How DO I Calculate Map scale to HO scale

[steinjr]

You also have to be carefull since topo maps show a lot of detail, but its not 100% accurate.  The exact positions of tracks, number of tracks, the arrangement of tracks and especially switches and crossovers cannot be reliably determined from a topo map of that scale.  I have been drooling over topo maps for the last 30 years and have used them extensively for research and have found that while an excellent resource, they are often "off" on some details  (building details, railroad details, piers, etc.)

Your best bet is to go to microsoft.terraserver.com and you can toggle between a topo map and an aerial photo.  Cross reference that with Google maps and you can get a really good representation of what the tracks were like within the last 5-10 years.  If you are really lucky you can even find some trains on the tracks and can even pick out car or engine types.

Dave H.

 Like here: http://tinyurl.com/yt77kn 

 This is a place called Corydon Junction in Indiana.'

 Click on "Road" to see map, and "Hybrid" to see satelite pix overlaid with map. 

 Observe that the map is claiming that North Street NE runs directly SW from the intersection with Corydon Junction Road and Trestle Road, but the satelite pix shows that it really runs in a different way.

 Observe that there is more RR tracks in the satelite pix than on the maps.

 Observe that you in the satelite pictures can see RR cars several places and even a full train if you follow the east-west mainline a little westwards.

 What Dave says above is very good advice.

 Other good web sites for satelite maps is http://maps.live.com and http://www.flashearth.com

 Grin,
 Stein

 

[dehusman]

You also have to be carefull since topo maps show a lot of detail, but its not 100% accurate.  The exact positions of tracks, number of tracks, the arrangement of tracks and especially switches and crossovers cannot be reliably determined from a topo map of that scale.  I have been drooling over topo maps for the last 30 years and have used them extensively for research and have found that while an excellent resource, they are often "off" on some details  (building details, railroad details, piers, etc.)

Your best bet is to go to microsoft.terraserver.com and you can toggle between a topo map and an aerial photo.  Cross reference that with Google maps and you can get a really good representation of what the tracks were like within the last 5-10 years.  If you are really lucky you can even find some trains on the tracks and can even pick out car or engine types.

Dave H.

[bearman]

The tilt was correct.  My guess is you are working off of a USGS topo map.  They do show a lot of detail and as noted, there will be a lot of compression involved depending on the amount of room you have for your layout.  You will also have to be careful about height as well.  If you are dealing with a mountainous region, for example, a difference in elevation of 500 real ft, not a terribly big mountain in my opinion, will result is a scale difference of 5.74 feet.

[steinjr]

 

Yes it is my mistake, it should be 62,500. These maps do have great detail.

So it will be 62500 divided by 12 = 5208.33 feet. 1 inch is just less than a mile.   

Thanks, Greg 

 Umm. 1 inch on the map is 62500 inches in reality, or 62500/12 = 5200 feet.

 A H0 scale representation of 5200 feet would be 5200/87.1 =  59 feet.

 So one inch on the map would be about 59 feet on the layout, when you work from an 1:62500 map, without compression.

 Quick conversion table:

 100 feet in reality = 1' 2" on layout
 300 feet in reality = 3' 5" on layout
 600 feet in reality = 6' 10" on layout
 900 feet in reality = 10' 4" on layout
1200 feet in reality = 13' 9" on layout

1200 feet is approximately 1/4 of a mile.

 Unless you have a big space for your layout, you probably will have to do quite a bit of selective compression.

 Smile,
 Stein

 

[pennsy1349]

 

Yes it is my mistake, it should be 62,500. These maps do have great detail.

So it will be 62500 divided by 12 = 5208.33 feet. 1 inch is just less than a mile.   

 

Thanks, Greg 

[tomikawaTT]

Bear w/me.

1 inch on the map = 625,000 actual inches or 52083.33 actual ft.  So, dividing the actual feet by 87 yields HO scale ft of 598.659 HO ft.

TILT!!!

1 FOOT on the map = 625,000 feet on the ground (118 miles plus).  Seems unlikely to show much.  Are you sure the scale isn't larger, say 1:62,500 (a common map scale)?

Then, 1 FOOT = 87.1 HO scale feet.

If you divide the map reduction scale by 87.1, you will get the factor by which you will have to enlarge the original to have it print out in HO scale.  Assuming 1:625000 is accurate, that means your one foot square map would have to be enlarged to be 7184 feet on a side - 1.36 full-scale miles!  1:62.500 would yield something that would have to be folded several times each way to fit inside the Rose Bowl.

Methinks some selective compression might be in order.

Chuck (modeling Central Japan in September, 1964)

[bearman]

Bear w/me.

1 inch on the map = 625,000 actual inches or 52083.33 actual ft.  So, dividing the actual feet by 87 yields HO scale ft of 598.659 HO ft.

[pennsy1349]

 

I am planning my layout and have come across a good technical map of the area I want to model.  But I am having trouble figuring out how to scale the map to HO.  The map scale reads 1 over 625000 scale.  So it means, one 6 hundreth and twenty five thousands, correct? 

I am trying to get the scale to HO so I can see where I need to trunkate the map and scale down the lines.   I would like to keep the terrain as close as possible, since it is an area thast goes up along the Susquehana river in PA.   The area has a lot of moountains and valley's where the train will hide and reappear.

 pennsy1349