A projected coordinate system tells the data how to draw on a flat surface and sets the units (in this case meters) on which all calculations of distance and area are based. Other grids might have different extents, resolutions and CRS, but those grids will be transformed to whichever study region grid you select. Keep in mind most occurrence data in global data sets will be in degrees latitude and longitude in a specific Geographic Coordinate System (usually WGS 84). This may need to be converted into EPSG:3577, if that is your study region grid’s CRS, in order to overlay it onto your projected grid. This conversion involves transforming each latitude and longitude in degrees, to an easting and northing in meters, in the correct zone within Australia. Biosecurity commons assumes uploaded coordinates are in WGS 84, latitude & longitude, and does the conversion for you if required.
Data that has not been projected (data with a Geographic Coordinate System) uses degrees latitude and longitude to inform where on the earth different features are located, however, it is representing where things are on a sphere (depending on what Geographic Coordinate System was used). Any time you plot a map that has a geographic coordinate system, it will plot using a projection, but because it is measured in angular units (degrees), the simple grid that is presented distorts the size of areas, angles, and distances, so it is useless for measuring distances, areas, or any spatial relationships. Keep in mind that the same Latitude and Longitude will plot to somewhat different locations in Australia if the latitude and longitude were calculated using different coordinate systems. The World Geodetic System 1984 (WGS 84) is the main coordinate system used throughout the world, however, because the world is not a perfect sphere Australia uses a different coordinate system. All data from the Atlas of Living Australia and GBIF are provided in WGS 84, which is also the system most GPS devices use throughout the world. There are many point data and other spatial data in Australian databases that are in a coordinate system such as an Australian Geodetic Datum (AGD). If you used identical latitudes and longitudes, but different coordinate systems, the point locations can plot to locations that are up to 200m apart.
Again, all latitude and longitude data uploaded to Biosecurity Commons will need to be in a WGS 84 CRS, with lat/lon in decimal degrees. Other spatial data will need to include information on its CRS so it can be transformed to match the study region CRS you selected. Raster data that is uploaded will need to be in GeoTiff format with the CRS defined in the file you are going to write.
Raster data that you upload will need to be in GeoTiff format with the CRS, extent and resolution defined in the file you are going to write.
Coordinates that you upload will need to be in decimal degrees (WGS 84, EPSG:4326) and the column headings will have to be lat and lon in a table that is saved in CSV format.
lat lon
-27.38888 152.87777
-27.38788 152.87888
There are many other options besides the 1km2 raster of Australia to select your study region:
• Choose a raster from your other results
• Explore datasets you have previously uploaded or imported, found under “My Datasets”
• Explore thousands of curated datasets
• Import / upload data