I would like to use an aerial photo as a template for an HO layout but can’t figure out how far up I need to be so the print is to HO scale. How in the heck do I figure that out? Please help! I’m pulling my hair out over this and I don’t have much left to pull! I know it’s probably easy to figure out but I’m just not getting it. Thank you in advance and happy modeling!
Take a known distance/length of an object (distance between rails, etc.) and increase the image until the chosen object fits HO scale. For instance, if the photo is directly above the track, enlarge the image until it is the size of HO track. If the rail separation on the image is a scale 9 inches (use an HO-scale ruler), the photo needs to be enlarged 6.277777 times (56.5 inches divided by 9 inches).
Mark
If you’re an expert in optical engineering, and you know the characteristics of the lens used to take the photo, it’s a very simple mathmatical calculation.
If you’re like most of the rest of us, it’s a fairly mind boggling exercise. Camera lenses distort light that is passed through them, and you have to know HOW the lens is bending the light in order to reconstruct distance accurately. The previous poster is correct: measuring the size of a known object in the photo so that it is 1/87th of it’s actual size, it will be in HO scale.
But I have a more fundamental question: why are you trying to use an aerial photo as a template? Have you really thought it through? Most model railroads use a technique called “selective compression” in that most of the distances on our scale pikes are NOT strictly in scale. For instance, on my own Connecticut Valley RR, the distance between Old Saybrook and Haddam station is about 10 miles. That would consume 606 linear feet on a layout. The distance between them (around the corner) on my layout is about 12’. The YARD in Old Saybrook is modeled to scale, as is Haddam Station, but the distance between them is nowhere near right. Our scale trains also use much tighter turns and more angular turnouts than you would generally find on a prototype line.
Aerial photos are a great source of inspiration – but I would take it and build your own version of what you see rather than trying to use a template.
Got it! Some adjusting needed but very darn close depending on the ground elevation it’s 1:87 or 87 feet up. I was way over thinking this. Duh! Some spots need to be at 90’ if the rails are elevated for surface street traffic to flow. No problem though since it’s just for a template. Thanks for responding.
Thank you too for responding. Oh yes, I’m cutting the distance down on my layout. Some area’s around small town stops is what I’m using the aerials for. I wish I was rich beyond belief and had the money to buy a very large warehouse or old factory where I could build a replica of Indianapolis in HO scale. We were known as the wagon wheel of railroads where we had railroads that went N, S, E, W, NW, NE, SW and SE all of which met at one local, Union Station. Lots of different R.R. Companies and their holding and maintenance yards. Very efficient trolley system, an interurban electric system that reached most surrounding communities. In short, loads of railroading but unfortunately, the city paved over the trolley lines (they’re still there) and the railroads withered and died. Most of it is gone now but lives on in old aerial photos. The oldest is 1937. You can view these at http://imaps.indygov.org/prod/GeneralViewer/viewer.htm then on the bottom left where it says switch map set, the drop down above it go to aerial photography. Penn had a roundhouse that was almost complete circle to the east of Union Station. Check it out. It’s pretty neat.