Orthomosaic Mapping and Photomapping, Part 1

Aerial Drone Photography is the Ideal Technology for Orthomosaic Mapping and Photomapping!

Digital Elevation Model

Digital Elevation Model Topographical Map

Realm of Possibilities

In this article, the term orthomosaic mapping is used to describe the orthomosaic photogrammetry mapping technique, which is a computationally-intense method that yields position and altitude information for each pixel in the map. The term photomapping is used to describe the use of photostitching software to generate large panoramic maps.

Our orthomosaic map deliverables include: ultra-high resolution 2D maps, 3D Digital Elevation Model (DEM) topographical maps, 3D models, and 3D point clouds.

Our Photomap deliverable is a 2D map image similar to Earth-type maps but with ultra-high resolution.

As implied, “high-resolution” means these map image files can be very large – on the order of 3-4 megapixels per acre. For example, an 80-acre map will have around 300 MP and a JPG image file of around 160 MB. Large files for sure, but the terrain detail is amazing!

Who Can Use Orthomosaic Maps?

Surveyors, Architects, and Civil Engineers are several of the many professions that use orthomosaic maps for their land development and construction projects. They have the budget for high-end software, which can further process our orthomosaic map products.

Real Estate marketers and landowners may also need high resolution maps but don’t want to make the significant investment in photogrammetry software. For these users, we offer photomaps, which provide beautiful full-color map images. More on photomapping in Part 2.

Either way, these maps have high enough resolution to detect very small features. For example, a 1 foot by 1 foot object is represented with around 100 pixels. Tract size can range from less than one acre to thousands of acres.

What Makes Aerial Drone Orthomosaic Maps So Special?

Three dimensional computing is at the heart of calculating position and altitude information for each pixel. The numerically-intense software that does this, to my knowledge, hasn’t been made available for personal computers, so most users have to use online mapping services. For more detailed information on how this specialized software works, please refer to this article at ScienceDirect.com.

How Is It Done?

Orthomosaic mapping software requires many photographs of the landscape so each pixel gets multiple look angles. The software then assigns position and altitude information to each pixel. As you might reason, this is a very complicated process. To get good results, very high overlaps of the subject area are required – on the order of 75 to 90%. This requires that each ground point is photographed 16 to 100 times.

Aerial drones with precise GPS-based navigation are ideal for photographing landscape with this kind of precision. Hundreds or even thousands of high-resolution photographs are taken, typically looking straight down, and stored on the drone’s internal memory card. Back at the office, these photos are then uploaded to the mapping service and reconstructed by their orthomosaic software to create stunning, full-color maps, DEM maps, 3D models, and point clouds.

To achieve good results, the drone’s altitude must be around 4-5 times the altitude of the highest object, such as trees. The algorithms work best when there’s low wind and lots of leaves on the trees. Water can be a challenge due to its reflectivity. With less-than-ideal photography, the algorithms have difficulty assigning position and altitude information to the pixels. If done incorrectly, the resulting map either has strangely-shaped areas or areas that are blanked out.

Orthomosaic Map Deliverable Products:

  • 2D Map – full-color image of the landscape, including position and altitude information.
  • Digital Elevation Model – color-coded for elevation, any color scheme is possible as well as contour lines.
  • 3D model – full color three dimensional image. The model can be viewed on-screen from any perspective.
  • Point Cloud – typically viewed with high-end software. It’s a full color 3D model using points.

In part 2, we’ll examine photomapping, which will be of particular interest to real estate marketers and landowners.

Instant Photo and File Delivery, Update

We have improved our method to deliver your photo and video files, so this is an update to our blog “Instant Photo and File Delivery,” posted in March.

We Deliver Your Files via Google Drive

We Deliver Your Files via Google Drive

We Deliver Your Photos and Videos Fast!

Often, our clients are on site so when we finish our aerial drone photography session we copy the files to the client’s computer or deliver them on a USB thumb drive.

When the client is not on site, we deliver their files within two business days using our Google Drive account. The process is easy and no software needs to be installed by the client. We send a link via e-mail and the client simply clicks on the link to arrive at a shared folder where they can view and download their files.

Does Google Drive Work For Smart Phones and Tablets?

We haven’t found a platform yet that doesn’t work with G-Drive! Desktop computers seem to be a little easier to work with for most people, but G-Drive can also be used with smart phones and tablets. Although we haven’t tested all of the devices out there, we have been successful with the latest Android and iOS operating systems.

