Precision elevation and contour mapping using drones

When it comes to elevation and contour mapping, there’s more than one way to get to a result … but it’s not always the result you need. Traditional sources of contour maps are often based on satellite data with contour intervals at 10-30 meters apart. Elevation and contour mapping for design and engineering estimation requires a contour interval of at least 50 cm apart and precision engineering often requires contours at 25cm intervals.

To achieve 25cm contour interval accuracy, you need mapping which has a vertical accuracy of 12 cm or better. This kind of mapping accuracy requires precision ground control at centimetre or better accuracy and a very high density point cloud. The error chain in data processing needs to be carefully managed and tracked to ensure the accuracy of the model is not lost when it’s converted to elevation and contour maps.

Engineers and designers traditionally rely on professional surveyors to achieve this level of precision, but traditional survey methods are expensive and time-consuming. It often takes days just to get a quote or proposal from a surveyor, then a week or more before someone can go out on site. If it’s a large site, the surveyor may be onsite for a week or more and charge you $10-20,000 for their time. Even then, it can be weeks before you see the results.

Using a registered surveyor is essential in some situations, but they are not always required to get the data you need to move ahead with your development project, land use project, construction planning activities and the like. LIDAR surveys and aerial orthographic surveys, managed by the right team, can deliver similar results to a traditional survey in a fraction of the time and at a fraction of the cost.

Queensland Drones has the right team and offers two precision mapping options:

(1) Aerial LIDAR Mapping, best suited to rugged and heavily treed land, with a precision of as little as 15cm horizontal and 45cm vertical. As we can use existing aerial data sources, we can usually deliver results within 2-3 working days.

(2) Aerial Orthographic Mapping, best suited to more open land (less than 70% tree cover), with a precision of as little as 1cm horizontal and 2cm vertical. These surveys require a site visit and use of local ground control points, but can usually be completed and delivered within 3-7 working days depending on land size and location.

The types of products we can provide you with include:

  • A Digital Elevation Model (DEM) of your site or we can analyse this further to produce
    • Stream channel location (drainage lines for protective earth works)
    • Catchment boundaries (for dams etc)
    • Stockpile changes (for quarries)
    • Excavation volumes (for earth works costing)
    • Roadway location
    • Cross section profile analysis (for stream rehabilitation)
  • A Digital Terrain Model (DTM) from which we can produce
    • Line of Sight analysis for building location
    • View-shed analysis for viewing platforms and trail lookouts etc.
  • Contours for water management and infra-structure planning including
    • Paddock design and planning
    • Contour bank location
    • Keyline farming
    • Hiking and mountain bike trail layout
    • Diversion banks for increased water collection or protection from overland flood flow
aerial contour mapping geolocation sample

An example of the output is this geo-referenced PDF file showing the boundaries, contours and final ground control point locations together with KMZ/SHP files and accuracy report. Outputs can be PDF files for printing, shape or tab files or TIFF rasters as appropriate, DWG/DWX files for CAD use, or KMZ/KML files for use in layered GIS systems like Google Earth or the new Queensland Globe.

Queensland Drones uses professional, GIS-grade GPS equipment to ensure its aerial mapping products are supported by precision ground control data. Our map processing uses the latest GIS mapping tools and processes, supported by a post-graduate qualified GIS specialist. Our final report includes a comprehensive accuracy and error correction statement you can give to your surveyor for validation of accuracy and certification of results.

To find out more about how our aerial contour mapping and elevation mapping services can help you, give us a call now or request a callback using the buttons below.