1. Load a frame from your video, or press Try it with our gate. 2. Click the 4 corner markers in order, going round. 3. Type the two side lengths. Your site file appears at the bottom.
loads our frame and our 4 real corners; press Undo to click them yourself
Click four points on the road surface, going round an area in one direction. With a tape, use the corners of the rectangle you measured. With a map, use four points you can also find on the map, spread over the crossing: zebra corners, kerb corners, lane-line ends.
Open a frame to begin.
Take a full frame of the video itself, not a screenshot with player bars:
ffmpeg -ss S -i VIDEO -frames:v 1 frame.jpg, with S the start of the site's window_s in
seconds (0 without one). The page scales it to the 640 px analysis size.
Optional, for the speed check (gate G6): after the four rectangle corners, click the four speed-line
tape marks, line A near kerb, line B near kerb, line B far kerb, line A far kerb, and give the taped distance between
the lines. The page writes trap from them, and check (line A to line B along the near kerb,
which the case agent asks a person to tape). SITE.json is empty at 5 to 7 points.
Open a screenshot of the same place from above, including the map's scale bar. Click the same four points in the same order (1 to 4), then the two ends of the scale bar (S1, S2).
Open a satellite screenshot.