light that penetrates into the water bodies and determines the elevations of seabed and riverbeds. This LiDAR system is suitable for creating shoreline maps and prepare the elevation models in digital forms.

LiDAR has rather proven to be delivering useful grades of accurate data. On the other hand, the technology is quite flexible for the scientists.

Summary

When it comes to comparison between two different techniques for the same thing, in particular, accuracy is the primary thing that a user might consider before using any one of them. LiDAR, of course, gives you the best accuracy than photogrammetry. However, both the technologies are widely used as per the users’ feasibility. Specifically, they are ideal for carrying out different tasks.

To sum up, photogrammetry is easier than LiDAR, but LiDAR is ultimately the best one out of the two.

Do share your views in the comment box.

Source: https://blog.nibt.education/2018/03/photogrammetry-vs-lidar/

Aerial Photogrammetry vs. Terrestrial Photogrammetry – Understand the Contrast

Photogrammetry is the science and technique that blends photography and geometry. The principle is straightforward, yet it has a significant impact on contemporary architectural establishments.

What is the procedure of photogrammetry, you can check here–

We all know that photography generates 2D illustrations. The photogrammetry system produces 3D estimations of the object and surface from the 2D image/photograph.

If you read our previous blogs on photogrammetry, then you will know that Aerial and Terrestrial are two major varieties of photogrammetry.

Let’s understand each one by one-

Aerial photogrammetry

A machine, especially an aircraft (purposefully designed plane) or a drone, i.e. Unmanned Aerial Vehicle (UAV) has the cameras attached. Therefore, it can capture photos from the higher surface. The larger the number of images, the higher is the accuracy of the statistics. It further helps in comparison of the quality.

The planes fly over the planned area with particular landmarks which they have to capture. The speed of the aircraft regulates the camera’s catching speed. Also, they know the height of the plane from the land surface. The photographed surface area’s base contour/boundary is drawn using Stereo Plotters.

Terrestrial photogrammetry

The word Terrestrial means relating to Earth. Therefore it explains that why the camera is in the stationary position in this kind of photogrammetry. The camera’s position is elevated, and the tilt angle, the focal length of the lens is adjusted.

Read More on Why Aerial Photogrammetry Differs from the Terrestrial One.

The main difference is between the working and methodologies, even though both are the branches of the photogrammetry.

Therefore, the outputs generated are very varied from each other.

Apprehend the following points to notice the distinction-

• The technical requirements of the Aerial photogrammetry are very high-end; the specially designed planes or drones are just the initials.
• Although there is a much lesser investment in Terrestrial photogrammetry, there is the requirement of high technical skills for operating the tools.
• To map a large surface area of the land, we can use Aerial photogrammetry. But the knowledge of longitudes and latitudes with their calculations are essential in photogrammetry operation.
• When there is a need for designers and planners to manage and plan bridges, transportation network, pipeline networks, etc. then Terrestrial photogrammetry is preferred. The adjustments of the camera’s axis as per the surface area matter a lot.
• The environmental projects which trace the changes of glaciers, volcanoes, earthquakes, etc., use terrestrial photogrammetry methods.
• The fixed location of the camera creates such kind of data sets to work upon further.
• There are various benefits of aerial photogrammetry in the security field as well. Archaeology also gets numerous advantages through aerial photogrammetry as you can see a big chunk of the area at once.
• Terrestrial photogrammetry is preferable for movement-related and comparatively smaller land masses, unlike the aerial one.
• The arena where both the fields play an active role is Urban Planning! That’s obvious as with the help of aerial photogrammetry, designers and planners generate an accurate perspective plan of the site or location. An aerial view gives a bright idea of all around the neighborhood, and so it helps in further assessment.
• Terrestrial photogrammetry, unlike aerial, creates visuals showing interrelation between civil constructions, safety issues, disaster management and various other problems. Thus, it helps in knowing the creation, prevention, and demolition of any civilization.

Final Derivation

Thus, it’s evident that by using both sorts of photogrammetry, we can generate most efficient and disaster-prone constructions/infrastructures.

So these were the fundamental differences between aerial and terrestrial photogrammetry. Have you had a clear insight?

Do write your views in the comments.

Source: https://blog.nibt.education/2018/03/difference-between-aerial-and-terrestrial-photogrammetry/

Why Choose Photogrammetry: A Summary for Everyone

Basic Definition of Photogrammetry

The basic definition of photogrammetry is the art, science, and technology of gathering reliable information regarding any physical object and the complete environment.  This technique involves a process of record-keeping, measuring, and evaluating terrestrial and aerial photographs.

