Dear Prof. Brutto

I'm also new to this field of digital mapping through the use of UAVs. Nevertheless I've collected some useful papers which I thought would be good to share. Most of the questions which you raised are answered in these research papers. The first paper deals with the general introduction followed by specific applications of UAV in various domains. Please feel free to get in touch, I've some more papers. Couldn't upload all due to limitation of uploading only 10 files!

Dear Prof. Brutto

I'm also new to this field of digital mapping through the use of UAVs. Nevertheless I've collected some useful papers which I thought would be good to share. Most of the questions which you raised are answered in these research papers. The first paper deals with the general introduction followed by specific applications of UAV in various domains. Please feel free to get in touch, I've some more papers. Couldn't upload all due to limitation of uploading only 10 files!

Mauro

We comezado using UAV in our investigations on the coast. A first paper ( An initial evaluation of drone-based monitoring of boulder beaches in Galicia, northwestern Spain) has been accepted in Earth Surface Proecces and Landforms. I can give you when you first press version.

You can see in my profile, a poster presented in Paris in August 2013.

Dear James and dear Augusto

thanks for your help but I think that your answers don't fit my question. I know very well all UAV applications but I'm looking for a specific use of this technology: UAV to produce topographic maps, not for cultural heritage or for geomorphological study, but only to obtain vector cartography. This process is a standard activity in aerial photogrammetry but not in UAV applications.

Best Regards

Mauro

Dear Professor Lo Brutto,

Uptill now I performed four field campaigns with a helikite, and two other with a multi-rotor drone. In a recent publication I made an orthoimage with a UAV (1cm resolution), and I just finished a manuscript (which I'm submitting soon) in which I made a detailed topographic map of about 20 ha with a multirotor UAV.

the scale of these maps: it's simple, the lower the altitude of the UAV, the higher the resolution, the larger the scale of your imagery.

However, with low-altitude flights, the speed of the UAV should be decreased (or the shutter speed increased, if the light conditions allow it) to avoid blurry images, and here comes the difference between fixed-wing and multi-rotor. The fixed-wing has a minimum speed, and therefore puts a constraint on the resolution of the imagery (but the fixed-wing is more efficient in terms of battery consumption with respect to the multi-rotor).

the size of the area to be surveyed: much is possible, but of course, it depends on the time you have available. It took me 3 hours to capture a 20 hectare field with 1 cm/pixel resolution (UAV altitude about 20 m), with a multi-rotor drone, but before that we had to place the ground control points and measure their coordinates with a total station (which also took nearly 2 hours with 2 or 3 people).

Thus, the lower the image resolution you want, the less time it will take to photograph a certain area because your UAV can fly higher (which decreases its total flight distance to cover the area) and faster while still getting sharp pictures. You also should keep in mind that batteries have limited energy (for they had to be changed and recharged about every 30 minutes, in our case), and that one is usually not allowed to control its UAV beyond a certain radius from yourself, depending on the license you have (in our case 500m)

Dear Mauro,

I think that UAV technology has not reached the due maturity yet for standard mapping and there are mainly two reasons for this in my opinion. First it is for security reasons over inhabited areas and with respect to the other flying carriers (helicopters etc). With regards to this, new regulations in Italy are quite strict. To map big areas with a fixed wing UAV you cannot visually fly the UAV. Second it is because it's still not efficient to use small format (non metric) cameras as they need lots of GCPs on the ground or a quite expensive GNSS/INS system on-board. The camera interior orientation instability is a quite big problem if accurate results are expected. As far as I know only underdeveloped countries or where strict regulations have not been stated yet are working on this topic.

I think UAV mapping is feasible for post mapping disaster or mapping of unpopulated areas, that is why there are mainly reports and publications about these applications . At the moment I think there are still too many risks to work without visually controlling the UAV.

Regards,

Fabio

Mauro,

I work with UAV for topographic data extraction, hence DTM and DSM in the University and also i'm an owner of a survey company that provides services with UAV. You can access my company site www.lci.eng.br where you can find some services we provide. Extract vector information from UAV data it is not a commom workflow, usually the clients need only the ortophotos and the contours from their areas. In 18 months of surveys only once we recived a request to generate vectors from the ortophotos. In my company i use a specific software for UAV data processing and it have a module that allows 3D vectors extration from stereo pairs, but manually. Feel free to contact me for any clarifications.

Regards,

Leonardo

hello,

What could be the scale of the topographic maps? depends on focal and height

our studies

at 80m - +/-1:4000

at 40m - +/- 1:2000

What could be the size of the area to be surveyed?

400m*200m (multi-rotor) 8-11minutes

2km*2km (fixed-wing) 40 minutes

What are the differences between fixed-wing and multi-rotor for these applications? fixed-wing usually used for large area while multi-rotor on specific area which required accurate data such as monitoring of slope...

regards,

Khairul Nizam Tahar

Regards.