Map Backgrounds and Terrain
This task allows you to download more backgrounds and terrain to your site.
Map Backgrounds
Import a georeferenced image | For importing image files that contain georeferenced meta-data (i.e. they have a location and area). They will be placed in the correct location on the map | |
Import and rectify any image | For importing image files that do not contain any georeferenced information (i.e. a simple *.jpg or *.png file). The rectification tool appears to allow you to position the image on the map (see below). | |
Download imagery | Download imagery from various online sources. |
Rectification Tool
This tool allows you use a non-georeferenced image as a background image on the map. This is useful if you receive an image or PDF of the site layout that doesn't have any geographic reference. You can then use this rectified site layout image to help you lay out an existing site layout.
The idea is to add control points to the source image and add corresponding control points on the map (which will have a geographic position) using the downloaded background imagery as a reference. The software then warps (rectifies) the bitmap image by lining up the corresponding control points and stores the warped image as a background image.
To use it:
- Open a source bitmap image. This appears on the top-left of the tool window.
- Pan and zoom the workbook map (on the top-right of the tool window) to roughly show the same area covered by the source bitmap.
- Right-click on the source image to add a control point. A corresponding control point appears in the workbook map.
- Select and drag the corresponding point in the workbook map to the correct geographic location.
- Add at least 3 controls points to help get the rectification correct.
- Click the 'Rectify' button. The image will be rectified and added as a background image to the map.
Terrain
Import a terrain file | If you have been provided with a specific elevation file for your site you can import it here. | |
Download terrain | This shows the download wizard where you can download free SRTM (Shuttle Radar Topography Mission) terrain for the selected area. This is generally lower resolution than bought terrain files for your area, but often sufficient. |