Beyond the Scope of an Orthophoto Map

Some individuals have the misconception that the only thing that can be obtained from a drone is an orthophoto map. We will demonstrate that the 3D survey is unique by describing its capabilities, which include the processing of photographs taken by unmanned aerial vehicles (UAVs) for use in geodetic applications.

The Slovenian company Modri Planet, which previously offered geodetic services a few years ago, is responsible for the development of the 3Dsurvey program. In order to satisfy their own requirements, the Slovene people started developing a tool that would make the work easier and go more quickly. Because of the positive reception the product received from customers, it underwent consistent development and, in the end, became the primary focus of the company.

The image processing program known as 3Dsurvey is user-friendly and comprehensive, and it was developed specifically for use with Unmanned Aerial Systems (UAV). The application is compatible with hardware produced by a variety of different vendors. In addition to a comprehensive collection of measurement instruments, it provides a wide range of import and export choices.

Important basics

The relevant plane systems for your 3d modelling survey can be selected from a drop-down list within 3Dsurvey (they cover Poland and the world, according to the EPSG classification). For the purpose of defining altitude systems, we use appropriate geoid files (in a manner akin to how one would deal with GNSS), such as Kronstadt 86 or the new Amsterdam.

It is possible to import data from the drone (including information about the location of the camera) straight from an EXIF photo file (which is utilized by the majority of DJI, Parrot, or eBee drones) or from an external file (for example, for a FlyTech wing). We do not need to be concerned about the recording format when we are uploading the network points; at the import stage, we will have the freedom to adjust the separators or the order in which the columns appear. In addition to the more traditional function of indicating where the warp points are, the application also includes a mechanism for automatically detecting measuring discs. Naturally, this necessitates the utilization of predetermined indicators out in the field. Additionally, the development of the point cloud as well as the alignment of the photo block are both accomplished in an automated fashion. The technique results in the creation of a cloud that is extremely thick and almost completely free of noise.

Cloud Capabilities

It's possible that the point cloud is the ideal solution for individuals who are simply interested in measuring a "few" pickets. The tools that are available in 3Dsurvey for working with clouds make it possible to quickly classify data and create layers, such as landscape, example. You will find the functions for measuring stations, lines, and circles under the tab labelled CAD. We will either pin the region directly in 3D or collect the dimensions first. In addition to this, we will generate cross-sections, either manually or depending on the DXF file that was loaded. And it is precisely in scenarios like these that the authors' method can be proven to be quite practical. Not only will we produce cross-sections along these lines, but also "crossbars" of a specific size. After that, we are able to export them in either a 2D format (a PDF report) or a 3D format (e.g. CAD file).

You are also able to measure the height of extra points that are positioned in between the already existing points with this program. This is made easier by the tool for producing CAD points, which makes it possible to construct additional stations by simply identifying the region of interest and adjusting the density.

Does anyone among you take the time to test how much the cables sag? Definitely. Using a point cloud makes the process very easy to understand. And how about determining the height of the structure? It only takes two clicks to do so. The slopes of the roof, as well as the slopes of the slopes, are not difficult to ascertain in any way. We may derive a significant amount of information from a point cloud, which is a discrete record of the space in question.

NMT as well as mesh 3D

In 3Dsurvey, in addition to the point cloud, we will construct a numerical terrain model or mesh models, which are meshes that create surfaces. These models will be used in place of the point cloud. Visualizing or generating a true orthophoto map can be accomplished with the help of Mesh 3D. In turn, the process of constructing an orthophoto mosaic or orthophoto map requires the use of terrain models.

Users have been given access to a wide variety of editing tools by the manufacturers of the models. We can get rid of elements, make the surface smoother, or calculate mass balances by simulating changes in reference levels. These options are all available to us. Let us add here that not only is the volume measurement in the 3Dsurvey quite precise, but it is also, and perhaps most importantly, incredibly easy to perform and quick. It is sufficient to either design an envelope or use a pre-made CAD envelope, either of which will enable you to measure in the same spots at all times. In addition to this, we will compare either two models (which will allow us to obtain extremely specific information regarding changes) or the model with the project.

It is important to note that all measurements are automatically preserved, and at any time we can generate a report that includes a graphical depiction of the location, mass balance, as well as 2D and 3D surface. One or more items may be included in each report that we produce.

It is also important to note that users have the option of exporting the model to a LandXML file, which makes it much simpler to put projects into action. In a similar vein, there is the opportunity to generate contour lines, which can then be exported in either a 2D or a 3D format. Additionally, it functions as a form of model export for some older workbenches that may not always accept LandXML.

The actual orthophoto map as well as the orthophoto map

With a terrain model and a block of images that have been precisely aligned, we can build an orthophoto map with just the press of a button. It is an excellent resource for a wide variety of tasks, including validation and even the development of a map. Our model has an accuracy of around 2-3 centimetres, which is sufficient to account for all things located at ground level.

What should we do if, for example, we want to draw a building but we can't see one of the building's corners? There are two choices available. The first option, which is one that is utilized more frequently, is the substitution of the photo. After the user has selected an area that cannot be read, the application will immediately display any photographs in which the selected portion can be seen. After that, we decide on a new perspective and replace the missing piece. Utilizing the X-ray device is the second possible course of action (yes, the name intentionally refers to the X-ray examination). Next, a layer that was produced from the point cloud will show, looking very much like an x-ray, and on this layer, we will primarily observe edges.

Real orthophoto maps are yet another method of space depiction; these maps provide an unobstructed picture of rooftops and towering buildings. Both of these products will be exported to a variety of file formats, such as TIFF with georeferencing or the more common JPG with a localization file. There is an option to export the CAD frame in DXF, which can be used for apps that are unable to work with these formats; all you need to do is drag the image to the frame.

Keeping track of the findings and preparing reports

In 3Dsurvey, in addition to generating a report on the work that was completed (which details the phases of correction and accuracy, as well as the characteristics of terrain models and orthophotos), we also generate reports on measurements. A DOC file is created, which can be edited in more detail later on. Additionally, the application gives you the ability to take videos while you are flying virtually over the model. Because we need to sell the job that we've done, we will showcase the product in an appealing manner using this strategy.

Unfortuitously, the article has some restrictions, and it is impossible to include everything on just two pages. However, we hope that after reading this material, you will be able to view drones in a different light. It is a tool for modern surveyors and modern recipients, but that does not absolve us from the responsibility of ensuring that the things we sell are of a high enough standard.

If in need of the best site survey services, look no further than CAD Surveys Ltd. We have a team of experts who can use the latest drone technology to provide you with an accurate and up-to-date site survey. We can also create a 3D model of your site which can be used for various purposes such as planning and marketing. Contact us today to find out more about our services.