Calculating Visibility from Riga, Latvia

In the map above, I used GRASS 6.4.1 to calculate visibility from the ocean near Riga.  I used coordiates 24.10, 57.07 in the projection and I set the range to 5 X 10 (6) Meters.  The result is based on the elevation file and shows a thin line of red dots along the shoreline and on a neighboring island.  This theoretically means that an observer standing at the point that the road runs perpendicular to the Ocean will find visibility to the shoreline and the ocean, but not much on shore.  This is only an experiment and I am not sure of the results; there may be an error here.

In my choice of x,y coordinate, I picked one at random and I am not sure if it is in the City of Riga and the height of the elevation of the observer is 1.5 meters or the height of a person  A more interesting perspective would be a calculation from a point of interest, such as the top of the railroad bridge near 13 Janvara iela or other point.  If someone has a nice point of interest to calculate visibility from Riga, I will nead the x, y coordinate and the height in meters.

Example:  Freedom Monument, 42 Meters High, 56" 57,  24"4.

Regards,
Tramway Null(0)