Learn how to import high-resolution satellite and aerial imagery along a corridor in AutoCAD/Civil 3D using Plex-Earth’s Imagery Mosaic workflow with the By Route option. This tutorial explains how to define a route-based cover area by selecting a polyline path and setting a corridor swath width, then choose an imagery source and resolution to create a focused basemap only along the alignment. It also includes optional steps for importing 3D terrain along the same corridor and draping imagery onto terrain for improved 3D route visualization.
Create a corridor basemap in AutoCAD/Civil 3D by importing high-resolution imagery along a route with Plex-Earth.
Introduction
If you're working on a linear project such as a road, railway, pipeline, bridge, transmission line, or corridor study, importing imagery and terrain for the entire site area can be unnecessary and time-consuming. With Plex-Earth, you can model the real-world environment along a route by importing satellite/aerial imagery and 3D terrain only for a corridor that follows your alignment.
Usually, when importing imagery by selecting a rectangular area, like for the road project below, Plex-Earth will generate tiles for the whole area, even though many of them might not be useful. For example, it will import 81 tiles (for Zoom Level 19) in order to cover the totality of the north/southbound road.
Luckily, Plex-Earth has got you covered! With the By Route option from the Create Mosaic feature of Plex-Earth, the tiles required will be greatly reduced to almost half.
This tutorial will present the way this can be done.
Before You Start
Before importing imagery, make sure your drawing is georeferenced, so Plex-Earth can place the imagery in the correct real-world location.
There should be an existing route object in your drawing, such as a polyline representing the path/alignment/centerline of the corridor.
Step 1. Create Mosaic Command
Go to the Plex-Earth ribbon → Contextual Data panel → Create Imagery drop-down menu → Create Mosaic, as shown in the screenshot below. Alternatively, type in PXV_IMAGERY_MOSAIC in the command line.
Step 2. Define the Cover Area Using By Route
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Click on the By Route option.
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Select the respective polyline.
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Define the corridor’s swath width → Accept. Take note that the swath width refers to the width of the whole corridor.
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A palette will show up, usually located on the left side of your screen or undocked, to confirm the area. To continue, click on Next: Select Imagery Type. Alternatively, you can choose to specify another area or completely close this command.
Step 3. Select Imagery Source: Select Provider and Dataset
Step 3a. Select Provider
Select your preferred provider and click Next. Choose from the several providers available, including Custom Maps. Basic providers such as Google Maps and Azure Maps are some of the included options, but depending on the area, premium imagery providers, like Nearmap, will also show up as options.
Step 3b. Select Dataset
Select the preferred dataset from the available options, if any. For Google Maps, for example, you can choose among Satellite, Roads, Hybrid Satellite, and Terrain. Then, click on Next.
Step 4. Select Resolution and Tile Selection
Choose your resolution. You can choose between medium resolution, high resolution, very high resolution, and ultra high-resolution options.
You can proceed with fetching the imagery by clicking Accept.
By default, the Edit tile selection box is unticked and will fetch all the tiles of the mosaic. You can also tick the Edit tile selection box to choose the tiles you want to fetch. This will prompt you to choose the tiles you prefer for your drawing.
The result is a high-quality basemap imported only along the corridor, instead of covering a full rectangular area.
Optional: Import Terrain Along the Same Corridor
If you also want elevation/topographic context along the route, you can create terrain for the same corridor area:
Go to the Plex-Earth ribbon → Create Terrain → By Route.
Select the same route polyline.
Enter the same corridor swath width.
Choose the terrain output type (contours, mesh, points, Civil 3D surface, or advanced terrain model). Choose the mesh or advanced terrain model if you want to create 3D imagery or drape the imagery onto the terrain.
Optional: Drape Imagery onto Terrain (3D Visualization)
Choose the mesh or advanced terrain model when selecting the surface type for the terrain model.
- For the advanced terrain model, go to the Terrain Editor → Tools → Drape Image. Choose the imagery mosaic imported.
- For mesh: Insert a raster image for the imagery imported, like in this tutorial. Then, go to the Plex-Earth ribbon → Raster Tools panel → Import World File dropdown menu → Drape Image on Mesh. Select the raster image, then the mesh.
For more information on draping an image on terrain, check out this tutorial: Drape Image to Terrain
FAQs
What is the swath width and how do I choose the right value?
The swath width is the total width of the corridor area measured perpendicularly from the route centerline. For example, a swath width of 200m means 100m on each side of the alignment. Choose a value that covers all the area relevant to your project, such as the road right-of-way, adjacent terrain, or surrounding context. A wider swath means more tiles and longer fetch time, so keep it as narrow as your workflow allows.
Do I need an existing polyline in my drawing before I start?
Yes — the By Route method requires an existing polyline in your drawing that represents the route centerline or alignment. Make sure your road, railway, pipeline, or path is already drawn as a polyline before running the Create Mosaic command. If you don't have one yet, draw it first or import/copy it from Google Earth.
Why use By Route instead of just drawing a rectangle around my project?
For linear projects, a rectangular import covers a large area including parts you don't need, resulting in significantly more tiles — for example, 81 tiles vs around 45 for the same road using By Route. Fewer tiles means faster fetch times, lower resource usage, and a cleaner drawing. By Route clips the mosaic to follow the alignment, so you only import what's actually useful.
Can I also import terrain along the same corridor?
Yes!. After importing imagery, go to Create Terrain → By Route in the Plex-Earth ribbon, select the same polyline, and enter the same swath width. You can then choose your terrain output type. If you want a 3D visualization, select the mesh or advanced terrain model option and use the Drape Image tool to overlay your corridor imagery onto the terrain surface. See Drape Image to Terrain for the full workflow.
Related Questions
This article explains how to import satellite and aerial imagery along a route or corridor in AutoCAD or Civil 3D using Plex-Earth. You may have searched for:
- How to import imagery along a road, railway, or pipeline in AutoCAD
- How to get a satellite basemap for a linear project or alignment
- How to import imagery for a road or highway corridor in Civil 3D
- How to reduce the number of tiles when importing imagery for a route
- How to combine imagery and terrain for a corridor project in CAD