March 13th, 2008, 12:50 PM
I was wondering how I would take a 1km square from a Topo map and create it for the terrain representing the same size. I have the tutiorial on how to make my own DEM but i need to know how to represent a 1km square on a basemap...
March 13th, 2008, 03:08 PM
Base boards are 720m on a side. Don't know why. No one seems to know. Anyway, the grid drawn on the baseboard is 10m on a side. So one baseboard plus 28 grid squares is 1KM.
Or you could use microDEM and HOG to move the map. HOG automatically maps the elevation data correctly. If you start with 10 meter data, you'll get an elevation point at each grid intersection.
March 13th, 2008, 05:50 PM
OK so say if I wanted to crop out a 1km square from my topo map and after all the proper conversions wanted that to cover 1km in trainz, what size should the image be in photoshop as far as pixels?
March 13th, 2008, 06:17 PM
robby2, it sounds like what you might be best doing is using "1km Basemap A" by g0akh, kuid 119912 60004, which is on the DLS. It is a 1 km square box on which you place the map graphic of your choice. You just replace the 1024x1024 pixel TGA or BMP that comes with the object with your own 1024x1024 pixel TGA or BMP 1km map. Place the Basemap on some blank trainz baseboards and off you go. The basemap may be raised and lowered so you can put it out of sight as you need to in order to place scenery. Trainz scale is 1024 pixels to the kilometer.
March 14th, 2008, 09:16 AM
I actually did some trial and error last night and when the image i use for the DEM put through HOG is 1024 pixels the map generated for trainz is 10 km or 10000 meters. Is it different when you run through HOG than if yuo just use a image pasted in the BasemapA folder like you were describing?
March 14th, 2008, 12:38 PM
Actually, now that you raise the question, I am a bit confused myself. Wewains tutorial on using HOG & MicroDEM talks about setting the elevation display so that 1 pixel represents 1 meter of real life distance. This would imply that the Baseboard using a 1024 pixel image is a little bit fudged for convenience and that true scale is really 1000 pixels for a kilometer.
Wewain then goes on to talk about adjusting the DEM's scale to a "screen pixel size of ten meters". How this gives you 1 pixel representing 1 meter is just not clear to me. Perhaps some of our more knowledgable HOG gurus could weigh in on this point.
March 14th, 2008, 02:37 PM
HOG is set up so that 1 pixel = 10m in the horizontal directions. This will result in full size terrain and all the image files used with it should be the same scale and size.
There is a bit of complication with HOG that most seem to ignore. The map file format actually requires 76 data points per side on a baseboard not 73 as you'd expect for a grid with 72 spaces. There are 3 extra points 2 on 1 side and 1 on the opposite that should match up with the data on the adjoining baseboards. For adjacent boards the extra points are already in the image data but along the edges of the map you have to provide them. The image file for HOG is normally 72 x no of baseboards wide + 4 pixels by 72 x no of baseboards high + 4 pixels. EDIT: changed 3 additional to 4 additional pixels as the last board needs 73 not 72 pixels so we get 3 + 1 = 4.
If you are using the filter baseboard option however you can usually ignore this as HOG will use what's available in the image as it filters the boards along the track route define in the image. Normally with a rectangular image you have enough extra around the track route that HOG doesn't try to use baseboards that extend beyond the available data.
If you ignore the above size requirement and don't use the filter option you can end up with baseboards along the edge of the route that are partially terrained where HOG runs out of data to complete a full board.
Using a 1024 x 1024 image with HOG has enough data for abt 14.19 x 14.19 baseboards. You should get 15 x 15 with the 15th row and column baseboards only partially terrained.
The 1km basemap is a mesh item and the image file was mapped to it in gmax. Using a 1024 image is supposed to give you full size but I never verified that. However whatever image size you use is always mapped to 1km.
HOG is different it uses the pixel value in the image file as a height value to apply to a baseboard grid point. There is always a 1 to 1 correspondance of pixels in the image file to grid points on the baseboard.
Last edited by RPearson; March 14th, 2008 at 07:13 PM.
Member since 6-14-2002
March 14th, 2008, 03:24 PM
so with that being said, what size image would I need to pass through HOG to get 1KM? I tried with 125 pixels and got around 720 M. I guess i could continue to try and error but if yuo have the answer off the bat it would help.
Also the HOG filter option, could you explain this further and let me know how to invoke it?
March 14th, 2008, 09:51 PM
DEM/HOG and Basemaps are two entirely seperate systems. I'm not at all sure how to use a topo map in HOG, or if you even can.
Here's the info I have...
These are scenery items, 1km on a side. I've used these with topomaps to make routes. It's a little tedious, but the results can be surprisingly good.
Technically, this can best be used to generate U.S. routes, since it depends on USGS Tiger data. Any valid DEM data can be used to generate terrain, however, so if you don't mind drawing in the details on the finished baseboards, it can be used anywhere that elevation data is available.