Hi guys. I finally got around to having ago with Transdem and have made boards suitable for my needs. What I want to know is that now I know where the route of the track is to be, how do I know what the track height is meant to be at a given point? Is there a way of me being able to find these heights and to transfer them to my new route? Obviously at the moment it just follows the contours of the hills rather than creating embankments, cuttings and tunnels etc.
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Transdem and track heights
- Thread starter AntonyVW
- Start date
JackDownUnder
Well-known member
Did you not draw your track over the map lines with a poly line in TranzDem?? then export seperate from the map tiles.
I find that one still has to make adjustments to track height along the route to suit the embankments, cuttings and tunnels.
After a lot of trial and error I work from one end where i am able to confirm the starting track height.
I add spline points at appropriate positions in the track created by TransDem one at a time from the start point, leave the first section then progressively delete as one progresses.
At each spline point measure the height, then apply it to fix its height.
Assess whether the route is on an embankment or in a cutting and adjust the spline heights progressively.
I do not worry about the curves, letting the route spline make them as the route progresses. only add spline points at on the curves where necessary to bring the track back into alignment with the mapping.
What I have also learned is not to be too peddantic about the Route being 100% accurate, as long as it follows the route.
There are not enough features in the game to model the route as it exists or existed, so compromise is neccessary, especially if one does not know how to build the required models.
I have a lot of work to do yet to determine loco shed allocations, freight movements, and type of running gear.
Don't forget the era I am doing was the time when most goods were moved between centres by rail.
My current route is set predominately in West & North Yorkshire in the pre Beeching era, 1900 to 1954.
I am currently adding yards and sidings from old maps most of which are available from the North Yorkshire Council web site http://maps.northyorks.gov.uk/connect/?mapcfg=historic_maps.
I find that one still has to make adjustments to track height along the route to suit the embankments, cuttings and tunnels.
After a lot of trial and error I work from one end where i am able to confirm the starting track height.
I add spline points at appropriate positions in the track created by TransDem one at a time from the start point, leave the first section then progressively delete as one progresses.
At each spline point measure the height, then apply it to fix its height.
Assess whether the route is on an embankment or in a cutting and adjust the spline heights progressively.
I do not worry about the curves, letting the route spline make them as the route progresses. only add spline points at on the curves where necessary to bring the track back into alignment with the mapping.
What I have also learned is not to be too peddantic about the Route being 100% accurate, as long as it follows the route.
There are not enough features in the game to model the route as it exists or existed, so compromise is neccessary, especially if one does not know how to build the required models.
I have a lot of work to do yet to determine loco shed allocations, freight movements, and type of running gear.
Don't forget the era I am doing was the time when most goods were moved between centres by rail.
My current route is set predominately in West & North Yorkshire in the pre Beeching era, 1900 to 1954.
I am currently adding yards and sidings from old maps most of which are available from the North Yorkshire Council web site http://maps.northyorks.gov.uk/connect/?mapcfg=historic_maps.
steamboateng
New member
If you can find contour maps of the area, elevation points wil be marked on the route right of way. I believe Google Earth data may also help to establish elevations along the routel
I don't know what source you used for the downloaded DEM data, but keep in mind that the resolution of the DEM data will affect the accuracy of the TransDem model.
I don't know what source you used for the downloaded DEM data, but keep in mind that the resolution of the DEM data will affect the accuracy of the TransDem model.
Thanks guys for the support. The first time I exported I just did the dems, however I have since done a second export where I did export the track as well as the dem which is why I know that the track heights were wrong. They just followed the contours of the hills rather than the actual track heights. I have since realized that neither program is capable of doing what I had hoped, but I do intend to figure it out. What I needed was where to find these heights which steamboating has pointed me in the right direction. I did note JackDownUnder that from the produced map that Transdem adds rather more spline points than is necessary, in some cases overlapping each other for no apparent reason. So your suggestion to only put them where needed makes a lot of sense. Now all I need to do is dig out my original map and find those elevation points along the right of way. Thanks guys again.
A quick (hopefully) question regarding elevation heights on the maps. Im looking at an old map of a section of track. Next to it it has 2 numbers - one above the other with an arrow pointing to the center point between the 2 tracks. I presume that this is the elevation for that point? If so how do I interpret the 2 numbers? for example the numbers Im looking at are 69 above 1.195
Use the built in Tile Map Server to import overlays from Google Maps or Open Street Map. (There are instructions in the Transdem Help pages). These may not be 100% accurate but should give a good idea of where stuff goes. Once you get more experienced then you can maybe experiment with contour maps.
To be honest it is not worth using the built in feature of Transdem to lay out track splines as at best this gives a rough guide. Also remember depending on the region you're modelling and the quality of the DEM data this may not be 100% accurate. Even 20m UK DEM data does not represent every hill accurately. Transdem does give an excellent start to building your route and an overall representation of the terrain, but it doesn't remove lots of the paintaking tasks which must be undertaken before presenting a finished project, or the need to adapt things to how they actually appear in the editor.
