What is Photogrammetry Surveying?

What is Photogrammetry Surveying?

Photogrammetry surveying or Photogrammetry is the study of making accurate measurements with pictures or digital photo images to locate features on or above the earth’s surface.

When broad area mapping is required, photogrammetry has evolved into a reliable replacement for ground surveying tasks.

Albrecht Meydenbauer, a Prussian architect, created the word photogrammetry in his 1867 article “Die Photometrographie.”

The phrase “photogrammetry” is derived from the word’s “photo” and “meter,” and it refers to measurements taken from images.

Photogrammetry is defined classically as “the art, science, and technology of acquiring trustworthy information about any physical object and the entire surroundings.”

This method entails a procedure of documenting, measuring, and analyzing terrestrial and aerial pictures.

Photogrammetry is considered an art form since obtaining accurate measurements necessitates the application of specific talents, techniques, and decisions made by an individual.

Photogrammetry is both a science and a technology because it takes photographs and alters them with technology to get meaningful findings.

Modern photogrammetry employs picture references and image types other than photographs, such as radar scans.

Proper project design, image retrieval, image processing, control data for image correction, data accumulation, and presentation of end product outcomes comprise the photogrammetric process.

The photogrammetric method yields coordinate values of individual points, a realistic depiction of the earth’s surface (topographic map), or a reformed image of the earth’s surface with map-like properties (orthophoto.)

Photographs for photogrammetry are taken with a specialized (metric) camera, a standard camera, or digital sensors.

The photos are acquired and recorded using a tool mounted on a satellite, an aircraft, or a tripod (terrestrial photogrammetry) set up and mounted on the ground.

Photogrammetry’s fundamental principle

Photogrammetry’s core principle is triangulation. So-called “lines of sight” can be created from each camera to places on the object by obtaining images from at least two separate locations.

Because of their optical character, these lines of sight (also known as rays) are mathematically intersected to give the 3-dimensional coordinates of the places of interest.

Theodolites employed triangulation as a coordinate measurement principle as well.

If you are familiar with these tools, you will notice that photogrammetry and theodolites have many similarities (and some differences).

Even closer to home, triangulation is the process through which your two eyes work together to determine distance (called depth perception).

Types of photogrammetry surveying

There are two types of orthophoto surveying:

Interpretative photogrammetry

Through rigorous and methodical study of photographic pictures, interpretative photogrammetry entails recognizing and classifying objects and determining their value.

These photos were produced using satellite imaging that detects energy in wavelengths.

This serves as the foundation for remote sensing (art or science of gathering information about an object or image without actually coming into physical contact).

Photo interpretation is the study of photographic images, whereas remote sensing is the utilization of data collected from remote sensing sensors as well as the analysis of photography.

Metric Photogrammetry

It entails taking exact measurements on pictures and other data in order to identify the relative locations of points.

Planimetric mapping and topographical mapping are two common applications of Metric Photogrammetry.

Applications used to calculate distances, altitudes, areas, volumes, and cross-sections using photographic measurements in order to create topographical maps.

Aerial images are most commonly utilized for this purpose, however terrestrial photographs are also employed on occasion.

Photogrammetry surveying applications

Topographic mapping, architecture, engineering, manufacturing, quality control, police investigation, cultural heritage, and geology are all applications of photogrammetry to mention but a few.

In Architecture

In Architecture/engineering photogrammetry is important in the process of building and maintaining structures.

Topographic Mapping

In topographic mapping it can be used to reveal elevations, ground surfaces, vegetation, and more.

In Engineering

Photogrammetry is often employed in Engineering projects such as architectural planning, civil engineering (seismic control), highway construction and maintenance, mine surveying, structural design (Steel structures), traffic surveys (road conditions), offshore oil exploration and production surveyors survey rock formations on land or underwater.

In Quality control

Photogrammetry may be employed in quality control by manufacturers of various products to ensure accuracy and precision.

