Convert to Ordnance Survey Projection

General question for Sail Simulator (raising sails, pulling sheets, etc.)

Convert to Ordnance Survey Projection

Postby nigelcrss » Sat 03 Feb 2007 - 12:03

Can anyone tell me how to convert SRTM data into a map that has the same projection as Ordnance Survey Maps in the UK. I have 3DEM software.

Any help appreciated fellas.

Thanks

Nigel
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Re: Convert to Ordnance Survey Projection

Postby Barry » Sat 03 Feb 2007 - 13:58

nigelcrss wrote:Can anyone tell me how to convert SRTM data into a map that has the same projection as Ordnance Survey Maps in the UK. I have 3DEM software.

Any help appreciated fellas.

Thanks

Nigel


Nigel Hi

As far as I know you just change to UTM Projection from UTM Ellipsoid.
At least thats what I did for all my sceneries, otherwise the map is distorted. Once you change to UTM the measurements then seem about the same as the OS map and the finished scenery is about the the same measurement as the OS map.

You can measure the map in 3dem to check it against OS map. Mouse on corner of square with notch and enlarge to cover area required. move into place holding notch or bottom of square with mouse.
Then Colour Scale/Show Scale/Metres or Feet. The value changes as you enlarge square etc.

Please refer to my tutorial if required at link below.
"Click Operation - Change Projection - Convert to UTM Projection and click WGS84 and OK."

Maybe there is another way but don't know of it at present.

Barry
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Postby nigelcrss » Sun 04 Feb 2007 - 09:25

Hi Barry,

Thanks for your reply. The tutorial is easy to follow and produces a result which as you say looks to be about right. Thank you!

I want to use the SRTM data to produce a map of the entire Uk. But if I try to open more than about 9 SRTM data files the program does nothing. I suspect that this is because I only have 128MB of memory in a 6 year old computer. Am I correct in my analyse or does 3DEM limit the number of files you can open. I intend to purchase a new computer with 1 or 2 GB of RAM and Windows XP Professional. If I purchase such a system do you think that I would be able to open about 80 files at once?

Any further information appreciated.

Thanks

Nigel
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Postby Barry » Sun 04 Feb 2007 - 14:37

Hello Nigel

I think it just depends on the amount of memory on the graphics card I think and it mentions somewhere in 3dem I think about it. I can only up about 6 or 7, but usually only use 2 or 3 sections to cover a smaller area and crop it to about 40 to 60 miles.

I have made most of the west coast of the UK in the 14 sceneries available from Stentec's site. I was going to complete the whole coastline but waiting till I get a new computer in a few months to see if the Stentec programs will still work with it. I think I will get 2000 Ram though with Vista as only 500 now. I

To make the whole lot in in 1 go would make a huge pixel size full of huge jagged edges to the coast and to the mountains. I found that a rough guidleline say 20 miles makes a pixel size of about 20 metres. 40 miles 40 metres. 1000 miles would be at 1000 metre pixels size!.
I doubt if the rivers and estuaries would show?

I kept most of my sceneries at about 40 to 60 miles I think and overlapped each section to make them continuous. The detailed Conway river and Estuary I made about 20 miles for about 20 metre pixel size size so that I could open the river up along it's length.

If you keep the pixel size low you can open up the rivers and bays etc by using no data as detailed in tutorial, either by outlining the edges of rivers then clear the middle or draw a square around each section of a river working along it and making no data plus 1, plus 2 plus 3. etc. Rivers follow the lowest land level so you can gradually open them up.

You may have problems with low lying land such as the Thames Estuary as the satellite data is 90 metres basic so small islets and inlets may need putting on manually by making them plus in dem editor. Did try the Thames but all very low lying so just kept to the West Coast.

Nice to have a chat and keep us posted on how you get on.

Barry

:)
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Postby nigelcrss » Mon 05 Feb 2007 - 09:41

Cheers Barry,

More useful information which actually helps to explain a lot of what I had observed.

Yes the manual does seem to say that: "The only limit to the number of DEMs that can be merged is memory in your computer". Which I guess would be a combination of RAM and Graphics card memory.

I have been playing with the free version of Terragen v.90. The landscapes created look pretty ordinary in that and but I am thinking of paying for the full newer version 2 when I get my computer upgrade. I hope that it will produce some good results for the landscape.

I hope your new computer cuts the mustard. Keep up the good work!

Nice chatting

Cheers

Nigel



[url]resourcesforhistory.com[/url]
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Postby Barry » Mon 05 Feb 2007 - 14:14

nigelcrss wrote:Cheers Barry,

More useful information which actually helps to explain a lot of what I had observed.

Yes the manual does seem to say that: "The only limit to the number of DEMs that can be merged is memory in your computer". Which I guess would be a combination of RAM and Graphics card memory.

I have been playing with the free version of Terragen v.90. The landscapes created look pretty ordinary in that and but I am thinking of paying for the full newer version 2 when I get my computer upgrade. I hope that it will produce some good results for the landscape.

I hope your new computer cuts the mustard. Keep up the good work!

Nice chatting

Cheers

Nigel



[url]resourcesforhistory.com[/url]


Hello Nigel

Everything apparently needs to be done through the Stentec dem editor?
When I first tried making sceneries with 3dem I got nowhere as the srtm2 terain from 3D when imported into The Stentec dem editor was about the correct height but made from a series of steps or blocks.

