QGIS is a free and open source GIS software which you can install on Windows, MacOS, Linux, and BSD. You can add Planets’ GeoTIFFs by dragging them into QGIS layer or map view. QGIS will automatically recognize the imagery and locate them properly without any additional input.
You can open the image properties by double-click on the layer and here are some examples of what you can do within layer properties:
- View Information such as the coordinate reference system (CRS), extent, unit, compression method, etc.
- Under Symbology tab, you can change the band configuration to suit your needs.
- You can view the distribution of the bands or colors in your raster in Histogram tab. The histogram is generated when you click the Compute Histogram button.
For more QGIS related, you can explore their documentation.