(a package of several separate files)
.shp gives features their geometry (points, lines, polygons)
.shx is a mandatory Esri and AutoCAD shape index position file
.dbf is a mandatory standard database file used to store attribute data and object IDs
.prj contains the metadata associated with the shapefile's coordinate and projection system
.sbn is an optional spatial index file that optimizes spatial queries
.sbx are similar to .sbn files in which they speed up loading times. It works with .sbn files to optimize spatial queries
.cpg are optional plain text files that describe the encoding applied to create the shapefile
|Esri File Geodatabase
|.gdb is folder containing all the files of the geodatabase
|.gpkg is a open source (SQL lite) package format for sharing geodatabase files
|.qgs and .qgz (zipped)
|Keyhole Markup Language
|.kml and .kmz (zipped) files were originally developed for Google Earth and are now an Open Geospatial Consortium standard.
.tiff is the raster (image) file
.tfw is the text file accompanying the .tiff that includes the georeference information
Georeferencing is the process of associating a raster map (an image file) with a known geospatial coordinate system. You might think of this as "pinning" a map image in place on top of a larger map grid with latitude and longitude points. Georeferncing is often of a part of working with historic maps in order to compare them to present-day geographic features.
Adding your own data (whether from a non-GIS database, your own original research or from some other source) is a common objective of many GIS applications.
The best approach may depend on the specifics of your data, but we have created a general-purpose set of instructions in this guide.