Sonny's LiDAR Digital Terrain Models of Europe

[Sonny]

I created new DTMs of Germany and Luxembourg

Download: https://sonny.4lima.de

For Germany I used new LiDAR source data of Hessen and Bayern. And the quality of Baden-Württemberg, Saarland, Niedersachsen, Bremen, Schleswig-Holstein, Mecklenburg-Vorpommern got significantly improved, especially in wooden areas.
For Luxembourg I used finer LiDAR source data.

Have a good time!   

[ken888]

High accuracy DEM files are increasingly becoming available. Some are based on 2m, 5m or 10m grids, compared to 30m for the SRTM DEM data. An overlay file of 2m or 5m interval contours can be made for Oruxmaps, from multiple .asc ASCII DEM files, with a Windows PC. .prj files are also required to provide the projection data. Oruxmaps will show these contours as an overlay on other maps eg OSM or OpenAndroMaps.

Gdal can be used to make a kml file from the .asc and .prj files. A full install of Gdal on Windows is complcated. However only 2 Gdal programs are needed here, and they can be obtained by installing only the core gdal programs from the file:
'gdal-3.6.2-1930-x64-core.msi' (34MB) from 'https://www.gisinternals.com/query.html?content=filelist&file=release-1930-x64-gdal-3-6-2-mapserver-8-0-0.zip'
This allows execution of non-Python gdal programs, including gdalbuildvrt and gdal_contour.

Download the required .asc and .prj DEM files and place them in a folder eg C:\Maps\Temp. Tip: If the files are in different folders, use File Explorer search *.asc and *.prj then copy-paste or cut-paste these files into C:\Maps\Temp. Selecting large areas to download will result in very large files and slow operation.

1. Open a cmd.exe window and type: chdir "C:\Program Files\GDAL". Check the gdal installation is ok by typing 'gdalinfo --version'.

2. Make a gdal .vrt file of all the .asc file names: type
gdalbuildvrt "C:\Maps\Temp\All_ASC_Files.vrt" "C:\Maps\Temp\*.asc"

3. Make a KML contour file, eg with 5m interval: type
gdal_contour -a elev -i 5 -f KML "C:\Maps\Temp\All_ASC_Files.vrt" "C:\Maps\Temp\Contours_5m.kml"

4. Copy this kml file into the overlays folder in the oruxmaps folder on the Android (12) phone at.
Internal storage\Android\data\com.orux.oruxmapsDonate\files\oruxmaps\overlay

View the kml file in Google Earth. (File - Open). It is a text file and can viewed and edited in Notepad. Eg the line colour and width can be changed.
Open Oruxmaps. Tap Map icon at top right. Select a suitable map, eg Open Street Map or OpenAndroMap etc. Then Tap Map icon again. Overlay options - Load kml file. Tap kml file. It opens as a transparent overlay of the 5m contours.
This also worked with DEM .tif files. But the files "C:\Program Files\GDAL\projlib\proj.db" and 2 other proj files had to be copied into the GDAL folder.

Making contours and lots more can be done with Qgis. But Qgis has a steep learning curve, and is a 1+ GB download, and 2.4+ GB disk space.

[ken888]

If .prj projection files are not available, the projection data can be added to the gdalbuildvrt file using the -a_srs option. The projection data may be included in a metadata file or in the DEM file name itself.
For example, the ASC DEM file 'PNOA_MDT05_ETRS89_HU30_0179_LID.asc' is a DEM file based on a 5 metre grid from north east Spain, from the website 'http://centrodedescargas.cnig.es/CentroDescargas/catalogo.do?Serie=LIDA2'
The projection data is ETRS89 Zone30N and is included in the filename. The gdalbuildvrt -a_srs option requires a EPSG number. A google search shows that EPSG:25830 and EPSG:3042 may be the correct values.
So the gdalbuildvrt statement is:
gdalbuildvrt -a_srs EPSG:25830 "C:\Maps\Temp\All_ASC_Files.vrt" "C:\Maps\Temp\*.asc"

The file 'PNOA_MDT05_ETRS89_HU30_0179_LID.asc' represents an area approx 28kms by 19kms and is a 190MB file. The KML file produced for this area is about 625MB. This is a very large file and may cause slow operation.
A smaller area of interest can be selected from the large .asc file by using the -te Xmin Ymin Xmax Ymax option for gdalbuildvrt. Use
gdalinfo "C:\Maps\Temp\PNOA_MDT05_ETRS89_HU30_0179_LID.asc"
to see the corner coordinates of the .asc file. Then use the -te option to select an area within it. For example
gdalbuildvrt -a_srs EPSG:25830 -te 757750 4710040 762750 4715040 "C:\Maps\Temp\All_ASC_Files.vrt" "C:\Maps\Temp\*.asc"
selects an area 5km by 5kms at the lower left corner of the DEM file. This produces a KML file size of about 20MB. The file size can be further reduced by converting it to a KMZ compressed file using the 7-Zip program.

[Sonny]

During the last months I worked a lot to create new DTMs, now they are available:

Norway_Mainland v2, Norway_Svalbard v1, Norway_Jan Mayen v1, Denmark_Faroes v1, United Kingdom v2, Ireland v1, Portugal_Mainland v0, Portugal_Madeira v1, Portugal_Azores v1, EUROPE v18

Have fun!

[YvanCB]

Hello,
Thank you Sonny for your great and good job.
Regards.

[Sonny]

Just an update:
Quite a few new DTMs have been released during the last months, especially in Middle- and Eastern Europe.
Have fun with them!

[japetus]

Thanks Sonny, great to see the balkans area to finally start to be included...

[Sonny]

Some News:
Fixed Models: Italy v2b, Austria 0.5" v2
New Models: Cyprus v1, Switzerland 0.5" v2