Quality control is essential to the safe transportation of goods, so that they are what consumers expect them to be.

In Police Investigations

Some Photogrammetry surveying applications used by police investigation includes crime scene mapping, accident reconstruction and fire mapping.

By creating a 3-D model of a crime scene, police are able to better understand the events which transpired.

The information gathered by this method is extremely useful to investigators in creating a three-dimensional picture of an event.

In Cultural Heritage

Cultural heritage and archeology can employ photogrammetry surveying to preserve the remnants of ancient societies and their structures.

For cultural heritage, a high-precision laser scanner may be used to scan the structure into digital form.

In Archeology

As for archeology, this technique is often used to scan the surface of a site, then the data can be converted into three-dimensional models to reconstruct the original form.

Geology may use photogrammetry surveying to map out rock formations and features that may be useful in providing information on how they were formed.

In GIS

Finally, GIS (Geographic Information System) may employ photogrammetry surveying to map points on the earth’s surface for further processing in a computer.

Photogrammetry for Geodata Science

The geospatial industry relies heavily on photogrammetry. The growth of the high-tech industry and the advent of digital cameras has resulted in lighter, more precise equipment and streamlined procedures. There has been a significant decrease in cost and increase in productivity over the past decade.

Photogrammetry’s significance

Among its applications are satellite tracking of relative location changes in all Earth conditions.

The quantitative results of photogrammetry are used to guide and match the results of computational models of natural systems, assisting in the invalidation or confirmation of new theories, the design of novel vehicles, or the development of new methods for predicting or controlling the consequences of earthquakes, tsunamis, and other weather types.

Photogrammetry can also be used to solve triangulation, trilateration, and multidimensional scaling problems.

In the simplest case, if the scale (s) of the picture is known, the distance between two points on a plane parallel to the photographic image plane can be estimated by measuring their distance on the image.

Advantages of Photogrammetry Surveying

Below are benefits offered by photogrammetry surveying

1. Photogrammetric techniques produce highly accurate findings, making them very reliable for mapping and other applications.
2. The primary benefit of photogrammetry is the ease and speed with which data may be acquired.

Photogrammetry can assist in gathering photographs, analyzing the data to obtain measurements, and converting them to a 3D map in a short period of time and at a low-cost using UAV, UAS, or satellite imagery.

3. It provides a large or broad picture of the mapped area by utilizing both topographic and cultural land surface elements. This enables other studies to make better use of similar data.
4. The acquired data is permanent and accurate, and it captures the condition at the moment the images were taken in both pictorial and metric versions.
5. Because the information acquired is permanent, it is much easier to re-survey or re-evaluate the site to obtain any missing information without wasting time.
6. It is simple to take images of remote areas and difficult-to-reach locales using UAV, UAS, or satellite imagery photogrammetry. This also reduces the risk to the crew’s safety while scanning potentially risky areas.
7. It is simple to take images of remote areas and difficult-to-reach locales using UAV, UAS, or satellite imagery photogrammetry. This also reduces the risk to the crew’s safety while scanning potentially risky areas.

Disadvantages of Photogrammetry Surveying

The following is a summary of the downsides of using photogrammetry for surveying.

1. The main disadvantage is that photogrammetric surveys are impossible to conduct in the absence of light. It cannot project its own light source, making it difficult to snap images when the light source is dim.
2. It cannot be utilized for accurate readings when there is limited visibility in the region, which might be caused by seasonal phenomena like as snowfall or rains.

The accuracy of the measurement is not achievable if there is vegetation or a tree canopy that can impede the camera’s line of sight.

3. The precision of the measurements is strongly dependent on the flight height.
4. Because photogrammetry surveys are digital, they are vulnerable to hacking and data loss due to viruses.

Photogrammetry classification

They are two:

• Aerial photogrammetry – Aerial photogrammetry is the use of aircraft to capture aerial images for GIS data collection.
• Terrestrial photogrammetry – Terrestrial photogrammetry uses a camera on a vehicle to capture images of the ground.

