Viewing 6 posts - 31 through 36 (of 36 total)
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  • #43800
    Enivex
    Participant

    Extremely good height data for Norway is available here https://hoydedata.no/LaserInnsyn/ (language can be changed to English top right), as part of the new National Elevation Model. These are openly available, as you can check under “Licensing and user feedback” under the question-mark at the top.

    “All available datasets available without logging in are open and covered by CC BY 4.0.”

    If you click Download on the left-hand side, then choose the “National datasets” tab and “UTM 33” (the only one that covers the entire country) you will see DTM files available for download.

    The 17 GB DTM10 file, which contains 10 meter data, is probably (?) the one you want. There are also DTM1 files available for download, but they are extremely large (1-2 TB total I believe).

    The project isn’t entirely finished yet (will be by the end of 2022 I believe), but the vast majority of the country has 1 meter data already. The places that aren’t yet covered have slightly lower resolution (2-10 meters I believe depending on the location), but are included in the data so there are no holes.

    It would be fantastic if this data could be incorporated, as it would be a massive upgrade over the existing 20 meter contours in Norway.

    (You may already be aware of this, but I decided to post it here anyway.)

    #43806
    Sonny
    Participant

    Thank you Enivex. I can satisfy you with the fact, that this is exactely the source I used to create the Norwegian DTMs ;-)
    (You can check the used sources within the “Readme.txt” file of each DTM)

    That fact that I’m generally providing DTMs with a minimum of 20m resolution (exeptions are the relative small alpine countries of Austria and Switzerland, where also a 10 m version is available), is undependend of the grid width of the used source data. Sometimes I even used LIDAR source data with 0.5m resolution.

    #43811
    Enivex
    Participant

    Oh, I should’ve checked that beforehand, but assumed that you didn’t since the contours had a distance of 20 and not 10 m. Is the reason for not providing the higher density contour lines that the file size becomes too large for larger countries? Maybe hosting through a torrent could be a possibility.

    There are a lot of elevation changes here in Norway, and 20 meters is often not enough to see a lot of details.

    #43815
    Sonny
    Participant

    By the way: The vertical interval of the contour lines of maps using my elevation data (e.g. OpenAndroMaps) is completely undependend of the horizontal resolution of the elevation data.

    Theoretically you can create maps with contour lines which have a vertical interval of 1 m, based on elevation models with a horizontal resolution of 50 m. It’s of course not clever to do – but it’s possible.

    So if you want to have a vertical contour interval of 10 m for Norway, you have to convince the map provider (Christian) and Elevate-Theme creator (Tobias) of your idea ;-)

    #43819
    Enivex
    Participant

    I realize that they’re independent, but without sufficient horizontal resolution the quality of the resulting contour lines isn’t going to be all that great. As far as I understand, the countries that have 10m contour intervals also have 10 meter horizontal resolution data from you. For instance “DTM Switzerland 10m v2 by Sonny”. On https://data.opendataportal.at/dataset/dtm-norway I only see 20m.

    I could contact the map provider to ask for 10 m contour lines, but wouldn’t that first require higher resolution data to make much sense? Especially with the kind of terrain we have in Norway.

    #43822
    Sonny
    Participant

    I’m intentional offering DTMs with a minimum resolution of 20m or 1″. If somebody needs finer resoluted DTMs, he’s free to download the original elevation data provided by the countries’ institutes. Providing finer DTMs than 20 m (exceptions are Austria, Switzerland) is beyond the purpose of my DTMs.

    Btw, OAM is not using the meter models, but the 1″-versions of my DTMs. I doubt that it’s worth to deal with DTMs of 10m resolution for creating contour lines of hiking/cycling maps. The pratical improvements will hardly be noticable besides for steep, high, irregular rocks.

    The additional(software technical) reasons why this is not a good idea – especially for large countries – will have to be explained by Christian.

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