Obstacles between camera and subject come in primarily three forms:
- Natural - Ground (i.e. the earth itself)
- Natural - Above Ground (e.g. trees)
- Man-made (e.g. buildings)
We always encourage a scouting trip for any important locations or occasions - you can't beat the insights you'll gain from getting out to location and checking it out in person.
That said, there are a number of tools in Photo Ephemeris Web that can help.
Photo Ephemeris Web allows you to determine if the ground is going to obstruct your view. To do this, use the Geodetics tool. You can find out more about using this tool here:
Using TPE Desktop Web App, Part 3: Geodetics
The app checks elevation differences between the red and grey pin and can calculate the angle of view. These tools are best used in conjunction with the Terrain map style, so you can use the contours and shading to judge where hills may obstruct the view, and then check with the geodetics tool.
For example, you might want to know if you can see the town of Grundarfjö∂ur from the east side of Kirkjufell:
The Terrain map already shows that the answer is almost certainly no, but with the geodetics tool, you can confirm this. In the screenshot above, the information at the lower left of the map shows the angle of altitude between red and grey pin ("Elevation angle -0.02°").
Setting the grey secondary map pin to the top of Kirkjufell, gives the altitude as "+8.95°". As 8.95° is greater than -0.04°, there is no clear sightline from red to grey pin.
Note: If you require more advanced sightline analysis, please consider using the sightline tool in our iOS app.
Man-made obstructions and trees
The elevation data that Photo Ephemeris uses does not account for man-made and above-ground natural obstructions. Geodetics will not tell you if the sightline is blocked by either of these. However, in cases where your camera position is located next to a road, you may be able to use Google StreetView to check the sightline without having to scout the location in person (requires PRO subscription).
Continuing with the example above, drag and drop the StreetView person icon to the point you want to check (valid locations are highlighted in blue while dragging):
As you drag and drop, locations where Street View is available are highlighted in Blue on the map. In this, case StreetView doesn't cover our original Grey pin position, but it does cover the red pin. Here's the view from the red pin - it's pretty clear that the grey pin is obstructed:
Of course, you can use this to check buildings and trees also. For example, what is visible from Centre Drive in Central Park looking South?
To exit Street View, click the 'back' arrow at the top left of the map.
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