Creating terrain heightmaps

  • I would like to give some hints how to get 1m elevation data for Norway.

    The data source is hoydedata no.


    The exact procedure is shown here:

    Google for "transdem Norwegian 1m DEM"


    Clich the world globe in the upper right and select "English"

    These are the correct settings:




    Please be aware, that even small areas generate a huge amount of data!

    The program Transdem is not needed. The conversion will be done with QGIS.


    This article is based on

    qwerty42 's   Creating terrain heightmaps.

    Download sample tfw files from there.



    I dragged and dropped the downloaded TIFF files into the open QGIS ,

    and merged them with "raster / other/ melt:



    and saved them as EPGS:4326, WGS 84. This converts them to a AFS2 compatible format.



    Generate the TFW file too.

    11781-hc-2434-tfw-jpg

    Please take special notice of the negative sign of the vertical layer resolution. ALWAYS (-).


    After this, geoconvert them to level 12 13 14 also 6,7,9 and 10 if the position is north of 60°N.

    6..9 will need to allow masking, as this is a bigger area then your tiff files might cover.



    With these data you will even be able to see smaller sand hills...




    Even the tunnel entrance is carved out whitout dropping the apron:




    Regards,

    Thomas

  • We have to insure that the changes in heightmaps don't cause airports, scenery objects, and cultivation to float above or get eaten by the changes to the maps not read directly by the sim engine. I'm very concerned with this and haven't had a chance to test its effects yet.

    Those that try this please proceed with caution for now.

    I actually noticed this phenomenon. especially in areas where the ground is uneven this is all the more visible. On the other hand, I feel that it only affects buildings and not trees (but I may have misjudged).

    about my tests:
    I carried out the test in a area covered by Level 7 base (imagery and elevation by AFS2), I generated Level 12,13 and 14 elevation for the area.


    ascertainment:

    I noticed that the gap between the building cover and ground is not systematic for the same area ! For example, if I fly only in the area immediately surrounding the first load after launching AFS2, I do not have a "floating buildings" bug. On the other hand if I move away from this area I could see first"floating buildings".

    So from time to time I will be able to have for the same area well placed buildings or floating buildings. It is as if the software loaded at first launch the hight level elevation data (example: Level14) located close around the plane (may be 10,20 ou 30 km²) and put in memory low elevation data (example: Level 7) for the most remote areas. The placement of the buildings being done him at the first loading according to elevation data stored in memory but not being updated during the flight with the update of the terrain elevation data...

    I even tried to split my cultivation files containing the buildings into several files covering smaller areas hoping that the software loads only when the area is flown over but no change unfortunately ( ex: industrial_buildings.toc -> industrial_buildings_54A0_8A60.toc, industrial_buildings_54A0_8A80.toc, industrial_buildings_5460_8A80.toc...)


    [Blocked Image: https://tof.cx/images/2018/04/19/d6abd912fb21f99d4845a55673f3f697.jpg]

  • Hello vogel69 ,

    I think this is partially a caching problem.

    Sometimes this helps: Load an airport 1000 km away.

    Close AFS2. After opening it again, load the original airport with the levitating buildings.


    When in a level 7 DEM area, did you try to also generate 9,10 and 11 in addition to 12-14?

    In general I think, for a 30m MESH, the max resolution should be 12.

    Only for a 1m Mesh it makes sense to go up to 14.


    For comparison: The LOWI ORBX Mesh includes 10+11 only.

  • Hi vogel69 , I could be wrong, but I suspect this issue might be a lot less apparent (or go away altogether) if you used your own data to convert level 7 too instead of using the AeroFly mesh. There might be significant elevation differences between the original data IPACS used to generate level 7 and the data you used for your tiles, which is making this problem visible.

    In addition to that though, it does seem like an issue with how it caches the building elevation without updating them like TomSimMuc explained, which is probably the fundamental problem.

  • Hi all.

    here are a sample for the goedatas at EDDK Airport.

    In the Sim this Data wrong... but i search a few weeks for the Mesh Data.

    At this site there we can see the exact Runways and Taxiways in the terrain.

    Black line rwy, yellow line taxi.

    But i dont no what we can make with JSON Data???

    Is there a tool for json Data to make it with geoconvert?


    Regards ULI


    https://www.geoportal.nrw/


    Shot:


  • AQ, I looked at my elevation notes and remembered that someone posted this comment ...


    "Note that 1/3 arc sec (20m) elevation files only need levels 6-12 generated for FS2" ...


    so you don't need to waste the extra processing time for levels 13 & 14 because it won't improve your elevation detail/resolution.

  • Thanks Chris!

    I see at least the 5m and larger terrain data is under Creative Commons license which should allow for public distribution.

    If only Australians had access to some kind of high speed national broadband network, they may be able to share such data around ;)

    Is this tool a help for terrain highmaps`?


    https://tangrams.github.io/heightmapper/#15/32.6961/-16.7743


    Example here Madeira Funchal Airport...

    click at screen to Base line etc.


    regards


    ULI

  • coxo2436 : I followed the link in crispy136 's post but I couldn't then find any working link to the tutorial. Maybe I'm missing something. Shame the Australian page also isn't working.


    I've come a bit late to this, but I've finally given it a go using qwerty42 's tutorial video - to whom many thanks. It makes an amazing

    difference - particularly to the coastline! Vertical cliffs now drop down to a perfectly level sandy beach, which is what I want to see. At 1/3 arcsec resolution (about 10 m) you'd think there would be be some slight sloping transition, but I couldn't even see that. Banished too are the sharp angled arêtes on mountain slopes. If I see any angles at all (which I rarely do) they're now on very small features like hummocks a few metres high. I tried it out using scenery I made in the far NW corner of Washington state - around Neah Bay. If only we could find a way of using similar data here in the UK. I'm probably going to be spending a lot more time flying in the USA now since it's going to be difficult for me to go back to the default resolution scenery, given that I spend all my time flying low and slow in the helicopter.


