The Location worksheet
All locations used in your data worksheets need to be listed in this worksheet. By location, we mean the common frequently used areas in which research has happened at SAFE. You might have more detail about the precise place you worked in your dataset - great! - but using these known locations allows us to get broad spatial data on sampling relatively simply.
So, we expect you'll have a set of location names in your data sheets, all of which should appear in this worksheet. The worksheet must have the following structure
|My_transect_1||Yes||NA||NA||Linestring||Linestring(117.7762 4.9576, 117.7862 4.9676)|
The location names are checked against the location names known in the SAFE gazetteer. You can look at the gazetteer webpage to see the available sites and to download location data:
You can download the gazetteer locations from the URL above, but if you want to get a list of valid location names for use in a program or script, then we also provide a web service that returns a list of valid names as a JSON object:
For example, in R:
> library(jsonlite) > locations <- fromJSON("https://www.safeproject.net/call/json/get_locations") > str(locations) List of 1 $ locations: chr [1:2691] "SAFE_camp" "Flux_tower" "A_1" "A_2" ...
If you only use known locations, then you only need to provide the location name column.
If your data comes from genuinely new locations or uses a new sampling structure (e.g. a grid or transect), then you can create new location names and include them in your locations table. If they become commonly used, we may consider adding them to the Gazetteer.
If you include new locations then you will need to include the following columns in your Locations worksheet:
New: This should simply contain Yes or No to show which rows contain new locations. You must enter 'No' for known locations and you cannot create a new location with a name that matches an existing location in the Gazetteer.
Type: This is mandatory and is just an indication of the kind of sampling location: 'point', 'transect' or 'area' (or the more GIS names of 'point', 'linestring' or 'polygon').
Latitude and Longitude: these should provide GPS coordinates for the new site. These must be provided as decimal degrees (not degrees minutes and seconds) and please provide 6 decimal places in your coordinates. This level of precision is around ten centimetres and, although the GPS from the field is highly unlikely to be accurate to this level, we want to record as much sampling precision as possible.
Note that you can provide a simple latitude and longitude for any location type: you might not have the coordinates of the whole transect but can give a start point. Any information is better than none but if you don't have any data, then you can enter NA.
WKT: This optional field can be used to provide GIS geometry data for the location in the well-known text format. This is a good way to provide precise GIS data for a location.
Note that these extra columns can be left empty for known locations as in the example above, but for new locations, please explicitly enter NA in these fields.
Location aliases and extending the Gazetteer
In addition to the canonical location names, we also support a set of location aliases. Although we prefer the canonical names to be used, aliases can be used instead: an example is that "463" is accepted as an alias for the sampling point "OG3_463".
The list of aliases also allows us to adopt new locations into the Gazetteer. If you have sampled at new locations that seem likely to be the focus of other research projects then they may be added to the Gazetteer so that other researchers can use them as known locations. We can then use the location aliases to record that 'New' locations in a published dataset have been adopted: for example that the new location "river23" in dataset 123 is the same as the Gazetteer entry "RIVER23".
We prefer GIS information as Latitude and Longitude or WKT because we can use it to add to the spatial index of the datasets, but you can also submit GIS files as external data files alongside your Excel data. You can even include metadata about vector data attribute tables as part of the Excel file.
My data doesn't include any locations
You don't have to include the Locations worksheet, although it would be very unusual to omit it. Possible examples:
- You are working with lab data (and don't need to say where specimens came from in the field)
- You are collecting data haphazardly from across the landscape, for example tracking animal movements, and the data isn't tied to particular sampling locations. We would then want GPS data for each observation!