How do I find the altitude of plant locations?
You do not need to be logged in to the DDb to use the ‘Grid-reference lookup tool’. This is found via the Tools tab on the DDb home page, or at https://database.bsbi.org/gridref.php.
Entering the 100m grid reference NJ123123 and clicking on ‘look-up grid reference’ opens a new frame in the browser window (below) showing the grid reference plotted as a green square, over a map backdrop. There is the option to either display a Map or Satellite view. Vice-county boundaries are plotted, and the OS version shows them in different (transparent) colours. Mean, minimum and maximum altitude within the grid square defined by the grid reference are shown (highlighted by the red arrow below).
Changing the grid reference to that of the monad, NJ1212, calculates the mean, minimum and maximum altitude for the whole monad.
Note that in this instance the grid reference lookup tool has detected that a very small corner of the monad is within vc94, whereas the 100m grid reference was entirely within vc95.
Find altitudes while searching in the DDb
Altitudes are estimated by the DDb using a very high resolution point altitude GIS dataset.
When logged in to the DDb, when viewing any records in the web browser window, clicking on a site grid reference, opens a new tab with a similar window to that described above.
Including estimated mean altitudes in a download
Estimated mean altitude can be included as a column in a download. Tick the box in the download options screen.
Remember, the mean altitude is calculated for the whole square as defined by each record’s site grid reference. In areas with marked topography, the mean altitude for coarse precision grid references, eg a hectad will not be meaningful. In such situations it will be better to restrict the query, or your spreadsheet analysis, to higher precision records.