To be honest it is not worth using the built in feature of Transdem to lay out track splines as at best this gives a rough guide. Also remember depending on the region you're modelling and the quality of the DEM data this may not be 100% accurate. Even 20m UK DEM data does not represent every hill accurately. Transdem does give an excellent start to building your route and an overall representation of the terrain, but it doesn't remove lots of the paintaking tasks which must be undertaken before presenting a finished project, or the need to adapt things to how they actually appear in the editor.
steamboateng
New member
Different loacilties have their own standards for marking contour maps. The height should be in the same units the linear scale in the map margin is drawn to.
As for the two numbers......, it sounds like 69 is an elevation (feet or meters) and the 1.195 may be a grade indicator (1.195 %) but that's a guess.
TransDEM is not a perfect tool in all instances. It is, as pointed out above, subject to the errors inherent in the downloaded DEM data itself, i.e resolution errors. Additionally, when TrainzDEM generates a map model, it introduces a 'smoothing factor' which can be modified prior to generating a map. The default setting is 2 or 3, I forget which. But this has the effect of smoothing out sharp contours. This is most noticible when defining cuts and fills along the route. It is also noticible along shorelines, where the difinition between shore and water is blended and ill defined.
Sorting out these errors requires a contour map and/or Google Earth. I use both.
As for the two numbers......, it sounds like 69 is an elevation (feet or meters) and the 1.195 may be a grade indicator (1.195 %) but that's a guess.
TransDEM is not a perfect tool in all instances. It is, as pointed out above, subject to the errors inherent in the downloaded DEM data itself, i.e resolution errors. Additionally, when TrainzDEM generates a map model, it introduces a 'smoothing factor' which can be modified prior to generating a map. The default setting is 2 or 3, I forget which. But this has the effect of smoothing out sharp contours. This is most noticible when defining cuts and fills along the route. It is also noticible along shorelines, where the difinition between shore and water is blended and ill defined.
Sorting out these errors requires a contour map and/or Google Earth. I use both.
netting2010
New member
not sure if this is relative but is the height setting in surveyor real units i.e. meters, to reflect the correct elevation of a location?
As to finding elevations I found this site to be good for researching the correct elevation. http://bonzle.com/c/a?a=p&p=19778&cmd=sp&lstt=1
Bound to be an abundance of others.
(this is for those of us who are not up to speed on the technical, computer, side of things.)
As to finding elevations I found this site to be good for researching the correct elevation. http://bonzle.com/c/a?a=p&p=19778&cmd=sp&lstt=1
Bound to be an abundance of others.
(this is for those of us who are not up to speed on the technical, computer, side of things.)
Thanks guys for the responses. At the moment Ive gone back to creating fictional stuff as I do not have enough information on plotting the correct track heights. Some areas/countries seem to have an abundance of information for this sort of thing but the UK does not. Although I can get the hills in the right place and near enough the right height, when it comes to track no. The track in the area I live in goes through several cuttings and over embankments all in a short distance. Ive made several attempts to get it right but the track never seems to match what I can see. So until a more accurate method can be found to get the track heights correct I shall wait.
I'm looking at an old map of a section of track.
What is the source of the old map? Or better, could you scan it and post the image?
Next to it it has 2 numbers - one above the other with an arrow pointing to the center point between the 2 tracks. I presume that this is the elevation for that point? If so how do I interpret the 2 numbers? for example the numbers Im looking at are 69 above 1.195
It would be useful to know the source and exact age of the "old map", and even more useful if you would scan some of it (or take a clear picture with a digital camera), and post the image. Without significantly more information, any thing I would venture as to the interpretation of the two numbers would be just a guess.
I do find that Google Earth gives pretty good elevation data, and you can zoom in quite close to get reasonably accurate elevations at railroad / road grade crossings, and other significant landmarks.
ns
What is the source of the old map? Or better, could you scan it and post the image?
It would be useful to know the source and exact age of the "old map", and even more useful if you would scan some of it (or take a clear picture with a digital camera), and post the image. Without significantly more information, any thing I would venture as to the interpretation of the two numbers would be just a guess.
I do find that Google Earth gives pretty good elevation data, and you can zoom in quite close to get reasonably accurate elevations at railroad / road grade crossings, and other significant landmarks.
ns
The source of the old map is the site www.old-maps.co.uk The map in particular Im looking at is for Droitwich dated 1903 Pre WWII 1:2500. If the map is centered around the junction of the railway you can see some of these numbers just below the junction.
As for Google maps - I must be using it wrong. Every time I try to get a track height from it, I get pretty much the same height as the surrounding landscape even though I know Im clicking above or below an embankment/cutting.
Sorry I cant post an image but I would be breaking copyright laws if I do.
