Borealis uses the standard Shapefile structure in conjunction with a projection system (spatial reference system) to place them in the world.
Shapefile stores geometry data and attributes/feature spatial information in a data set. The geometry data is stored as a shape comprised of a set of vector coordinates used to position and draw it on a map.
While organisations and websites can provide a Compressed .ZIP file that meets all the requirements and is ready-to-go, you or a GIS expert may have to review and maybe modify a few things in the .ZIP file to get the desired results in Borealis.
What Should be in your Compressed .ZIP file
Naming Convention of the Files in your .ZIP File
When reviewing or validating a Shapefile Compressed .ZIP file, it is important that the naming structure for each of the file uses the same name (excluding the extension).
For example, your main files could look like this:
- Canada_2024.shp
- Canada_2024.shx
- Canada_2024.dbf
During the importation process, this allows the application to process and read the files, building relations between the data, and output the resulting geographical information onto the map.
Main Files of Your Shapefile
A Shapefile compressed .ZIP file should at the very least include three files with the following extensions:
- A .SHP file: The .SHP file is the main file the stores the geometry information of what you are importing.
- The .SHP file must have a column header named ID to specify the ID of each unique identifier for each individual asset.
- You can also use a secondary column titled COMMENTS to add further details.
- A .SHX file: The .SHX file is the index file that store the index information of what you are importing.
- A .DBF file: The .DBF file is the file that stores attribute/feature information of what you are importing. You can open this file in Excel to review and adjust its content as needed.
Key points regarding the file structure:
- The relation between the records in the .SHP file and the .DBF file is one-to-one and based on record number (position) in the files.
- The list of items (ID column) in the .DBF file should be in the same order as the list of items found in the .SHP file so that they can be linked together by the system during import.
Secondary Files That Can Also be Included in Your Shapefile
The following files can sometimes show up in your Shapefile Compressed .ZIP files depending on how they were generated and their intended distributions. They are sometimes used by specific GIS applications.
Borealis does not use any of the secondary files. Only the 3 main file types are taken into account when importing Shapefiles objects.
- .SBN /.SBX: They store the spatial index of what you are importing.
- .FBN / .FBX: They store the spatial index of what you are importing for shapefiles that are read-only.
- .AIN / .AIH: They store the attribute index of the active fields in a table or a theme's attribute table.
- .IXS: Geocoding index for read/write shapefiles.
- .MXS: Geocoding index for read/write shapefiles (ODB format).
- .PRJ: Stores information about the coordinate system and map projection. Borealis does not use this information and you will have to select your coordinate system upon importing the shapefile.
- .XML: Stores metadata information about the shapefile.
- .CPG: File that is used to specify the codepage for identifying the character set to be used.
What is a Spatial Reference System?
A spatial reference system, or coordinate reference system, is a system that uses abstract mathematics to measure locations as coordinates, thus converting geographical locations on the curved surface of the earth to a flat surface on a map using x- and y- coordinates in feet or meters.
When importing your Shapefile Compressed .ZIP file, if you notice that the spatial reference system is not available from the drop-down list, you can contact our support and ask us to add it.
Notable examples of spatial reference system are the EPSG: 4326 - World Geodetic System 1984 (WGS 84) and ESPG: 3857 - WGS 84 Web Mercator / Spherical Mercator. WGS84 is the spatial reference system used by GPS systems.