Site Surveying: Mapping

Combining high resolution cameras with GPS-enabled aerial platforms, dronesurvey.HK is able to quickly and efficiently create accurate, georeferenced 3D maps, orthophoto projections and digital surface models of your site, including volume and distance measurement and multiple data layers at levels of detail never before imagined.

Our drones enable the creation of detailed, precise orthomosaic maps, with accuracies down to at least 5cm per pixel. From these, you can quickly and easily extract elevation and volumetric data, or monitor progress over time.

Speed up site development, monitoring and survey processes using drone-captured orthomosaics with pinpoint accuracy.

What’s an orthomosaic? Essentially, a grid of stitched-together, geometrically-corrected photos that accurately represent a portion of the Earth’s surface.

In the Cloud

Until recently, orthomosaic image processing required some pretty heavy computing power – processing hundreds of high resolution images into a working ortho-photo set could take a lot time (and a lot of coffee breaks!).

It’s still processor-intensive, but now through a number of cloud-based map processing solutions, it’s possible to leverage the power of distributed processing in the cloud, vastly reducing the time needed to process and deliver detailed othomosaic maps.

dronesurvey.HK leverages the best of these online solutions, selecting the system and solution most suitable for your job, and your specific requirements.


Volume-measure-demoMost of the cloud-based processing solutions also offer web-based volume measurement tools, making the measurement and tracking of stockpile or excavation volumes quick and easy. Measurements can be made directly from within a web-browser, and can be shared with others, or stored to track progress over time.

Google Maps

Yes, you could just use a Google Map of your site, but with a dronesurvey.HK orthomosaic map, you get a precise, up-to-date perspective on things, with high resolution imagery that you control. Google’s satellite images tend to date quickly (especially in Hong Kong!), and generally lack the resolution needed for any precision work. Of course, you can always integrate your site orthomosaic onto a larger Google Map / Google Earth region as well – we can help with that too!

Georeferencing and Projections

Mapping-GIF-animation-smallFor additional precision, dronesurvey.HK also offers georeferencing, aligning images to known points on the ground. This is not always required (it depends on your needs), but with georeferencing, you can accurately reference your map and use it as an overlay in many GIS systems, or in Google Earth.

On top of that, we can export your maps using custom projections for any EPSG code, making it faster and easier for you to analyse your maps in a local coordinate system of your choosing. Different projections are used to minimize distortion for different purposes. Some map projections, such as those used for large, global maps, aim to distribute the amount of distortion fairly evenly across the globe. Other projections are intended to minimize the amount of distortion in a specific area – hence local projections.

We can offer GeoTIFF export in two standard projections:

  • WGS84/EPSG:4326 (a widely-used projection for desktop software like ArcGIS)
  • Web Mercator/EPSG:3857 (used by most web applications such as Google Maps)

Or let us know your preferred EPSG projection and we can work with that.

Sample Maps

Golf Course Sample, Hong Kong:  This orthophoto map was generated from 67 geo-tagged images, covering 12 acre / 5 hectare section of a golf course in the New Territories, at a .5 inch/pixel resolution from an altitude of 120 ft / 36.5 m about ground level.

Olympic Training Centre, California: This georeferenced orthophoto map was created from 1133 geo-tagged images. An area of 234 acres / 95 hectares was covered with 1.9 inch/pixel ground resolution from an altitude of around 360 ft / 110 m.

Excavation Site, Pennsylvania: This georeferenced photo mosaic and colorized relative elevation map were created from 1001 images. The 17 acre / 6.9 hectare site was photographed at a .5 inch/pixel ground resolution from an altitude of 150ft / 46 m above ground level.

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