    The only thing I did differently from the video tutorial was that I converted levels 7 to 12 rather than levels 12 to 14. Later on I added levels 13 and 14 to see if it made any difference - and it didn't seem to. Having said that, it takes very little time to geoconvert these elevation tiles compared to image tiles (faster than one per second) so there's no great hardship in producing the higher levels. However, as the resolution is about 10 m, level 12 would seem to be all that's needed. There's also the question of storage space. My C-drive (containing my documents folder) is rather small in capacity. Would there be a way of moving them somewhere else as we do with the image files?


    I also wonder how I'm going to manage the transition from one these download areas to the adjacent one. The boundaries of the download areas are certain to cut through Aerofly tiles. In the area I downloaded (maybe 75 x 100 km) all the level 7, 8 and 9 tiles were masked (i.e. cut through by the boundary). Like qwerty, I want to avoid having any mask tiles so maybe the answer is to delete them all and accept that there will be no level 7 and 8 ones - only level 9 (maybe) and above. Also there will be a narrow strip along the boundary with no higher resolution tiles whatsoever. I will have to experiment and see how this looks. This issue doesn't arise with image tiles because, with those, it is possible to choose the download area.


    EDIT: I've uploaded a screenshot to show the improvement gained by using high resolution terrain mesh. This is Cape Flattery at the NW tip of Washington state. Incredibly you can see the rocks actually jutting up out of the sea!



  • Hi Chris


    Is the Australia terrain mesh tutorial still available? I couldn't find the the link.


    Many thanks


    Ian

    Hi Ian, The tutorial is still available for download. You won't see the download link to the tutorial document unless you are logged in to flight-sim.org. Once you have logged in a blue download box appears in the top right of the screen. Regards, Chris

    i used the one in the link above but there seems to be a problem with the ausralian elevation page see pic

    I got the same error so there does seem to be a problem with the data page at present. In Australia, all Government agencies shut down over the Christmas/New Year period. My guess is that either something has broken and there is no-one to fix it, or they have brought that part of the system down for maintenance since everyone is away. You could log a support request with the website owners, but I expect they won't be back until 8 Jan.

    Thanks, Chris

    Win 10 64-bit, 24GB RAM, i5-9400F @ 3.9, 6GB Nvidia RTX-2060

  • Hi Ian, The tutorial is still available for download. You won't see the download link to the tutorial document unless you are logged in to flight-sim.org. Once you have logged in a blue download box appears in the top right of the screen. Regards, Chris

    OK - thanks Chris - I'll try that.


    Further to my previous post on creating high res terrain mesh tiles in the Pacific North West ..... it seems that I was making a bit too much fuss about the fact that a lot of them are masked. I've now created 2 adjacent areas along the Pacific coast with a boundary at 48 degrees north. Flying down the coast I have detected no problems so far whilst crossing the boundary. It seems like the masked TTH files are different from the TTC files anyway - the TTH masked tiles aren't produced in pairs like the TTC ones are. Maybe this is why the command to reject them doesn't work in the TMC file? I'm not sure I fully understand how masked tiles work - I only know that they used to cause me enormous problems during my early attempts to create scenery, so I decided to make sure I never had any in the scenery. With the terrain mesh they don't appear to be a problem - so far!


    EDIT 14 Jan: It seems I spoke too soon. There are in fact issues along the boundaries between adjacent 1x1 degree download areas. I must have just been lucky (or unlucky) when I first looked (above). There are in fact 2 parallel rifts/discontinuities along the boundaries whose height varies according to the discrepancy between the default and the high res terrain mesh. In flat lowland areas this might scarcely be noticeable. These discontinuities look at first like vertical cliffs, until you notice that they form a perfect line in the N-S or E-W direction. The 2 discontinuities are typically a couple of km apart. This is clearly due to the masked TTH tiles at the boundaries. In the band between the discontinuites the terrain mesh is default. (I was actually expecting the strip between the discontinuities to be flat and at sea level, by analogy with the black areas caused by masked TTC files - but luckily this is not the case.)


    I'm not sure what can be done about this. It's not a massive deal given that the download areas are quite large. 1x1 degree corresponds to 100 x 60 km or so - and cliffs and default mesh are not as offensive to the eye as black strips. I wonder if there would be any way of stitching the download areas together before geoconverting them? Maybe editing the TMC file so that it encompassed a rectangle of several download areas? I haven't tried that yet. Even then there would inevitably be a boundary somewhere - just pushed further out.

  • Just an update on my experience with high res terrain mesh in the USA.


    I've managed to get rid of the discontinuities / "cliffs" between adjacent 1 x 1 degree download areas by geoconverting a 2 x 2 block of them together, using a TMC file whose NW co-ordinates are the NW corner of the northwestern-most 1x1 degree area and whose SE co-ordinates are the SE corner of the southeastern-most 1x1 degree area. I put all the TIF files and their corresponding TFW files together in the "input_aerial_images" folder. This eliminates all the masked tiles on the boundaries and pushes the problem to the outer boundary which can, of course, be as large as you like. The block could be 2 x 2, 4 x 4 or whatever.


    I've also attached a couple of comparison screenshots below. They were taken on the Elwha River SW of Port Angeles, Washington State. The top one is with the high res terrain mesh and the bottom one is with the default mesh. Note in particular the ravine, which is completely absent in the default mesh screenshot and very well defined in the high res shot.


  • So, is this super elevation file something that can be shared? The comparison images are very impressive. Good creative work.


    Regards,

    Ray