Dataset Open Access

Orthophotos and DSMs derived from RPAS flights over the nature reserve Zwin in Flanders, Belgium

Vanden Borre, Jeroen; Klaas Pauly; Van Hoey, Stijn; De Reu, Jeroen; Desmet, Peter

Study area

The Zwin is a nature reserve situated along the Belgian North Sea coast, northeast of Knokke, in the province of West-Flanders, Flanders, Belgium. The area is managed by the Flemish Agency for Nature and Forest and consists of a tidal marsh, coastal dunes with Ammophila arenaria, dune grasslands and/or shrub (Hippophae rhamnoides, Salix repens), and a transitional grassland zone that stretches from the inner edge of the coastal dunes into the polders.

Data collection

Data were collected by the Research Institute for Nature and Forest (INBO) with a fixed wing drone Gatewing X100 in 2014 and 2015 (15 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. CIR (color-infrared) data were acquired using a NIR-enabled Ricoh GR Digital IV camera, with the following info bands: 1: NIR, 2: red, 3: green, 4: alpha channel.

Data processing

The raw data were processed to Digital Surface Models and orthophotos by the Flemish Institute for Technological Research (VITO) in 2017. 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. Ground control points (either artificially installed markers on the terrain, or other photo-identifiable points, measured on the ground with RTK GNSS) were used to further refine the camera calibration and obtain a pixel-level georeferencing accuracy. 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_Zwin_x.zip).
  • 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 (e.g. 6 flights for 20150709_Zwin_1-3_20150710_Zwin_1-3_DSM.tif).
  • Ground control points: fixed ground control points (GCP) were placed on 2014-04-07, coordinates of which are available in GCP_20140407_Zwin_fixed.tsv. These GCPs are visible (but fading over time) in all orthophotos except 20151012_Zwin_1-4_Ortho.tif which covers a different area. Additional temporary GCPs were placed on 2014-04-07, 2014-04-10 and 2015-07-09 (visible in orthophotos of those dates), coordinates of which are available in the respective GCP_yyyymmdd_Zwin.tsv file.

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/20140407_Zwin_1-2_DSM.tif
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20140407_Zwin_1-2_Ortho.tif CIR
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20140410_Zwin_1-3_DSM.tif
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20140410_Zwin_1-3_Ortho.tif CIR
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20150709_Zwin_1-3_20150710_Zwin_1-3_DSM.tif
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20150709_Zwin_1-3_20150710_Zwin_1-3_Ortho.tif RGB
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20151012_Zwin_1-4_DSM.tif
  • http://s3-eu-west-1.amazonaws.com/lw-remote-sensing/cogeo/20151012_Zwin_1-4_Ortho.tif RGB

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

This dataset was collected using infrastructure provided by INBO and funded by Research Foundation - Flanders (FWO) as part of the Belgian contribution to LifeWatch.
Files (84.7 GB)
Name Size
20140407_Zwin_1-2_DSM.tif
md5:f0b79c510d56b8c23c91ff3210a79df7
539.7 MB Download
20140407_Zwin_1-2_Ortho.tif
md5:379d851b6e7cce10ac7e0f6b9f736bc8
5.1 GB Download
20140410_Zwin_1-3_DSM.tif
md5:3ea0fb60abb3d627a242a6cca0d02bb9
615.2 MB Download
20140410_Zwin_1-3_Ortho.tif
md5:905ba796f1ce3b473f529d4feb31413d
5.7 GB Download
20150709_Zwin_1-3_20150710_Zwin_1-3_DSM.tif
md5:e9342307c3b557d38ac4b0fa420801d3
956.3 MB Download
20150709_Zwin_1-3_20150710_Zwin_1-3_Ortho.tif
md5:158d27040448a0e3eea9c89b9882152e
9.1 GB Download
20151012_Zwin_1-4_DSM.tif
md5:be9e27fc5e8a1b73dd5946d3c97217d6
983.9 MB Download
20151012_Zwin_1-4_Ortho.tif
md5:69686ef0dee4ab840ab29cf6aab6f74a
10.1 GB Download
flight_20140407_Zwin_1.zip
md5:0005c2f8bd568fc08348eb370867b331
4.1 GB Download
flight_20140407_Zwin_2.zip
md5:37a3c47588ee56397dc59a6fd27e2d6e
4.0 GB Download
flight_20140410_Zwin_1.zip
md5:a8311df02dfa8e1d431241374a7a80fe
3.6 GB Download
flight_20140410_Zwin_2.zip
md5:790f0079d8f2a97afbb5794ce1ed4e46
3.5 GB Download
flight_20140410_Zwin_3.zip
md5:8c72e6a427247d26a7be6fa9f22a74fc
2.7 GB Download
flight_20150709_Zwin_1.zip
md5:5cc09df0c8f6e071937c04a544ec30c1
4.0 GB Download
flight_20150709_Zwin_2.zip
md5:1cd364218daf301dc345f3ec2dfe97d8
3.9 GB Download
flight_20150709_Zwin_3.zip
md5:5ea93e55a166620d81d3d0ebda24648f
2.6 GB Download
flight_20150710_Zwin_1.zip
md5:dfcb8f2191169f3ed4d822a6cd97d608
3.5 GB Download
flight_20150710_Zwin_2.zip
md5:684688c87c0f9e8d905802c35780532f
3.4 GB Download
flight_20150710_Zwin_3.zip
md5:99908f611d5bea64695f1cc253c68ea5
3.8 GB Download
flight_20151012_Zwin_1.zip
md5:5599d7ae4e1d0a6bcd9ea8963a28f97d
3.0 GB Download
flight_20151012_Zwin_2.zip
md5:a7d6d5163343414722870d3439b56807
3.5 GB Download
flight_20151012_Zwin_3.zip
md5:c7a6ccbdeb8928a14d4b840c08c7a011
3.0 GB Download
flight_20151012_Zwin_4.zip
md5:f4f8f4f5b5d04e8c356c73d0bb6e5b09
3.0 GB Download
GCP_20140407_Zwin.tsv
md5:92a7426179bc088b7a861a9d44e2ebb8
508 Bytes Download
GCP_20140407_Zwin_fixed.tsv
md5:37d6023d40dcc1526a340365a54e05d5
1.9 kB Download
GCP_20140410_Zwin.tsv
md5:fd275f852540862e033a9651f6b84db0
511 Bytes Download
GCP_20150709_Zwin.tsv
md5:d1242d0ded4be675821198d43ccaa121
934 Bytes Download
63
101
views
downloads
All versions This version
Views 6363
Downloads 101101
Data volume 313.4 GB313.4 GB
Unique views 5353
Unique downloads 2020

Share

Cite as