Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25
Like Tree3Likes

Thread: Ordnance Survey releases map data free

  1. #11
      Redrobes is offline
    Software Dev/Rep Redrobes's Avatar
    Join Date
    Dec 2007
    Location
    England
    Posts
    4,776
    Blog Entries
    4

    Default

    Ah ok, well bin is somewhat arbitrary binary files so we need to know what format binary it can take. I was sure wilbur or something could read arc ascii. I can generate .BT, .HF2, a RAW which is also pretty arbitrary or just do a greyscale which looses a lot of info.

    I have been coding up the script to run it against all the tiles they supply, then render out the height maps, then shade them using the MEDem procedural shader to get a view of the whole UK. Here is a pic or two - click for improved size. There are some irregularities near to sea level and this has no bathymetry data in it so its hard to shade against that. It seems Norfolk is below sea level in this data - I was not sure that was the case but maybe it is. It may also be that the sea level is not a constant at 0 and its using the Newlyn Datum which may mean that the sea is higher to the right of Britain - Not sure at this point...


  2. #12
      ravells is offline
    Community Leader Gracious Donor ravells's Avatar
    Join Date
    Jun 2006
    Location
    London, UK
    Posts
    10,901

    Default

    That looks great! I can import .BIL files from the USGS into FT Pro. I've just downloaded the ASCII format one but that looks like loads of separate folders containing zip files which I don't think that FT Pro can read in my limited experience.

  3. #13
    Professional Artist Facebook Connected Schwarzkreuz's Avatar
    Join Date
    Oct 2011
    Location
    Leipzig/Berlin
    Posts
    1,471

    Default

    Hi, I don't realy understand all of this, but I would love to use some of this data to generate Landscapes for Arden. Is this possible with Wilbur? (I just started to learn it last weekend)

    This all is looking fantastic.

    {The Mapforge}


    Cartography Portfolio


  4. #14
      Redrobes is offline
    Software Dev/Rep Redrobes's Avatar
    Join Date
    Dec 2007
    Location
    England
    Posts
    4,776
    Blog Entries
    4

    Default

    I had one zip containing loads of more zips under data folder. The other zips have the normal OS 2 letter code like SH etc which are the 100km square patches that cover the UK - (see https://en.wikipedia.org/wiki/Ordnan..._National_Grid). So you can use 7zip to extract all the asc files in one go by using "7zip e *.zip *.asc" and it runs through them all extracting all asc files. Then you have something like 25 x 10 x 10 asc files of the uncompressed data in 10Km x 10Km tiles. Doing a quick google it seems QGis can open ArcAscii files ok. Maybe it will export to something FT can read. Each asc file also contails the lat long X & Y so maybe you can open many of them and build up a seamless expanse of DEM data.

    Can you use these DEMs with other maps like Arden - sure, we use various DEM height data for MEDem mountains since its hard to get any app to generate proper realistic mountains. Apps can do a semi good job but up close in Outerra they look terrible. Theres loads of DEM sources you can use. Most people use the SRTM from NASA which is public domain and covers almost the whole globe. Then you can pick out Himalayas etc for good mountains. How you shade and colour your maps based on the DEMs is up to you tho. So search on this site for SRTM and there will be lists of sources to get at them - I think for fantasy maps these are better. But if your specifically after accurate UK dem data then this has up to this point been unavailable to an accuracy much better than the SRTM of the UK.

  5. #15
    Professional Artist Facebook Connected Schwarzkreuz's Avatar
    Join Date
    Oct 2011
    Location
    Leipzig/Berlin
    Posts
    1,471

    Default

    Hi Redrobes, I am completely new to this and barely understand what you are telling me. I dont even know where to start. I saw some Middle earth Renders a while ago, but well, i need a starting point from where I can beginn to understand this more.

