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  • #26005
    ChristianK
    ChristianK
    Keymaster

    So, here is a map of Scotland for testing with NASA V3 1″ contourlines.
    (Lake district is not covered – sorry)

    https://drive.google.com/open?id=1CNXlKoi_fZD9WxclQENjekZhzhnzSjZr

    Well, the dataset seems to be fine.
    I had a brief look round the Storr and peaks at Glen Brittle on the Isle of Skye – an area I know quite well.

    @John @Geoffmoz
    Please took a look at this map and compare areas you know from your walks with aerial images if the dataset is OK.
    ‚Cause it would’nt make sense to waste 100MB for a dataset thats „looks“ fine but is’nt much more precise than the smaler one.

    If the NASA Dataset is’nt good I would need someone to download the OS Elevation Dataset and to convert it to HGT.

    As for the OS OpenMaps: IMHO This is pure OS Landranger Raster – clear to be seen when I look at the area round the Storr. The cliffs/crags are Landranger, the forrest at the base is not part of OSM but 100% Landranger (I have my old landranger map at hand and I know that the forrest exists cause I walked throug several times)
    And I’m pretty shure that – if I wouuld manage to install my very first version of MemoryMaps on Win7 – that it is for 90% the same as OS OpenData.

    Best regards
    Christian

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    #26007

    geoffmozz
    Teilnehmer

    Christian….that was quick. Well done. I can’t look at it immediately but I’ll get round to studying the map of Scotland over the next few days and report back. Thanks a lot.

    RE: Converting OS OpenData: I’ve downloaded the OS Terrain 50 data and examined some of it in QGIS but I don’t know how to convert it to HGT I’m afraid :-( I’ll do some Googling.

    RE: WayMaps. Here’s a conversation I had with their creators. It explains that they use OS OpenData for contours/crags and which files supply the crag information. They definitely use some OSM data. Here’s Ben Nevis on OpenTopoMap, note the paths between the CIC hut and Carn Mor Dearg. Now find Ben Nevis on the WayMaps, a radio button top right switches between OS and WayMaps. The WayMaps show the two OSM paths from the CIC hut up to Carn Mor Dearg and the OSM path around the CMD arete. These are absent from the OS map. See also the Help from the menu icon top left which explains that they use a mash up of OSM and OS data.

    NOTE: Free registration is needed at WalkLakes for access to the 1:25k OS maps. However you can see the 1:25k OS map of Ben Nevis at Bing maps without registering.

    • Diese Antwort wurde geändert vor 1 Woche, 2 Tagen von  geoffmozz.
    • Diese Antwort wurde geändert vor 1 Woche, 2 Tagen von  geoffmozz.
    • Diese Antwort wurde geändert vor 1 Woche, 2 Tagen von  geoffmozz.
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    #26012
    JohnPercy
    JohnPercy
    Teilnehmer

    I like the increased detail on the Scotland map which looks very helpful to me. However I’m not familiar enough with the area to tell if it’s giving spurious detail..

    As for the OS OpenMaps: IMHO This is pure OS Landranger Raster – clear to be seen when I look at the area round the Storr. The cliffs/crags are Landranger, the forest at the base is not part of OSM but 100% Landranger (I have my old landranger map at hand and I know that the forrest exists cause I walked through several times)

    I’m not quite sure what you are saying here.
    a) Certainly the cliffs and crags come from OS Opendata. I think the folks at the Hug say so somewhere.
    b) The forest at the foot of the Storr appears to come from OS data but woods and forests elsewhere seem to be sourced from OSM data. In my local area of Northampton, Waymaps show woods from OSM data that do not appear on OS maps. As far as I can see Waymaps blend OS and OSM data. I think they are an excellent representation, btw.
    As already said, a lot of OS data is available for free download in both raster and vector formats from https://www.ordnancesurvey.co.uk/opendatadownload/products.html — this includes 10m vertical interval heights based on 50m sampling as grid or contours (vector). I believe however Opendata does not include footpaths as OS doesn’t hold the copyright to them,

    2 Benutzer dankten dem Autor für diesen Beitrag.
    #26014

    Sonny
    Teilnehmer

    @ChristianK

    Sorry, there are no tiles of the shetlands as hgt’s. SRTM is just providing tiles up to 60°North. And ALOS has big voids over the islands, maybe 50% of the area. So you have to use Viewfinder here or OS50 (which are maybe the same in this region)

    The Open data „OS Terrain 50“ consists of 2 files:

    a) Grid: the DTM, which has a grid-size of 50 meters and is about SRTM quality.

    b) Contours: Vector lines of 10 m vertical interval contours. These contour lines are those used on the Screenshots of the walklakes-map. Since they are created based on a original DTM with better resolution than this of a), they are more precise (e.g. narrow corners) than those created using the Grid- DTM of a).
    BUT: these are just vector-data, so no use for OpenAndroMaps besides you have a script to overlay vector data. But I’m afraid it’s not worth the slight improve compared to the contour-lines received by using a) or SRTM.

