How to calculate length of river segment?

[Remagen]

There is a feature at a certain place along the length of a river.  In describing it to others, I would like to say it is at River Mile___.  In other words, the distance of this feature from the mouth of the river.  I have found the latititude and longitude of the feature, and can find the latititude and longitude of the river mouth, but how to calculate the distance from mouth to feature taking into account meander, etc.?

 

Thanks.

[Nuclear Moose]

Use Google Earth to zoom in on the area and then use the linear measurement tool to follow the meander of the river until you reach your desired point and you will see GE returns the distance for you. You may have to set your desired units (meters, miles, feet etc.) in GE's preferences so your result is in the desired format.

[Nuclear Moose]

You could also do this in maps.google.com in MY MAPS and draw a path from A to B. You can then label and save that path and the length will be available as part of the information on that feature.

[Remagen]

Thanks very much for your reply.  I've tried what you suggested in your second note (using maps.google.com), and am running into a few problems.  First, I had to zoom in on the map to find the place to start.  Then I started making a line, but because of the scale of the zoomed-in image, had to keep zooming out to extend the line further downstream.  As I zoomed out, the river's course became less obvious because the view was further away, and the river feature became less distinct.  I was not able to figure out how to stay at the zoomed-in scale, and keep the line moving down-river because my cursor is doing the line making, and so can't be used to click-on and drag the map so I could move downstream.  Or at least I was not able to figure that out.

 

Suggestions?

[eastwest]

On the very bottom left of the map window (in regular Google Maps, not My Maps), you should see a small ruler icon. Click on that and start dropping points along the river. You should be able to drag the map in between clicking points to make new sections of the river visible.

If I were you, though, I'd take the results with a hefty grain of salt, because a) the differences between the points you've dropped and the map's river outline, small as each one may be, will add up, and b) the river outline on the map may not accurately reflect the water course in real life.

[eastwest]

Just to be clear, you need to be logged in for this tool to be available.

[eastwest]

 so can't be used to click-on and drag the map so I could move downstream.  Or at least I was not able to figure that out.

I just tried Craig's suggestion (creating a line in My Maps), and you CAN drag the map while dropping points. Here's what happens: when you click on a spot and release the mouse button, you create a new point along the line you're drawing. In between creating points along the river, when you click on a spot and move the mouse without releasing the button, you drag the map to a new spot. Then you release the mouse button (which does not create a point where you just left it) and can then go back to adding more points to the river.