PhotoOverlay view
From SnapMap
A PhotoOverlay view is a type of view tag, taking its name from the feature of Google Earth which records, more or less, the complete geometry for a photograph. It includes data for location (latitude, longitude and altitude), orientation (compass heading, elevation and roll), field of view, and crop.
To use a PhotoOverlay view in SnapMap, a photograph’s position is set up in Google Earth as a PhotoOverlay, then its KML is copied and pasted in as a view tag. SnapMap then parses the KML to work out how the photograph is positioned.
PhotoOverlay views have the tag predicate view.
PhotoOverlay views are recommended for oblique aerial photos.
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Step-by-step guide
- Ensure there’s a copy of the photo being tagged on your local disk.
- On a SnapMap image page, from the view selector choose PhotoOverlay view and click Add view.
- Start Google Earth.
- Navigate so that the area in the photograph is, very roughly, in the Google Earth view.
- From the menu select Add, Photo.
- In the New PhotoOverlay panel, click Browse... and find the photo.
- Ensure the Photo tab is active in the panel.
- Using your skill and judgement, adjust the view until it matches the photo.
- Click OK to save your PhotoOverlay temporarily in Google Earth’s Places panel.
- Right-click on the PhotoOverlay in the Places panel, and choose Copy.
- Return to SnapMap and paste the contents of the clipboard into the text box.
- Click Add tag. That’s it!
Tips
- You can use the normal Google Earth navigation controls, as well as the controls in the PhotoOverlay panel.
- Use the Transparency control, scrubbing it left and right, to compare photo and Google Earth.
- Pay due respect to the field of view controls.
- Keep the Altidude control on "above ground".
- In a twin-monitor setup, it’s handy to keep the PhotoOverlay panel and the main Google Earth window on separate monitors.
- If you want to adjust an existing PhotoOverlay in Google Earth, you can right-click and choose Get info.
- To avoid confusion when creating views for several photos at once, give each PhotoOverlay a name.
- Delete the PhotoOverlays within Google Earth after they are safely recorded as SnapMap tags.