It was only when Jeroen from Stentec posted about using Virtual Terrain to convert to the .bt file then import into dem editor that it worked OK, as had about given up on it all.

Also Stentec is working on a new scenery designer according to their update in conjunction with SS5. forecast for November and Beta testing Sept but dates may alter I suppose.
Wouldn't know how Terragen v90 would fit into it?

If you find out more re Terragen maybe keep us posted.

Thanks

Barry
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Postby nigelcrss » Mon 05 Feb 2007 - 16:15

Thanks again Barry.

I've been working with Terragen again tonight and I have actually made enough progress to colour the landscape more realistically than I have managed before. So I will keep you posted at intervals.

I am actually trying to visually recreate the old Roman lighthouses in situation as they would have been at the entrance to Dover harbour.

I will look more at the programmes which you listed in due course.

Cheers

Nigel
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Postby Barry » Thu 22 Feb 2007 - 13:20

nigelcrss wrote:Thanks again Barry.

I've been working with Terragen again tonight and I have actually made enough progress to colour the landscape more realistically than I have managed before. So I will keep you posted at intervals.

I am actually trying to visually recreate the old Roman lighthouses in situation as they would have been at the entrance to Dover harbour.

I will look more at the programmes which you listed in due course.

Cheers

Nigel


Hi Nigel.
Just had a look at you site and now understand better.
Incidentally your link wasn't live so posted it again.
Just copy the internet link seems to work OK in signature, etc.

http://resourcesforhistory.com/

My main interests are the ages past especially with the Stentec simulators (and everything else probably).
With the Stentec simulators I concentrate just on the pre- industrial age of about 2 centuries back, real age of sail and canals, etc. Also less developed areas as mainly rural then so easier to make.

I used Trainz the train simulator and gmax a few years ago to create sceneries with and without trains, with Liverpool docks, horse drawn canal boats, and drivable square rig sailing ships as in my sceneries in Stentec.
As regards the train program a train shape is an object so used boats instead of trains on invisible track, etc.

Liverpool docks I based on plans of about 1830 as in my Stentec scenery of the river Mersey.

Only mentioned as background,because if you find out more how to create historical sceneries using the Stentec simulators, or other user-friendly programs and preferably open source methods please post.

Crystal Space, Celstart, Ogre are all Open source I think but probably too complex for me at present. Ogre needs C++ knowledge I think at present.

Did consider making the Liverpool area and Mersey Estuary when the first dock was made in the early 18th Century.
However with "Vista", no longer sure what will work when I get new computer in few months, and Stentec's next version of Scenery editor probably STILL many moons away.

Thanks

Barry

:)
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Postby ajnasreddin » Mon 04 Jun 2007 - 20:09

Hello Nigel and Barry,

Nice thread. Last summer I was working on some sceneries, but I stopped because of various issues with the program not working on my computer. However, I always keep an eye on such discussions while waiting for SS5.

I played around with Terragen myself. Nice program with some interesting results. However, my sloooow internet connection will make it difficult to buy and download and use with SS5. I will need to look into it and see if it is aviable on CD.

Do either of you know if we will be able to sail into sceneries, one to another, in SS5? I seem to remember reading something about this but can't find it now. This would be nice because a 20 meter square is still pretty big - even a quarter of that is pretty big, especially if you talk about canals and rivers. Obviously using satelite data would need some tweaking to make things look smooth.

Also, concerning different eras, it would be nice if dates were noted in your sceneries' descriptions. By the way, how are you representing changing coastlines?

Again, thanks for the info. Even if some of us are not doing anything now, the information will be useful later on.

AJ
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Postby Barry » Mon 04 Jun 2007 - 23:32

Hello AJ.
Regarding sailing from one scenery into another I remember like yourself, a long while ago a mention of allowing larger sceneries by moving the position, but have forgotten the technical details.
maybe on old forum.
You can sail from one scenery into another in Virtual sailor and it loads the new scenery each time so should be possible in SS5, but little info at present from Stentec so we guess.

I hope Stentec put all the bits together to make satellite data sceneries, otherwise it won't be any better than what we have.
You have to use 3 seperate software programs at present.
First you have to try and download 3dem and that is dependant on the availability of it.
Next we need VT builder to make the .bt file. At present that is included in the Scenery Designer but to download a copy I think there is a registration procedure. Also the program doesn't close on my computer without using task manager. If you get that far then we are into the dem editor and scenery designer.
This I think is another reason why so few people have made sceneries as not user friendly enough at present and people are put off as soon as they start.

I have added these details as may be useful to Stentec but they must already know them as they designed the program, so not a criticism. as the scenery designer program is 5 years or more old I think, just hopeful the next version will be a little more user friendly, as then anybody can make almost anything they want in sceneries and then usable for years to come by anyone interested, probably by me anyway god willing.

Regarding trying to create older sceneries it is virtually impossible I think to create depths as they were then, as some rivers have now almost silted up, like the Conway. The river Mersey was constantly changing its channels and new ports opened and closed depending on how far upriver the ships could get and the same with the river Dee.

Scenery making with me is on hold at present until SS5.

Barry
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