Tutorial for Creating a SRTM satellite data Scenery.

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Tutorial for Creating a SRTM satellite data Scenery.

Postby Barry » Wed 08 Mar 2006 - 21:54

Tutorial for Creating a SRTM data, route/Scenery for Stentec Simulators.
Download srtm data Eurasia version 2.

http://www2.jpl.nasa.gov/srtm/index.html

Using 3DEM

http://www.visualizationsoftware.com/3dem/

Virtual Terrain in the Scenery Designer Folder or Download

http://www.vterrain.org/

Time taken to make the scenery is a couple of hours as I had to type the tutorial up at the same time as I made it.

Could take weeks tracing contours as in my previous routes.
So from now all my routes will be made using satellite srtm data.

----------------------------------------
1. I am making a route of the Isle of Man as I type this.
I do not know the exact method of setting up the scale in Virtual Terrain.
It appears to adjust the spacing itself in Scenery Designer.
If you set it up in Scenery Designer you get a scenery made of blocks and pillars but the alternative method I describe seems to work OK, with nicely smoothed mountains and terrain.
As always no liabilty accepted and try the method at your own risk.
I do not know the exact method to go about setting up the size but unable to make a usable route if setting the size in the Scenery Designer so set it in Virtual Terrain.

Open 3DEM, File. Load Terrain Model and open the your chosen srtm satellite data, which is an HGT file.
Click SRTM date (HGT).
Click OK and go to to the folder you saved you strm files in.

Operation/Patch missing data, if you wish to remove voids (blue water) caused by cloud cover etc.
Draw a box around the area and press Enter.
If you want a smaller area Operation/Select Smaller Area and press Enter.
File/Save/ USGS ASCII DEM/ - give it a file name and save into a folder.directory of your choice.

---------------------------------------
2. Open Virtual Terrain.
You may have to close it down with Task managaer. Control/Alt/Del
Layer/Import Data/Elevation
Go to the folder where you saved the 3DEM file, open and you get a brightly coloured map.
Export area in top row then Set To Extants.
Just means you have selected all the map I think.
Then elevation in the top row/ Merge and export elevation - give it a file name,and save to your chosen folder.
At the same time there is a Merge and Resample Box.
I click "any size" and make it 2000 for X and Y as a using a square dem map, to get a finer resolution and smooth mountains.
I assume this is height points and the maximum is 2040 or therabouts, (I think) in the Scenery Designer.
Click OK and a message appears to say successfully installed or similar.
This is now the .bt file which we need, in order for the Scenery Sesigner Dem program to process it.
Close Virtual Terrain.
I close it with Program manager - Control/Alt/Del
-------------------------------------

3. Open Scenery Designer.
If using Windows XP you may need to make it compatible to windows 95 to get it to save.
This is at the time of writing 8 march 2006.
Open Dem Builder. File/Open and open your .bt file you made with the Virual Terrain program.
Leave all the details as they are, click OK and it creates the terrain in greyscale,
Click the water symbol at the top and it shows the water and the shape of your land as photographed from the satellite.
All the water however is at zero height.
Which is what it was set at when we looked at in the 3DEM program/
You can increase this in 3DEM but it tend to flood the land if you increase it too much.
You can't decrease it as set to zero.
So dem top row/SET NO DATA/SINGLE HEIGHT/
ZERO is already set, but if not, set it to 0, as we want to get a blank pink dem. for this area to enable to set some water depths.
Click set as new if you want a new file making, rather than overwriting the current file.
Click OK and like magic your zero water height becomes pink dem to work on and I have quite nice detail of te Isle of Man route I a making while I type.
I will put on some approximate depths, so choose the line symbol at the side, type a depth in box at side in metres say minus -10 and draw a thread right next to the land if you want deeper water there. If say a beach you could make it -2 metres.
You need to draw these lines very close to the land.
The depths will slope up or down towards each other.
If too far away from say a cliff, you will get extra unwanted land added as it slopes down towards the sea, etc.
You can use the magnifying glass as the side.
Make sure you click APPLY, after you lay each seperate height, as I think the apply is for the last thread height you set.
Right click to release a thread.
Try and set as many threads as possible to reduce the time it takes to generate the terrain.
Just got an error notice, but used undo, which removed a few threads I set and pressed apply again.
Save this file if you wish - or click Dem at top.Interpolate/OK.
You will see a slider at the bottom of the window moving as it generated the no data area.
It is taking several minutes to interpolate as I should have put more threads on as quicker then, but only for this tutorial so no matter.
Looks like a nice Scenery of the Isle of Man.
When generated click the water symbol at top to see if water OK.