    2 Benutzer dankten dem Autor für diesen Beitrag.
    #26016
    ChristianK
    ChristianK
    Keymaster

    OK, So if I decide to use 1″ in UK I will use SRTMV3.

    However, Make_Scripts have to be (essential) modified cause these are made to use VIEW_HGTs and – as @sonny have matched LIDAR Data into VIEW1/3 an not SRTM – NASA SRTM should be used in UK only.

    So this will take some time.
    And the GreatBritain Map will be rendered using VIEW3 cause of map-size.

    Maybe I will add a UK_LakeDistrict map.
    UK_Wales is alredy added with the current update but in VIEW3 only (so far)

    Best regards
    Christian

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    #26018

    geoffmozz
    Teilnehmer

    Christian, thanks very much for the work you’ve done creating this map of Scotland. I would like all my OpenAndroMaps to be like it :-) Personally I’d be very happy to have a much larger Great_Britain.map file if it contained these contours for the whole country.

    I really like the extra detail. The steeper, craggier parts of the mountains are more obvious. The bunched contours highlight steeper sections and also the really cliff-like bits are more likely to have rapid changes of directions in the contours over short distances. Contours alone don’t tell the whole story but are perhaps more useful with OSM-based maps because OSM crag markings aren’t great. Of course…you know all this.

    When I walk/climb in the mountains things are pretty easy when following paths but if you head into terrain where there are no paths then the contours and crag information are really useful. The more detailed contours in the V3 Scotland map are good.

    I’ve tried UK_Scotland_V3.map on my old Samsung S4 smartphone. The map still appears quickly and works well. It might be fractionally slower than the Great_Britain.map with 20m interval contours but nothing significant.

    I’ve climbed quite a few mountains in Scotland and have been comparing the Great_Britain.map with the UK_Scotland_V3.map. I’ve linked to a few examples on OpenTopoMap just to show where they are. These are steep rocky parts of the mountains and the more detailed contours in UK_Scotland_V3.map help show this. Good.

    Ben Nevis north face https://opentopomap.org/#map=15/56.80040/-5.00841
    An Teallach east face https://opentopomap.org/#map=15/57.79953/-5.26110
    Aonach Eagach ridge south face https://opentopomap.org/#map=14/56.67521/-5.02363
    Stob Coire Nan Lochan ne face https://opentopomap.org/#map=16/56.64907/-5.02130
    Liatach south face https://opentopomap.org/#map=14/57.55666/-5.48282

    Thanks for your efforts!

    • Diese Antwort wurde geändert vor 1 Woche, 2 Tagen von  geoffmozz.
    • Diese Antwort wurde geändert vor 1 Woche, 2 Tagen von  geoffmozz.
    • Diese Antwort wurde geändert vor 1 Woche, 2 Tagen von  geoffmozz.
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    #26023
    JohnPercy
    JohnPercy
    Teilnehmer

    OK, So if I decide to use 1″ in UK I will use SRTMV3

    What will you do about the Shetlands?

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    #26044
    ChristianK
    ChristianK
    Keymaster

    What will you do about the Shetlands?

    As there is no reliabe 1″ Data I will use the usual fallback to 3″ Viewfinder with 10m spacing.

    However, all this will last a while cause I have to modify the sripts and parameter_sets for _all_ maps cause actually the only parameter for defining the elevation data is
    „1“ – for view1 ans fallback to view3/srtm3
    „3“ – for view3 and fallback to srtm3

    Same for Major/Minor spacings 500/100 versa ???/50
    This have to be changed for all maps to be more flexible in future.

    2 Benutzer dankten dem Autor für diesen Beitrag.
    #26126
    ChristianK
    ChristianK
    Keymaster

    OK, done :-)

    Maps for
    Ireland, UK_Scotland, UK_Wales and UK_LakeDistrict
    with 10m SRTM1/V3 contourlines and Major/Medium intervall of 500/50m (ELE_Labels every 100m) are available for regular download.

    The quality of the dataset is in general – well – quite OK, except for the coastlines/cliffs
    I really hope that there will be free LIDAR data available in the future.

    Best reggards
    Christian

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