InforShell

DEM 90m, DEM 30m

Services to fill large DEM holes
90m or 30m horizontal resolution, 1m vertical resolution



About DEM 90m (SRTM3) data

DEM 90m (abbreviation) is a dataset that is a global terrain Digital Elevation Model excluding polar regions. At 90m horizontal resolution, each data point represents the elevation of a 90m x 90m area of land surface. The original dataset is provided by NASA, composed of individual data files (tiles) each covering an area 1 degree longitude x 1 degree lattitude.

Due to various limitations in the remote sensing technique:

  • Some data files have sparse and small data holes, example shown in Fig 1.

  • Certain data files have concentrated and large data holes, example shown in Fig 2.
  • Inspection of files exhibiting data holes show that they occur significantly in areas under long term snow, ice, and water coverage. These holes reduce and limit the readability and usefulness of DEM 90m.




    Figure 1. A region in the DEM 90m dataset with sparse small data holes, shown as blue spots.
    (Shaded relief false color visualization.)



    Figure 2. A region in the DEM 90m dataset exhibiting concentrated large data holes, shown as blue areas.
    (Shaded relief false color visualization.)
    Global Coverage (~90m) Version 2, file name N35E076.hgt



    Services to fill in large area data holes in DEM 90m (SRTM3)

    For developing applications using a DEM, accurate data hole filling, particularly of large areas illustrated above, will significantly enhance its readability and usefullness. InforShell provides this service for customers, using a reiterative, high resolution, nearest-neighbour based algorithm that refers to related data points from a 1km resolution hole-less DEM (also provided by NASA) as basis. The earlier example area after hole filling is shown in Fig 3. After processing, the output DEM 90m files will maintain the original data format as utilized by NASA, in the form of 1 degree x 1 degree tiles.

    If you require this DEM hole filling service, please contact us at sales@InforShell.com.


    Figure 3. Output after hole filling processing, same area as shown in Figure 2.
    (Shaded relief false color visualization.)



    Services to fill in large area data holes in DEM 30m (SRTM1)

    DEM 30m (abbreviation) is a dataset that is a global terrain Digital Elevation Model excluding polar regions. At 30m horizontal resolution, each data point represents the elevation of a 30m x 30m area of land surface. The original dataset is provided by NASA, composed of individual data files (tiles) each covering an area 1 degree longitude x 1 degree lattitude.

    Due to various limitations in the remote sensing technique:

  • Some data files have sparse and small data holes.

  • Certain data files have concentrated and large data holes, example shown in Fig 4.

  • Figure 4. A region in the DEM 30m dataset exhibiting concentrated large data holes, shown as blue areas.
    (Shaded relief false color visualization.)
    (~30m) Version 2, File name N36W113.hgt

    For developing applications using a DEM, accurate data hole filling, particularly of large areas illustrated above, will significantly enhance its readability and usefullness. InforShell provides this service for customers, using a reiterative, high resolution, nearest-neighbour based algorithm that refers to related data points from a 1km resolution hole-less DEM (also provided by NASA) as basis. The earlier example area after hole filling is shown in Fig 5. After processing, the output DEM 30m files will maintain the original data format as utilized by NASA, in the form of 1 degree x 1 degree tiles.

    If you require this DEM hole filling service, please contact us at sales@InforShell.com.


    Figure 5. Output after hole filling processing, same area as shown in Figure 4. (Shaded relief false color visualization.)