3. Next the simulator need a SCENE file so dem at top convert projection/click scene/OK. Click convert as new if you want a new file of it.
Next you need to remove the no data pink margin, so also crop this margin out.
Side square symbol then edit and crop, name and save to folder of your choice.
Close DeM Builder and open Scenery Builder.
File/New. Box opens and scroll to the file you just saved.
It should open OK if you cropped the pink margins clear as previously detailed.
If it come up with no data you will need to crop the edges again as before as you probably missed a bit of the pink margin.

Scenery opens. Click OK and the scenery generates.
Put a texture on, and quickest to import colours from another suitable scenery already made.
Use my sceneries if you wish and you double click the scenery file to load the colours. Or set you own bands of colours.
Then save scenery to a folder of choice.
Then register, top row button, and save again.
You also then put the starting position on for the boat etc.
Details for making an ordinanry scenery are on my site, so please refer to that for further details.

Tested the route and on digital map measures about 26 miles but in the simulator the scale on map shows about 22 miles. so although it must adjust the spacing to the heights of 2000 I set in Virtual Terrain it is still a little out.
No idea how accurate the scale is in the simulation. press key 2 but at least the process works OK.
Perhaps more information will become available to fine-tune the measurments.

End of Tutorial.

Please note I have made several attempts at making a satellite data route, but if you leave the setting at the default in the Scenery Designer the pixels are huge with pyramids as mountains.

If you set the spacing and heights to create the route size, it turns into a route made of blocks and pillars with no smoothing.
I have only just found about setting the heights in Virtual Terrain and appears to have set the spacing automatically for the scenery to get generated.
Although it appears a bit smaller, according to the simulator scale than it should be, the finished scenery looks excellent, with smooth mountains. So we now only need details of what to alter to get it exact, and so far it does nor work altering the Scenery Designer spacing in metres and number of height points.
Multiply together and they make the size of map.


Thanks

Barrry

P.S. Apparently once the DEM is opened in the Scenery Designer you can adjust the spacing and retain a smoothed route.
The problem is what to set it to now.
Scenery was cropped after converting to scene and further clipped by the grid when generated.
Part is sea and not all land.

Perhaps measure size of dem map in 3DEM.
"Show scale button", then move square by corner or by V in bottom line.
When dem made in Scenery Designer perhaps click, alter spacing and reset spacing to equal 3DEM size less a bit for clipping to scene file conversion.

Best I can think of and added a bit to my tutorial on my site.
Maybe there is another way?

I may put more sceneries on my site and have deleted the 100 mile route.

My future routes will just use srtm data.
Last edited by Barry on Fri 12 Jan 2007 - 23:04, edited 2 times in total.
Barry
 
Posts: 779
Joined: Fri 10 Oct 2003 - 22:07

Thank you

Postby Amtorp » Thu 09 Mar 2006 - 20:27

Barry you are really a GREAT guy taking the time to share width the rest of us.

Søren
Amtorp
 
Posts: 7
Joined: Fri 24 Feb 2006 - 17:21

Postby Barry » Thu 09 Mar 2006 - 22:47

Søren

Thanks for posting and much appreciated.
If trying the method any time and get stuck, just post on forum detailing each stage and will try and help.

Takes a bit of experimenting but Ok when you get into it.
Made myself Majorca today but will have to try and fill in some blank patches with land. Will make it downloadable if I can get it reasonable.

Thanks

Barry
Last edited by Barry on Thu 09 Mar 2006 - 23:25, edited 1 time in total.
Barry
 
Posts: 779
Joined: Fri 10 Oct 2003 - 22:07


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