Android

Click on the link in our e-mail and the G-Drive folder should appear. Select the files and then download. The files will appear in your download folder and can be viewed or copied from there.

iOS

Click on the link in our e-mail and the G-Drive should appear. Select the file to view, then save to your file system. You may have to save your files one at a time.

Note: Earlier versions of iOS may give you access to the device’s local file system. Our iPad 9.7 Pro is running iOS v12, which makes it much more difficult to save files to the device’s local file system. The Apple way is to save your files to “My Drive” which means saving to your account on iCloud, DropBox, Google Drive, etc. If someone finds a better way, then please send me a comment.

Video Production Sound Track

Recording Your Voice Using A Cell Phone

Recording Your Voice Using A Cell Phone

I mentioned in last year’s blog on post-production processing that the sound track can be tricky. Especially when the client wants music that they’ve heard from other media sources (such as the radio, TV, concert, CD, etc.) These sources are almost always copyrighted and the owners can (and probably will) track down violators and demand compensation.

Beware, The Music Industry Has Their Ways!

Last year, I know someone who came up with a slick idea to digitize a 1960’s record album and used about 30 seconds of it on a YouTube video. YouTube recognized the song, identified the copyright holder, and gave them a warning! So, you can’t be too careful about copyright violation.

How Much Will It Cost For A Music Track?

The cost for a music track depends on the service. For example, TripleScoop licenses 3-5 minute music tracks for $60 to professional photographers (this is my class). However, for small businesses, such as real estate listings, their licenses run $120. Large businesses will cost even more.

I once had a client ask for a specific song and I had to track down the copyright owner. It happened to be a big Hollywood outfit, Universal Music Publishing Group. They quoted $1500 per month to play this track in a small business marketing video! Needless to say, this expense was not in the client’s budget.

In addition to the cost for acquiring a commercial music license, there’s also the time required for the post-production part of it. This can be significant and includes searching for suitable music, getting a quote for the license, getting the client’s approval, purchasing the license, and coordinating the audio track with the video. Sometimes, several iterations are required until the client approves the finished video.

Are there penalties if you get caught by the copyright owner? Yes, and they’re covered by U.S. federal law under Title 17 US Code Section 106. Damages can include fines and court expenses.

The Path of Least Resistance Often Works Best

The challenges above are among the reasons that a client’s voice track works so well. First, the client owns the copyright on their own voice recording. Also, it personalizes the video to their prospective clients.

How to Record Your Own Voice Track

Clients often take my draft video and practice their narrative with it. Then record their voice using a cell phone (e.g. using Voice Recorder/Voice Memo) and send me the .M4A (MPEG-4 Audio file). Such a choreographed voice track works well for my post-production work. When appropriate, I can add a 15 to30 second stock music snippet to the introduction and end.

You will find examples of sound tracks in the videos posted to my portfolio page.

Instant Photo and Video File Delivery

FAD-Photo Delivers Your Photo and Video Files via Dropbox for Super Fast Service

We Use Dropbox for Instant File Delivery

FAD-Photo uses Dropbox.com for instant photo and video file delivery. We upload your files to our account and send you a link so all you have to do is click on the link and then click the download button.

In some cases, you may have to wait up to 10 seconds for the download button to appear. When it does, then click to download the file to your computer or smart device.

When two or more files are delivered, we use 9Zip, a generic Windows 10 application. It combines your files into one “Zip” file and then we upload it to Dropbox. The Zip file you download will display like a folder in most operating systems. For example, with Windows 10 you can open, play, and copy your photo and video files to wherever you need them.

Do I Need to Install any Software for Dropbox or 9Zip?

No worries, you won’t need to install any software or set up your own account.

What is a Zip File?

Zip files make more efficient use of your computer’s storage space by reducing the file size and combining multiple files into one file. It works well and the process is lossless – that is, there’s no decrease in your photo’s or video’s quality. The good news is that you won’t have to install any software on your computer, tablet, or smart phone.

Once downloaded, your operating system will treat the zip file very similarly to a folder. Simply click on the zip file just like you would a folder. Your files can then be extracted (just right click) or individually copied to any location you desire. If you’re using Windows 10, you can view/play your files by clicking on them in the zip file. Many other operating systems work similarly.

What About My Tablet or Smart Phone?

Smart devices, such as Android, treat the Zip file a little differently. Use your file explorer to find the zip file, typically in the Download folder. Then select each file (or all) and extract them. Your files will be found in the Download folder and can be opened, played, and copied to wherever you need them. Apple devices running iOS use a similar process.