[019] Global Mapper - Raster Layer

Today, we will cover the context menu for Raster Layers. Open your previous project and activate the 'Image' layer.

Let's look at the menus applicable to raster layers. You'll notice they are similar to those of elevation layers, but a few items are missing:

• Create Workspace File from Selected Layer(s)...
• EXPORT - Export Layer(s) to New File...
• MAP CATALOG - Add Selected Layer(s) to Map Catalog...
• BBOX/COVERAGES - Create Layer Coverage Box/Polygon Area Features
• Create Area Features from Equal Values...
• Vectorize Raster
• Link External Metadata File
• Save List of Layers to Text File...
• Set Background Color for Layer in Control Center

The usage is mostly the same as with elevation layers, so let's focus on Create Area Features from Equal Values... for images.

1. Create Area Features from Equal Values (Raster)

After selecting the layer and clicking OK, the setup screen appears. Here, you'll focus on Color Fuzziness instead of elevation.

• Maximum Match Distance: This indicates the range of color values (0–256) to be grouped into a single polygon.
  • 0: Separates polygons even if the color value changes by a single step (Exact match).
  • 256: Groups all colors in the entire range into one giant polygon.
  The higher the number, the larger the resulting polygon "chunks" will be.
• Select Color(s) to Create Areas For: Use this to isolate and vectorize only specific colors.

Once you click OK with these settings, an Image Areas layer is created, and you'll see small polygons generated on the main map.

2. Vectorizing a Specific Color

Now, let's learn how to create polygons for a specific color only. In the setup window, select Only Selected Color(s).

A color picker will appear. While you can choose from preset basic colors, clicking Pick Color from Map allows you to select a color directly from your current satellite image.

By increasing the Maximum Match Distance (e.g., to 40) and clicking OK, polygons will be generated only for the parts of the image that fall within that specific color range.

3. Vectorize Raster (Raster Setup)

The Vectorize Raster option for images is slightly different in its setup from the elevation version. I'll briefly explain the settings so you can try it yourself.

• Select Color(s): Choose the target color via the picker or the map.
• Matching: Determines the inclusion range based on the selected color. Moving the slider toward Exact narrows the range, while moving it toward Fuzzy broadens it.
• Color Matching Preview: Shows a preview of the result. However, the preview window is often too small to be truly useful.

This concludes our exploration of the Raster Layer context menu.

That's all for today~

Next, we will look into the context menu for Point Layers.