Break-down of the term

In a sense, the breakdown of the term photogrammetry is in three parts: ‘photo’ – meaning ‘picture,’ ‘gram’ – meaning ‘drawing’ and ‘metry’ – meaning ‘measurement.’

This explanation makes your understanding clear.

Early advancements in the system and science of photogrammetry happened many years before the actual invention of appropriate things to apply the application.  As time rolled on, the theories became a certainty, and the essential technologies came into existence.  The timing when all these things evolved was a crucial time.

The scope of photogrammetry

Photogrammetry is one of the most extensively and technically preferred means for producing maps. Significant development originated in European nations and later spread over into Canada and the U.S. In the early 1900’s, an International Society came into the formation for serving as a collaborative and collective house for the progress of this science. The fields of Remote sensing and Photogrammetry widened their horizons in recent years. As per consideration, to include the investigation of diversified media, the images are still the primary root of information.

Branches

There are two distinct branches when it comes to the application of photogrammetry.

The primary department requires precise estimations and calculations regarding the shape, size, and position of graphics features.

The second branch deals just with identification and description of the detailed features.

In both the cases, a specially designed accurate camera system takes the pictures.  The camera, therefore, is the source of all capturing of data and plays a vital role in any relevance.  The photo calculating devices, as well as the final system of output and interpretation, also are the significant areas of concern.  These three tools; camera, a mapping device, and production medium, will eventually define the status and application of photogrammetric measurements.

Why is photogrammetry so useful?

Notably, there are several reasons.  Since photography is primarily of the ‘non-contact’ category, it presents a different way of perceiving and documenting information, without the necessity of a physical appearance.  This statement holds true in the state of aerial photogrammetry.  Aerial cameras provide the facility to photograph difficult, hostile or dangerous matter, with scarce or no risk to material and group.  You can consider military functions as an example of this situation out of many others like it.

Additionally, there are numerous advantages of aerial photogrammetry applied widely in the nonmilitary application as well.  Like, Engineers, Designers, and Planners also use mapping and pictures.  Therefore, the resulting list represents these applications:

• Natural disaster
• Environmental studies
• Land use and planning
• Construction
• Site development
• Insurance studies
• Real estate
• Surveying
• Mineral and Geotechnical research
• Agricultural forecasting
• Civil engineering

Within the streams of nearly all services, there is a demand for specific mapping remarkably.  With the opening of technology, the usefulness of photogrammetry in above-mentioned and other areas is almost limitless.  Also, mappings, as well as other techniques, play an advanced role in satisfying the public desires for comfort, transportation, and ease.

Conclusion

You need to know the importance of such fields which are not into the limelight but give tremendous opportunities to work. Think out of the box for your career.

Learn UAV In Photogrammetry & Transformation Of Aerial Photogrammetry

Introduction to what is UAV?

UAV stands for Unman Aerial vehicle. It is the technology used in Photogrammetry tech for obtaining 4D images for mapping. UAV (unmanned aircraft/aerial vehicle) system creates 4D mapping outputs and 3D landscape models or photographs. The UAV Photogrammetry in future will play a vital role in the emergency rescue, rehabilitation or reconstruction, new or rural construction, development of digital cities or Smart cities, monitoring of geographic situations, AEC industry and multiple other areas.

UAV Photogrammetry is the technology that can also be universally used.

The areas where the UAV techniques imply:-

Environmental protection, mineral resources exploration, marine environment monitoring, land use investigation, water resources development, crop growth monitoring and yield estimation. Also in agricultural operations, natural disaster monitoring, and assessment. City planning and municipal management, forest pest and International Journal of Control. Also including Automation disease protection and monitoring, public safety, national defense, digital earth and advertising photography, etc. are also the sectors where the use of technology exists. The UAV Photogrammetry has a huge demand in the market.

Explore How UAVs have modified Aerial Photogrammetry

UAVs have recently grown broadly accessible to the business and commercial public. It is because UAVs before were used in military applications. UAV technology has entirely transformed the use of Photogrammetry in surveying because unlike aircraft or planes, they technically improve the technology’s essential strengths.

For beginners, the UAVs are easily available at low-cost. The availability of the UAV Photogrammetry has not only boosted the demand & popularity of Photogrammetry for surveying but also has built a unique market called as micro-mapping. Thus, it includes the topography or surveying of places shorter than 5 square kilometers.

