Heatmap-no data vs Zero

Question

I am new to QGIS. I am working on creating heat map of bird diversity(data downloaded from ebird.org). The issue I face is that how to differentiate between:

1. There areas where data is not available (bird surveys haven't happened)
2. Bird survey has happened but a particular bird species is absent at that area

When create a heatmap of the particular bird species with QGIS 3.2.3(windows), the map interprets both situations as same, which is not correct. In the image attached, the white areas are either with no data or places where there are no kingfishers found. I want to color code them differently.

How can I find a way to overcome this?

Answer 1

The approach that you can take is to either assign a different value within the attribute table from 1 to either category to allow you to distinguish between the scenarios you've mentioned. Or you can select the feature of interest and create a new dataset and now you will have two different datasets which you can stylize and categorize independently.

Answer 2

I would take the approach that the EBird range map does - use a color to indicate where a checklist was submitted, but no sighting of the species, and use no color to indicate where no checklists/no species were seen:

So in your case, I would keep the white to indicate ZERO, but would fill in the other areas in your density raster with a grey color to indicate 'no data submitted' or something to that effect.