Ah, yes, I see exactly where you are referring to. I also found that if I click on the link "frequently asked questions" at the bottom of the map page, and further select the item, "What do the symbols on the maps mean", and download the pdf linked to by "1:2,500 County Series Map Legend", I can find exactly what these figures mean. And as it turns out, the number "69" is transposed version of the real number on the map, "96", which is a pracel number. The figure below, 1.195, is the size of the parcel in acres. There are a number of elevation points on the map, according to the key. Immediately above the two figures (96 and 1.195) is an abbreviation "L. B." (for letter box), and immediately above that is the word "Station". But if you look closely, between the abbreviation and the word "station" is a small "+", which might seem to be part of the left leg of the "n" in station. To the right of that, off the road, is an italicized number, "132" where the "2" seems is just below and to the left of the initial letter in "Infirmary". According to the key, the cross below the "n" is 132 feet above sea level at Liverpool. A second form of elevation is located immediately above the word "infirmary". The item "B.M. 133.2" indicates that the elevation at a mark on the wall at the point indicated by the arrow to the immediate left, is 133.2 feet above sea level. The cross immediately above, at the end of Union Lane is shown to have an elevation of 129 feet. Bench marks are of less utility than the elevations marked by "+" signs, because the wall, or other item on which the bench mark was made may no longer exist, and even if it does, I suspect that one would not be able to see it in Google, even in street view. There is a reference in the map key to contour line elevations, but I don't see any contour lines on this map (though there may be some there, and I didn't notice them.).
Just for grins and giggles, I fired up Google Earth, and checked the elevations at the end of Union Lane, and the one on Station Street some yards to the South, and found that in both cases, the elevation given in Google Earth (set to display feet) was spot on: the end of Union Street was 129 feet, the one a block south was 132. And yes, you have found a limitation in Google Earth. When I click on the tracks on either side of the viaduct west of Station Street, I get an elevation which suggests either the land, (or perhaps the treetops) along the rail line. However, at the junction of the near the canal, I get an elevation reading of 112 feet, which looking at the elevations in the vicinity on the 1903 map, seems about right.
ns
Just for grins and giggles, I fired up Google Earth, and checked the elevations at the end of Union Lane, and the one on Station Street some yards to the South, and found that in both cases, the elevation given in Google Earth (set to display feet) was spot on: the end of Union Street was 129 feet, the one a block south was 132. And yes, you have found a limitation in Google Earth. When I click on the tracks on either side of the viaduct west of Station Street, I get an elevation which suggests either the land, (or perhaps the treetops) along the rail line. However, at the junction of the near the canal, I get an elevation reading of 112 feet, which looking at the elevations in the vicinity on the 1903 map, seems about right.
ns
Last edited:
Ah, yes, I see exactly where you are referring to. I also found that if I click on the link "frequently asked questions" at the bottom of the map page, and further select the item, "What do the symbols on the maps mean", and download the pdf linked to by "1:2,500 County Series Map Legend", I can find exactly what these figures mean. And as it turns out, the number "69" is transposed version of the real number on the map, "96", which is a pracel number. The figure below, 1.195, is the size of the parcel in acres. There are a number of elevation points on the map, according to the key. Immediately above the two figures (96 and 1.195) is an abbreviation "L. B." (for letter box), and immediately above that is the word "Station". But if you look closely, between the abbreviation and the word "station" is a small "+", which might seem to be part of the left leg of the "n" in station. To the right of that, off the road, is an italicized number, "132" where the "2" seems is just below and to the left of the initial letter in "Infirmary". According to the key, the cross below the "n" is 132 feet above sea level at Liverpool. A second form of elevation is located immediately above the word "infirmary". The item "B.M. 133.2" indicates that the elevation at a mark on the wall at the point indicated by the arrow to the immediate left, is 133.2 feet above sea level. The cross immediately above, at the end of Union Lane is shown to have an elevation of 129 feet. Bench marks are of less utility than the elevations marked by "+" signs, because the wall, or other item on which the bench mark was made may no longer exist, and even if it does, I suspect that one would not be able to see it in Google, even in street view. There is a reference in the map key to contour line elevations, but I don't see any contour lines on this map (though there may be some there, and I didn't notice them.).
Just for grins and giggles, I fired up Google Earth, and checked the elevations at the end of Union Lane, and the one on Station Street some yards to the South, and found that in both cases, the elevation given in Google Earth (set to display feet) was spot on: the end of Union Street was 129 feet, the one a block south was 132. And yes, you have found a limitation in Google Earth. When I click on the tracks on either side of the viaduct west of Station Street, I get an elevation which suggests either the land, (or perhaps the treetops) along the rail line. However, at the junction of the near the canal, I get an elevation reading of 112 feet, which looking at the elevations in the vicinity on the 1903 map, seems about right.
ns
A VERY BIG thank you for your help and explanation. I shall go back and recheck the map for the markers you have pointed out. My issue with google earth was the fact that it gave me a height difference of 2m from one end of the platform to the other. Which is ridiculously steep for a station which is as level or near level as it can be. But again thank you.
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