Mainly, as the surveying had to do with manned aircraft, the projects or plans like these have been unprofitable or expensive. The high mobilization expenses and long projects deadlines made it challenging for conventional surveying firms to accept these jobs. However, UAVs that matches smoothly into a surveyor’s vehicle, operators can mobilize more rapidly. And can also develop these small projects in one day.

Furthermore, UAV Photogrammetry is versatile as compared to planes. As it comes to positioning, stages of elevation, and steering tight spaces. Thus it makes suitable for an extensive variety of jobs.

Examples- To solve the above obstacle, you can make use of drones. Several UAVs can also programme by using the unique flight path called “Waypoint.”. The drone’s waypoint technology allows it to pass accurately through tight areas which may be impossible for a human pilot to navigate in such areas. Thus, along with the drone’s dense size, that enables it to capture images under the tree awnings and other obstacles with ease.

Conclusion

In some regions, due to low elevation UAV Photogrammetry is with the procedure, fast, economical and other advantages. While a digital camera can modify and adjust the sensitivity of the ISO by changing the aperture, shutter, and fog on color, contrast, the brightness of the software. Thus it makes possible to capture a color image in the dark, cloudy or mist day. It is easy to get 4D mapping outputs with the help of full digital photogrammetric workstation. Low altitude UAV digital aerial photograph is an essential content of the actual-time data information system.

Mapping technology in access system is an excellent complement to existing aerospace aeronautics, image acquisition system. The primary means to deal with emergency surveying and mapping serviceis the necessary tool for critical areas of geographic monitoring conditions. It is a significant way to fast update of geographic information. With the constant growth of sensor technology, UAV Photogrammetry technology, communication technology and continuous growth of data processing software, UAV Aerial Photogrammetry system will more universally use on large-scale topographic mapping areas.

Source: https://blog.nibt.education/2018/03/uav-transformation-of-aerial-photogrammetry/

Photogrammetry: Latest Technology to Create Maps Using Drones?

Introduction

The use of drones is gaining tempo in recent years. Unlike manned aircraft, the drones can stay overhead for many hours. The drones are much cheaper than military aircraft and are flying remotely. Therefore, there is no danger to the flight crew.

The drone aircraft are in the news practically every day. There seems an immense use of drones in the construction sector which are helpful for construction professionals in various ways. In this article, we will learn to create maps using drones with the use of photogrammetry technology.

Drones (UAV- Unmanned Aerial Vehicle) are a buzzing word almost in every field these days. That means it is an aircraft, of any size or type, that flies by itself without onboard pilot or passengers. You may think of it as a robot plane, controlled either autonomously or via remote control.

Drones in Photogrammetry

The combination of light (photo), drawings and measurements are known as photogrammetry. Until recently, photogrammetry was a very particular niche within the geospatial industry. Well, it was a complicated subject accessible only to specialized experts. However, photogrammetry is gaining impulse and is becoming more and more universally available with the help of some easy courses to learn photogrammetry.

Photogrammetry is a now a field in which despite the need for some training to understand the basic, there are many useful applications such as creating 3D maps using aerial images.

What is aerial photogrammetry?

In a straightforward language, aerial photogrammetry is the act of placing a camera on a flying vehicle and taking several photos of the ground as it flies. The relevant images are being processed in a computer using particular software which will eventually generate a georeferenced and measured output.

Using this technique, the users can make measurements from photographs as well as giving a chance to photographers of pinpointing the exact positions of surface points. With the emergence and continuous evolution of computer imaging, the process of photogrammetry is becoming a lot easier and is, therefore, proving useful in the construction industry.

 Check the real heck here

Photogrammetric platforms are still carrying robust, sophisticated, expensive and exact sensors. Using such systems, the need for robust software to resolve photogrammetric issues is less relevant. The evolution of UAV (Unmanned Aerial vehicle) in photogrammetry has been a game changer.

The cameras are the essential gadgets of photogrammetry technology. These are the individual cameras which have the excellent focal length to get better picture quality.

While taking pictures the camera is commonly flying with its axis vertical, but oblique and horizontal (ground-based) photographs are also possible. The analytical and analog method accomplishes Data reduction and data conversion.

In vertical aerial surveys, we get adjacent photos overlapping each other.  The automated sensors of the operators superimpose the two images for 3D viewing.

A Close-Range Photogrammetry (CRP) is one of the types of photogrammetry. We will not see more of it, but in essence, it comprises of aligning cameras closer to a subject to measure building structure, revive forensic scenes, or model archaeological objects. It is also known as “image-based modeling.”

With the use of UAVs or the everyday cameras as well as the modern software’s, the analog geometry is now archaic. By analyzing every pixel in the images and comparing highly overlapping sets of images, software packages can compute back to the 3rd dimension unlike the human brain get a sense of depth from the two eyes.