In Aerial Photogrammetry

An Aerial Photogrammetry survey is where an aerial camera sends a digital image to the ground. This image is then processed and compared with a data base of known points such as survey marks, satellite images, or terrestrial maps of the region.

Aerial photogrammetry allows for accurate marine surveys and is especially useful in areas that are difficult to access, for example forests or mountainsides.

In Terrestrial Photogrammetry

Terrestrial photogrammetry uses a camera to capture images of the ground. The images can then be used to measure the distances between points on the image and on known maps of the area.

This is a very useful technique because it is relatively inexpensive, requires little pre-scanning, and can be carried out by one person in a short amount of time.

FAQs

What is aerial photography in surveying?

Photogrammetry, often known as aerial photography, is a field of surveying that deals with the creation of maps such as planimetric or topographic maps by compiling a large number of images taken in that area.

What is photogrammetric survey?

Photogrammetric surveying, also known as photogrammetry, is the science and art of obtaining accurate measurements through the use of photographs for a variety of purposes, including the creation of planimetric and topographic maps, soil classification, geology interpretation and military intelligence acquisition.

What is flying height in surveying?

To calculate the AGL, first establish the average height of the terrain and subtract it from the altitude above sea level.

This will provide you with the average flying height above ground. A camera with a 152 mm focal length, for example, captures an aerial photograph from a flying height of 2280 meters above ground level.

What is photogrammetry method?

Photogrammetry is the science and technique of acquiring accurate information about physical objects and the environment by recording, measuring, and interpreting photographic images, patterns of electromagnetic radiant imaging, and other occurrences.

What is aerial mapping used for?

Aerial surveys can be a valuable tool for planners. Satellite imaging and very high-altitude aerial photography reveal land use patterns that can be used in regional planning.

Periodic small-scale photography of metropolitan areas reveals patterns of urban and suburban growth.

What is GIS and photogrammetry?

The study of collecting accurate measurements from pictures and digital data is known as photogrammetry.

The photogrammetric technique frequently produces orthomosaic maps, symbolic maps, GIS layers, or three-dimensional (3D) models of real-world objects or settings.

What are the uses of photogrammetric survey?

Photogrammetry is a type of photography. Site planning, topographic mapping, earthwork volume estimation for proposed highways, a collection of digital elevation models (DEM), and image-based mapping are all examples of surveying applications (orthophotography).

What is photogrammetry and its types?

Photogrammetry is primarily concerned with accurately measuring three-dimensional objects and landscape features from two-dimensional images.

There are two types of photogrammetry: aerial (with the camera in the air) and terrestrial (with the camera on the ground) (with the camera handheld or on a tripod).

What is the principle of photogrammetry?

Photogrammetry’s core idea is triangulation, which is also known as Aerial Triangulation. Lines of sight can be created from each camera to points on the object by capturing images from at least two separate locations.

Why do we need photogrammetry?

The most typical application for photogrammetry is the creation of maps from aerial photographs.

It is both cost-effective and accurate, allowing planning bodies such as architects, local governments, and construction workers to make clear, informed decisions about their projects without having to scan the landscape for months.

How is photogrammetry technique used in surveying and mapping?

Photogrammetry is a technique for surveying and mapping that employs photographs. The fundamental principle of photogrammetry is triangulation.

Taking images from at least two distinct positions where a line of sight may be created from each camera to points on objects.

Photogrammetry can be classified into the following categories: There are two forms of photogrammetry.

How is photogrammetry used in construction?

Photogrammetry is a type of 3D scanning that employs pictures and triangulation to build an accurate model of a location or structure.

Photogrammetry can be used to monitor progress and assess problems as they arise during construction. HoloBuilder Inc. provided the image.

Is photogrammetry remote sensing?

Remote sensing is a technology that is similar to photogrammetry in that it takes information from imagery. The name is derived from the notion that information about objects and features is gathered without any physical touch with them.