Purpose and Utility

In CAD drawings, working with multiple georeferenced image tiles — especially after using tools like Download Web Map Tiles — can quickly overload your file, increase size, and slow down performance. That’s where mosaicking becomes essential.

The Mosaic Images tool helps you merge multiple image tiles into a single raster. This process not only reduces clutter but also improves the manageability and portability of your DWG. It’s the recommended next step after importing tiles — a cleaner, safer option that ensures your drawing remains optimized and organized.

Technical Description

• Input Requirement: One or more georeferenced raster images (e.g., .png with associated .pgw files) must already be present in the drawing.
• Image Selection:
  • You can select all images at once or choose selectively which ones to mosaic.
  • Images are listed with filenames — users can pick and arrange them as needed.
• Ordering Control:
  • The stacking order of images in the mosaic matters (especially if some tiles overlap).
  • Use Move Up and Move Down buttons to change the order.
  • First, select an image in the list, then press the movement buttons.
• Output Folder:
  • After confirming the order, the user is prompted to specify an output folder where the mosaic image will be saved.
  • SPCAD then begins the mosaicking process.
• Process Handling:
  • The tool merges the selected images into a single raster image, ensuring georeferencing is preserved.
  • Heavier images may take longer to process.
  • The user can cancel the operation at any point before completion.
• Post-Mosaic Cleanup:
  • After successful mosaicking, you can detach the individual image tiles from the drawing to reduce load.

Workflow

1. Go to Coordinate System → GeoTools → Mosaic Images, or type MOSAIC_SP
2. Ensure required tiles are already loaded in the drawing (e.g., from Download Web Map Tiles)

3. Select images you wish to include:
   • Choose all, or be selective
   • Use Move Up / Move Down to define image order
4. Click OK once image list and order are finalized
5. Specify the output folder where the final mosaicked image will be saved
6. Wait for processing — time depends on image sizes

3. Detach old tiles if needed to keep your drawing lightweight

Tips & Notes

1. Why Mosaicking Helps:
   • Keeps your DWG file clean and less cluttered
   • Makes image management simpler (only one image to track)
   • Prevents accidental shifting or deletion of individual tiles
2. You can run this tool multiple times if your images are from different areas or resolutions
3. Combine with Cartographic Grid for layout preparation