Conclusion

With the use of 3D images, a photogrammetrists can create numeric models of natural systems. It immensely establishes the possibility of developing predictions and controlling the impacts of natural disasters. From earthquakes to tsunamis, we can now make easy predictions of the multiple forces of the natures.

Source:https://blog.nibt.education/2018/03/photogrammetry-latest-technology-to-create-maps-using-drones/

Learn What Is Photogrammetry and Its Various Applications

In this article, we are presenting a brief introduction to what is photogrammetry and its various applications for those who are new to this technology.

 What is Photogrammetry?

In a straightforward language, Photogrammetry is a technology that combines photography and geometry. It has a significant impact on the current architectural works.

As the name implies, Photogrammetry is a 3-Dimensional coordinate measuring method that makes use of photographs as the primary medium for measurement. The classical definition of the Photogrammetry is the simple process of deriving metric information about an object through measurements made on the photograph of that object.  Furthermore, photogrammetry is the science or the art of making measurements from the photographs. It means the measuring of features on photographs.

Photogrammetry uses the fundamental principles of triangulation called as Aerial Triangulation. In this method, a photograph gets snap from at least two different locations called “Line of sight,” and it can develop from each camera to points on the object.
The mathematical intersection of these lines can generate the 3D coordinates of the points of interest.

History of Photogrammetry

The Photogrammetry method was initially in use by the Prussian Architect in 1867 who designed some of the earliest topographic maps and some elevation drawings. The photogrammetry service in the topographic mapping is well-established but in the current scenario, the application of photogrammetry is common in the fields of architecture, engineering, forensic, underwater, medicine and much more for the production of accurate 3D data.
The term photogrammetry describes from the three simple words:
‘Photo’ – Light
‘gram’ – Drawing
‘metry’ – Measurement
“Photogrammetry means Light Drawing Measurement”
The output of this method is typically a map, drawings, measurement or a 3D model of some real-world objects. Many of the maps we are using are generated with the help of this technique, while the photographs are taken from the aircrafts.

Application of Photogrammetry

The categorization of the photogrammetry is based on the camera location during the actual photography. On these terms, we have Aerial Photogrammetry, Terrestrial Photogrammetry and Space Photogrammetry.
Now let’s understand each application of Photogrammetry in detail.

Aerial Photogrammetry
In this type of photogrammetry, the cameras are launch on a machine that flies aircraft and therefore takes pictures. These pictures are useful in generating the measurements. In this case, for the statistical comparisons, at least two photos of the same object or surface are clicked. This type of photography uses special design planes.

The aircrafts fly over a preset piece of land, pointed with a particular landmark. The camera speed is controlling accordingly to the speed of the plane. Also, the height of the plane from the land is initially defined. The stereo-plotter (an instrument that allows an operator to view two photos at once in a stereo view) processes the photographs. The photographs are also useful in automation processing for Digital Elevation Model (DEM) creation.

Terrestrial Photogrammetry

It is this kind of Photogrammetry technique in which the camera is usable in a stationary position, and hence photographs need to capture from a fixed, known position on or near the ground. The camera tilt and other specifications are in command. Photo Theodolite is a unique instrument that utilizes in exploring the photographs.

 Space Photogrammetry

The space photogrammetry adapts all the aspects of extraterrestrial photography as well as measurements wherein the camera is non-moving on the earth or place on artificial satellite or in the space.

The term Photo Interpretation is applicable to that branch of photogrammetry wherein aerial or terrestrial photographs utilize to calculate, analyze, classify and interpret images of objects that are visible on the photographs. As a result, Photogrammetry is a combination of measurement and interpretation of a particular object.

Advantages of Photogrammetry

Photogrammetry has numerous advantages that are beneficial in modern construction as well as various other sectors like:

• Covers large areas quickly.
• The photogrammetry technique is cost-efficient.
• The method is the easiest way to obtain or access information from the air.
• The photographic images illustrate great details.

Application of Photogrammetry

• To quickly verify the spatial positions of the ground objects.
• To prepare topographical maps (surveying/mapping).
• Helpful in Military/Artificial Intelligence.
• For the interpretation of Geology/Archaeology.
• Analysis of crop damages due to floods or other natural disasters.
• To prepare a composite picture of ground objects.
• To relocate existing boundaries of properties.
• Helpful in the field of medicine.

The photogrammetry can generate a data set that will help many organizations or the stakeholders, therefore, helping to create most efficient and effective plan for any construction project.