Dataset: Estonia

Published: 6 July 2021| Version 2 | DOI: 10.17632/svp3xmmt23.2
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Description

This dataset presents the DTW digital map for an area of interest in Estonia, bounded by points. Area: 150 km^2. Reference coordinate system: WGS EPSG 4326. Coordinates: Point 1 X 26.892116; Y 59.168692; Point 2 X 26.891690; Y 59.303397; Point 3 X 26.716087; Y 59.303132; Point 4 X 26.717204; Y 59.168429. Changelog: 1. Added Fire Ponds Allocation. Results will be presented at The 2nd International Electronic Conference on Forests — Sustainable Forests: Ecology, Management, Products and Trade (IECF2021), 01.09.2021, online.

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Steps to reproduce

We used a digital elevation model (DTM) with a one-meter raster cell resolution provided by the Estonian Land Board as input data [1]. We used the following processing order for DTW map generation: 1. Fill sinks in a surface raster to remove minor imperfections in the DTM data. 2. Create a raster of flow direction according to 8 directions whose values correspond to the sides of the world (1 - E, 4 - SE, 8 - S, 16 - SW, 32 - W, 64 - NW, 128 - N) from each DTM cell to the neighbouring ones down the slope [2, 3]. 3. Creates a raster of accumulated flow into each cell as a weighted sum of all cells whose flow enters each cell down the slope [4]. 4. Identify the thalwegs by establishing the minimum threshold value of accumulated flow corresponding to streams (≥ 5000 m2) [4, 5]. 5. Determine the slope (gradient or steepness) in degrees for each cell of the DTM raster surface [4, 5]. 6. Convert the slope in degrees to m/m (rise/run) by adding a tiny constant (0.001) to all values [4]. Using the formula: tan B * 180 + 0.001, where B – slope, degrees. 7. Run the Cost Distance function to calculate the DTW index. Input source locations are the thalwegs [5] identified at step 4. A raster determining the total cost of movement through each cell – slope raster in m/m (rise/run) with a very small constant (0.001) added to all values. References 1. Elevation Data Geoportal Available online: URL: https://geoportaal.maaamet.ee/eng/Spatial-Data/Elevation-data-p308.html (Accessed on 06.05.2021) 2. Greenlee, D. D. 1987. "Raster and Vector Processing for Scanned Linework." Photogrammetric Engineering and Remote Sensing 53 (10): 1383–1387. 3. Jenson, S. K., and J. O. Domingue. 1988. "Extracting Topographic Structure from Digital Elevation Data for Geographic Information System Analysis." Photogrammetric Engineering and Remote Sensing 54 (11): 1593–1600. 4. Tarboton, D. G., R. L. Bras, and I. Rodriguez–Iturbe. 1991. On the Extraction of Channel Networks from Digital Elevation Data. Hydrological Processes, 5, 81-100 5. Shihov, A.N., Cherepanova, E.S., Ponomarchuk, A.I. Geoinformation systems: usage of GIS-technologies for hydrological tasks: handbook. Perm State National Research University: Perm, 2014. 91 p. (in Russian)