UK Lidar DSM and DTM

DTM/DSM at 2 m, 1 m, and 0.5 m resolutions:

• https://environment.data.gov.uk/DefraDataDownload/?Mode=survey Outline the region you want. 
• You can get 4x4 of the tiles, or maybe more
•  
  • Navigate to the tile you want, and click.  The data comes in 10x10 km tiles which you pick on the map, and the lidar DSM are in multiple zipped files for each tile.  Each zip will have a number of smaller 1 km tiles.
  • Change the viewing window to have a clear view of the sub tiles available
  • Open the series you want.  Insure you get DSM or DTM, at the scale you want
  • Download away
  • Extract to directories, with a parent directory with "uk-os" in its name.  You can use threads to Decompress.  This will produce a larger number of .ASC files.
  • Use the File, Open submenu,   At least 600 of the 1 km tiles for the 1 m DEM can be merged (610 km tiles for a 2.4 GB DEM) on a system with enough RAM.
    • Open and merge if all the DEMs are in the same directory.
    • Open and merge from directories, and pick the directories you want. Cancel when you have all the directories you want.
  • Reinterpolate DEM to UTM
    •  File, Save DEM, Reinterpolate DEM, UK OS to UTM DEM
• Wales: http://lle.gov.wales/Catalogue/Item/LidarCompositeDataset/?lang=en has a different but generally similar interface.

	Central London.   There are gaps in the data, and it is the luck of the draw whether they occur where you want data.  This 1.5 GB DEM is 20Kx20K postings, and at this scale you really do not appreciate its detail.  The major OSM roads are overlaid. This data was downloaded in Feb 2016; the holes will undoubtedly eventually be filled in.
	Full 1 m detail of the Prime Meridian through Greenwhich.

DTM/DSM for the same area in Portsmouth, UK. The DTM is very generalized, and does not provide a good visualization of what is there.

These do not have any metadata in the data files (which are an inefficient ASCII format).  For MICRODEM you must insure that the path to the files contains the phrase "uk-os".  Other software will require that you identify the projection and datum.

To use in MICRODEM:

• MICRODEM can display the DEMs, but to combine with other data like OSM, you must reproject them to UTM.  Use the option on the File, Save DEM,  Reinterpolate, UTM or lat/long menu.
• Example displays.

Last revised10/26/2017