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Geographic Information Systems (GIS) allow us to turn raw data into meaningful visual maps. If you're working with a CSV file containing latitude, longitude, and land cover category data (e.g., Built-up, Forest, Wetland), QGIS is a powerful and free tool for this task.

In this tutorial, we'll guide you step-by-step to create a categorically styled distribution map in QGIS — just like those seen in scientific publications.

🗂️ What You'll Need

• QGIS (v3.x or later)

• A CSV file with at least these columns:

  • Latitude

  • Longitude

  • Category_name (or similar)

Example row from your CSV:

Latitude,Longitude,Category_name
23.525432,92.247847,Built-up

📌 Step 1: Load Your CSV as a Point Layer

1. Open QGIS.

2. Go to Layer → Add Layer → Add Delimited Text Layer.

3. Browse and select your CSV file.

4. Set:

   • X field → Longitude

   • Y field → Latitude

   • Geometry CRS → EPSG:4326 (WGS 84)

5. Click Add → Your points should now appear on the map.

🎨 Step 2: Categorize by Land Use Type

1. In the Layers Panel, right-click on your new layer → Properties.

2. Go to the Symbology tab.

3. Change the renderer type to Categorized.

4. In the Value field, select Category_name (or whatever your category column is named).

5. Click Classify. This will generate color symbols for each unique category.

⚠️ If only one symbol appears, your data may have whitespace or case issues. Clean the CSV using a spreadsheet editor or a Python script that strips trailing spaces.

🎯 Step 3: Assign Custom Colors (Optional)

To match a specific legend (e.g., red for built-up, green for forest):

1. In the Symbology panel, double-click the color box next to each category.

2. Manually choose the color you want.

3. Use the same RGB codes from your project or publication.

Example color scheme:

🧭 Step 4: Add a Basemap (Optional)

1. Go to the Browser Panel.

2. Under XYZ Tiles, right-click and add OpenStreetMap or Esri World Imagery.

3. Drag the tile layer below your point layer in the Layers Panel.

🧭 Step 5: Add a North Arrow and Scale Bar

1. Go to Project → New Print Layout.

2. Add your map to the layout with the Add Map tool.

3. Use the Add North Arrow and Add Scale Bar tools from the top toolbar.

4. You can adjust placement, size, and style from the right panel.

📤 Step 6: Export the Final Map

1. In the Print Layout, go to Layout → Export as Image or Export as PDF.

2. Choose resolution (300 dpi for publication-quality).

3. Save the file.