QGIS tool to convert elevation values in a raster file from GNSS ellipsoidal heights to orthometric heights using a geoid grid file. Note: Horizontal coordinate system remains unchanged (input and output: EPSG:4326).
The tool is basically wrapping following gdalwarp command:
gdalwarp -s_srs "+proj=longlat +datum=WGS84 +no_def" ^
-t_srs "+proj=longlat +datum=WGS84 +no_defs +geoidgrids=<GEOGRID_FILE>" ^
-tr <X_CELL_SIZE> <Y_CELL_SIZE> <OVERWRITE> ^
<INPUT_RASTER> <OUTPUT_RASTER>And provides an interface to select:
| Parameter | Description |
|---|---|
<GEOGRID_FILE> |
file path to grid file |
<X_CELL_SIZE> |
x cell size of <INPUT_RASTER> |
<Y_CELL_SIZE> |
y cell size of <INPUT_RASTER> |
<OVERWRITE> |
adds -overwrite if given, i.e., force overwrite <OUTPUT_RASTER> |
<INPUT_RASTER> |
input raster |
<OUTPUT_RASTER> |
output raster |
- Download script file
elevation_conversion.py - Open Processing Toolbox panel (see menu Processing and then Toolbox)
- Click the dropdown in the panel's toolbar with the Python icon
- Select Add Script to Toolbox..., find script file and add it
- You then find the tool at the bottom of the tree under Scripts, Elevation Conversion and then Convert GNSS ellipsoidal heights to orthometric heights
Tested with QGIS 3.28.2 on Windows 10
Copyright (c) 2023 Dalhousie University
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
This tool requires PyQGIS, GdalAlgorithm and GdalUtils.