Digital Elevation Model (DEM) Processing
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# [[Exercise 01: First steps in QGIS|Add]] the raster layers ''N51E009.hgt'' and ''N51E010.hgt'' to a new [[QGIS]] project (from ''geodata\raster\DEM'', see [[Course data]]). Arrange the first above the latter layer. | # [[Exercise 01: First steps in QGIS|Add]] the raster layers ''N51E009.hgt'' and ''N51E010.hgt'' to a new [[QGIS]] project (from ''geodata\raster\DEM'', see [[Course data]]). Arrange the first above the latter layer. | ||
# Merging layers | # Merging layers | ||
− | #* Select {{mitem|text=Raster --> Miscellaneous --> Merge}}. In the appearing menu, click the {{button|text=Select}} | + | #* Select {{mitem|text=Raster --> Miscellaneous --> Merge}}. In the appearing menu, click the {{button|text=Select}} beside the {{button|text=Input files}} field. Browse for the maps ''N51E009.hgt'' and ''N51E010.hgt'' and select both (by clicking with pressed {{button|text=Ctrl}} key) (figure '''A'''). |
#* Select an output directory and file name (e.g. ''N510_merged'') under {{button|text=Output file}}. Confirm with {{mitem|text=OK}}. | #* Select an output directory and file name (e.g. ''N510_merged'') under {{button|text=Output file}}. Confirm with {{mitem|text=OK}}. | ||
# Reprojecting layers (warp) | # Reprojecting layers (warp) | ||
#* Select {{mitem|text=Raster --> Projections --> Warp (reprojects)}}. | #* Select {{mitem|text=Raster --> Projections --> Warp (reprojects)}}. | ||
#* As {{button|text=Input file}} choose the merged layer from the preceding step. Select an according path and file name for {{button|text=Output file}}. | #* As {{button|text=Input file}} choose the merged layer from the preceding step. Select an according path and file name for {{button|text=Output file}}. | ||
− | #* Determine the correct source and target coordinate system ({{button|text=Source SRS}} and {{button|text=Target SRS}} -- The coordinate system of the source layer is WGS84 (EPSG:4326). Use UTM32 (EPSG:32632) as target. | + | #* Determine the correct source and target coordinate system ({{button|text=Source SRS}} and {{button|text=Target SRS}}) -- The coordinate system of the source layer is WGS84 (EPSG:4326). Use UTM32 (EPSG:32632) as target. |
− | #* Confirm with {{button|text=OK}}. | + | #* Confirm with {{button|text=OK}}. |
+ | |||
+ | [[file:RemSens_Exercise05_01.png|thumb|left|450px|'''Figure A:''' Merge dialogue and file browser in [[QGIS]] 2.0]] | ||
==Clipping and Resampling of DEM data== | ==Clipping and Resampling of DEM data== |
Revision as of 10:35, 21 January 2014
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This section is still under construction! This article was last modified on 01/21/2014. If you have comments please use the Discussion page or contribute to the article! |
- This article is part of the QGIS tutorial 2013/14.
In this article you will learn how to pre-process and enhance digital elevation model (DEM) data, as well as how to create a 3D-Model
Loading, merging and reprojection of DEM data
- Add the raster layers N51E009.hgt and N51E010.hgt to a new QGIS project (from geodata\raster\DEM, see Course data). Arrange the first above the latter layer.
- Merging layers
- Select Raster --> Miscellaneous --> Merge. In the appearing menu, click the Select beside the Input files field. Browse for the maps N51E009.hgt and N51E010.hgt and select both (by clicking with pressed Ctrl key) (figure A).
- Select an output directory and file name (e.g. N510_merged) under Output file. Confirm with OK.
- Reprojecting layers (warp)
- Select Raster --> Projections --> Warp (reprojects).
- As Input file choose the merged layer from the preceding step. Select an according path and file name for Output file.
- Determine the correct source and target coordinate system (Source SRS and Target SRS) -- The coordinate system of the source layer is WGS84 (EPSG:4326). Use UTM32 (EPSG:32632) as target.
- Confirm with OK.
Clipping and Resampling of DEM data
- Create a boundary polygon