Eliminating Noticeable Pixelated Squares Raster Map in QGIS

 To eliminate the noticeable pixelated squares in your raster map, such as those seen in image 'Before' on the left hand side, and achieve a smooth, continuous color transition as seen in image 'After' to the right hand side, you need to adjust the Resampling method in the layer's properties.

By default, QGIS often uses 'Nearest Neighbour' resampling for speed, which preserves the hard edges of pixels. To blend them, you must switch to an interpolative method like Bilinear or Cubic.

Here is the step-by-step process in QGIS:

1. Open Layer Properties: Double-click on your raster layer (the one showing the blue squares within the red boundary) in the Layers panel. Alternatively, right-click the layer and select Properties.

2. Navigate to the Symbology Tab: In the Properties window, click on the Symbology tab (usually the second icon on the left).

3. Locate Resampling Settings: Scroll down within the Symbology tab to find the section labeled Resampling. It is often collapsed; you may need to click the arrow next to it to expand the options.

4. Adjust Zoomed In and Zoomed Out Methods: You will see two dropdown menus:

   • Zoomed in: Controls how pixels are displayed when you are zoomed very close to the raster.

   • Zoomed out: Controls how pixels are displayed when you are zoomed out far.

5. Change the Method: For both dropdown menus, change the setting from Nearest Neighbour to either Bilinear or Cubic.

   • Bilinear: Calculates the value of a new pixel by averaging the four nearest pixel centers. This provides good smoothing.

   • Cubic: Uses a slightly more complex calculation (averaging the 16 nearest pixels), which often yields a slightly sharper, yet still smooth, result.

   • Recommendation: Try Cubic first for a high-quality smooth look.

6. Apply and View: Click Apply and then OK to close the Properties window.

Your map canvas will immediately update. The sharp, blocky pixel edges seen in 'Before image' will be blended together, creating a smooth, continuous gradient of colors.

Note: This process changes how QGIS displays the raster data, not the underlying data file itself. If you export the map at this stage, the smoothness will be preserved.

Thank you.