Orthophotos and DSMs/DTM derived from RPAS flights over the nature reserve Landschap De Liereman in Flanders, Belgium

Study area

Landschap De Liereman is a nature reserve situated in Oud-Turnhout, in the province of Antwerp, Flanders, Belgium. The area is managed by the nature conservation NGO Natuurpunt and consists of a diverse landscape of wet and dry heathlands, Nardus grasslands on siliceous soils, forests and transition mires, as well as some remaining arable fields and high-intensity agricultural grasslands.

Data collection

Data were collected by the Research Institute for Nature and Forest (INBO) with a fixed wing drone Gatewing X100 in 2015 (7 flights). RGB data were acquired using an off-the-shelf Ricoh GR Digital IV camera, with the following image bands: 1: red, 2: green, 3: blue, 4: alpha channel.

An additional flight campaign was commissioned by INBO and carried out by the Flemish Institute for Technological Research (VITO) in 2017 with a fixed wing drone SenseFly eBee. Multispectral data were acquired using a Parrot Sequoia camera, with the following image bands: 1: green, 2: red, 3: red edge, 4: NIR, 5: alpha channel. with a Parrot Sequoia camera. Raw data for this flight campaign are not available.

Data processing

The raw data were processed to Digital Surface Models and orthophotos by VITO in 2017. For the 2017 campaign by VITO, the outputs also include a Digital Terrain Model (DTM). Images with coarse GPS coordinates were imported and processed in Agisoft PhotoScan Pro 1.4.x, a structure-from-motion (SfM) based photogrammetry software program. After extraction and matching of tie points, a bundle adjustment leads to a sparse point cloud and a refined set of camera position and orientation values. From there, a point cloud densification and classification into ground and non-ground points was performed, leading to a rasterized digital surface model (DSM) and digital terrain model (DTM). Finally, a true orthomosaic was projected onto the DTM.

Coordinate reference system

All geospatial data have the coordinate reference system EPSG:31370 - Belgian Lambert 72.

Files

• Raw flight data: images and logs collected by the drone during flight. These files are zipped per flight, with the date (yyyymmdd) and flight number (x) indicated in the file name (flight_yyyymmdd_Liereman_x.zip). Raw data for the eBee flights are not available.
• Processed data: Digital Surface Models (filename_DSM.tif) and orthophotos (filename_Ortho.tif) stitched together from the raw data. The included flights are indicated in the file name (7 flights for 20151008_Liereman_1-4_20151009_Liereman_1-3_DSM.tif).
• Ground control points: not applicable for this dataset.

Cloud Optimized GeoTIFF

The most efficient way to explore the processed data is by loading the Cloud Optimized GeoTIFFs we created for each processed file. Copy one of the file URLs below and follow e.g. the QGIS tutorial to load this type of file.

• http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20151008_Liereman_1-4_20151009_Liereman_1-3_DSM.tif
• http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20151008_Liereman_1-4_20151009_Liereman_1-3_Ortho.tif RGB
• http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20170718_Liereman_eBee_DSM.tif
• http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20170718_Liereman_eBee_DTM.tif
• http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20170718_Liereman_eBee_Ortho.tif multispec

See this page for an overview of public INBO RPAS data.