DOI: 10.23729/cf81f7f3-faaa-4729-aa1c-aa4dd38951aa
title: LiPheStream - A 18-month spatiotemporal point cloud time series of Boreal trees from Hyytiälä, Finland

description: The LiPheStream dataset is a 18-month-long point cloud time series comprising LiDAR point cloud data at 103 time points for 458 individual trees of three boreal species (silver birch (Betula pendula Roth.), Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies H. Karst.)). The dataset was collected using the Finnish Geospatial Institute (FGI) Lidar Phenology station (LiPhe) between April 2020 and September 2021 and is placed in the folder "LiPheStream". Wintertime data between January and February in 2021 is provided in a separate folder, "LiPheStream_Winter".

The dataset is comprised of georeferenced individual tree point clouds containing 3D georeferenced coordinates (EPSG: 3067 – ETRS89/ TM35FIN), points return number (scalar from 1 to 15), number of returns (scalar from 1 to 15), intensity as amplitude, scan angles (theta and phi in degrees), reflectance (dB), return pulse deviation (measure of pulse shape distortion) and range (m).

LiPheStream includes the single tree time series as compressed to one zip file per tree, ordered after species (scots_pine (1), norway_spruce (2), silver_birch (3), and unidentified (4)) and quality class of the majority of time points per tree (ranging from 0-bad to 4-good). The zip-filename denotes the tree id. The single tree point cloud filenames include date and time (YYMMDD_HHMMSS) , treeID and Quality class : 'YYMMDD_HHMMSS_treeID_Species_Quality.laz'.

The individual tree segmentation in LiPheStream is generated with a fully automated pipeline and may contain errors. The individual tree quality class is determined based on the quality class of the majority of time points within the time series. Thus, trees in any non-zero quality class folders may include time points with different quality data or incorrect tree identification. Tree identification correctness can be reviewed using the provided tree attribute table. Trees with quality class zero were not detected robustly with the fine segmentation routine. However, the trees in this class can have high quality coarse segmentation and overall these time points include the tree point cloud and its neighborhood. We recommend users to analyze these time points visually to verify the point cloud suitability. Please contact the authors in case of any errors. Additional data can be provided upon request.

The LiPheStream dataset also includes additional data: 
- Five full scan area point clouds at the folder "full_area_overview" : 
 - Two full resolution point clouds from 06 April 2020 ("leaf off") and from 15 July 2020 ("leaf on")
 - Two preprocessed resampled point clouds from 06 April 2020 ("leaf off") and from 15 July 2020 ("leaf on")
 - One ALS point cloud from 11 August 2021 called "Hyytiala_HeliALS-TW_1550nm_20210811_Classified_Same_StemMap_200m.laz"

- TreeAttributes.csv: Tree attributes and location estimated from the first point cloud in the timeseries on 06 April 2020 

For further information about the processing steps, please refer to LiPheKit: https://gitlab.com/fgi_nls/public/liphekit

LiPheKit SampleData includes (provided in folders that can directly be used to run LiPheKit: 
- LiPhe_polygon.gpkg: A polygon covering the whole area of LiPheStream tree locations 
- DTM_20cm.las: Digital Terrain Model for the LiPhe area
- 200406_100502_Sample.laz: Downsampled point cloud from 06 April 2020 at 10:05 EET with 5 cm resolution cut from the scan area 

LiPheStream_Catalog:
- single tree geojson files collecting the full single tree timeseries metadata, for initial queries.