    {The Mapforge}


    Cartography Portfolio


  6. #16
      Redrobes is offline
    Software Dev/Rep Redrobes's Avatar
    Join Date
    Dec 2007
    Location
    England
    Posts
    4,776
    Blog Entries
    4

    Default

    Monks is a better person to ask as I run a lot of custom apps and tho the main make run of MeDem for Outerra is generated on my apps Monks models the whole place using off the shelf stuff. I would definitely look at Wilbur tho since a) its free and b) Waldronate knows everything there is to know about it. I only use HF2 format since it was custom designed by a group of us to handle large extended height fields but Wilbur loads in many types of formats and has a user interface whereas mine are all command line script type stuff which is all batched up and put into makefiles - it drives Monks crazy that I don't have a UI. My stuff is so hard to use occasionally I have to get the source code out and run it in debug mode just to see what the hell is going on and why its not outputting the right stuff. So yeah, Wilbur & QGis are good starts. You can find greyscale height maps of lots of stuff and you can download my extremely basic height map viewer from my web site - see sig or here. I used that for the pics in post #9 above.

    In a way were all trying to work out the best way to do 3D terrain modelling since nobody has yet come up with a cast iron fool proof way to generate really realistic terrain that could fool the trained eye. So on MeDem Monks mainly uses Global Mapper but also Wilbur, and loads of other tools too. We restrict ourselves to wanting correct hydrology too which is also a tough call. We both think the right way to make an app is to use drainage basins and catchment areas and sculpt whilst the water is flowing but we need a bit of a jump in compute power - even with the GPU its still a bit off that at the mo.

  7. #17
      Redrobes is offline
    Software Dev/Rep Redrobes's Avatar
    Join Date
    Dec 2007
    Location
    England
    Posts
    4,776
    Blog Entries
    4

    Default

    Just done another with procedural veg calculation. This is about as far as I can take it with this data.

    Last edited by Redrobes; 09-26-2013 at 07:45 PM.
    Chashio likes this.

  8. #18
      waldronate is offline
    Software Dev/Rep Gracious Donor waldronate's Avatar
    Join Date
    Mar 2007
    Location
    The High Desert
    Posts
    1,496

    Default

    You can also push the sets through GDAL to generate a HF2 file that Wilbur should be able to read. Wilbur and FT can both handle arbitrary uncompressed binary rasters (that is, rectangular blocks of byte/int16/int32/ieee-754 float samples in big endian/litte endian order). The 32-bit FT version is pretty much limited to about 1GB or smaller data files, though.

    Looking at the data, it's pretty obvious that there are large sections that were made from digitized contours (unless the landscape truly is composed of facets a few hundred to a few thousand meters across). It looks a lot like the USGS United States data from the 1970s, which may not be surprising as the data set is from roughly the same era as indicated on the web site. I'm wondering if it really offers much beyond the SRTM 90m data set for the same area except for a historical perspective.

    The easiest way to check for faceting in data is to set the light to 90 degrees elevation and set a large vertical exagerration (100 or more) before doing hillshading. The artificial areas and lakes will usually stand out as much brighter than the areas with noise usually associated with electronic altitude gathering. As a bit of amusement, a USGS DEM of an area near my own local area was constructed from two different years of electronic data. One of those years was a wet year and one was a drought year. The largest reservoir in the area was split across the two data sets, making a 20 foot sloep in the middle of the lake from where the automated patching happened.
    Last edited by waldronate; 09-26-2013 at 11:25 PM.
    ravells likes this.

  9. #19
      Redrobes is offline
    Software Dev/Rep Redrobes's Avatar
    Join Date
    Dec 2007
    Location
    England
    Posts
    4,776
    Blog Entries
    4

    Default

    If Wilbur can read HF2 then thats cool, I could convert some data for Ravs.

    I am not seeing any faceting in this data tho. Cant understand where you get the idea this is from a vectored source. I think were looking at different data then. Mine all looks a lot like my pics in #9. The data is at 50m spacing so its nearly twice as good as the 90m USGS and since SRTM was 1km then its 20x as good as that. This is the best whole UK DEM source I know of tho I am sure there are localized much higher res LIDAR data around somewhere.

  10. #20

Page 2 of 3 FirstFirst 123 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •