GeoTIFF to XYZ and CSV using QGIS

Step 1: Open the GeoTIFF File in QGIS

To begin, you need to open the GeoTIFF file that contains the topographic or bathymetric data. In QGIS, navigate to Layer > Add Layer > Add Raster Layer. Locate your TIFF file and click Open.

Step 2: Set the Projection

After adding the file, check the projection settings. Go to Properties of the layer and set the projection. This is essential for accurate data representation.

Step 3: Extract a Specific Area

If you wish to extract data from a specific area, use the raster extraction tool. Click on Raster > Extraction > Clip Raster by Extent. Input the minimum and maximum longitude and latitude for the area you want to extract. For example, to extract the Gulf of Mexico, set the coordinates accordingly.

Step 4: Export the Extracted Data as XYZ

Once you have clipped the desired area, you can export it as XYZ data. Go to Raster > Conversion > Translate (Convert format). Choose the clipped layer, set the projection again to be the same as the original raster data, and click on Save to File. Select the XYZ format from the options and save the file.

Step 5: Export as CSV

Alternatively, if you want to export the data as a CSV file, open the Processing Toolbox. Search for GDAL to XYZ, select your clipped layer, and then save it as a CSV file. This gives you flexibility depending on your needs.

FAQ

• What is GeoTIFF?
  GeoTIFF is a public domain metadata standard which allows georeferencing information to be embedded within a TIFF file.
• Can I use other GIS software for this process?
  Yes, the process is similar in other GIS software like ArcGIS.
• Where can I find Global Relief Data?
  You can download datasets from GEBCO data download.