These are the most common types of files you will see described as "geospatial" data.
| Vector | ||
| File type | File extension(s) | |
| Shapefile (a package of several separate files) |
Mandtory 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 Optional files .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
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| Esri File Geodatabase | .gdb is folder containing all the files of the geodatabase | |
| Geopackage | .gpkg is a open source (SQL lite) package format for sharing geodatabase files | |
| QGIS | .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. | |
| Raster | ||
| File type | File extension(s) | |
| GeoTIFF |
.tiff is the raster (image) file .tfw is the text file accompanying the .tiff that includes the georeference information |
There are many more file types that can be used on GIS platforms. The Wikipedia entry on GIS file formats has a fairly extensive list, and Esri documentation can provide more information about their proprietary formats.
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.
You may want to add your own original data to your GIS project.
If you have gathered data (in a spreadsheet, for example) that has conventional addresses, you can visualize those as points on map through a process called "geocoding." Geocoding turns an address into a latitude-longitude coordinate pair that the GIS can interpret.
We have a short guide for adding your own data to an ArcGIS Online map, and there is additional documentation from Esri on geocoding.
Another way to add your own data to a GIS is through the use of field mapping applications.
Esri has two mobile applications that integrate with the ArcGIS platform to gather geo-located data while doing field research.
Survey123 is a straightforward data collection mobile app that creates forms that anyone can respond to on their mobile device. This is useful for gathering information from the public or citizen-science type projects -- anyone can submit information online and they don't need ArcGIS Online access.
Field Maps is the more full-featured mobile application. You will need to be logged in to your ArcGIS Online account to gather data in Field Maps.
Both of these apps will store data as ArcGIS feature layers that you can visualize and manipulate within ArcGIS Online or ArcGIS Pro. You can download the apps from the Google or Apple store (depending on your device type) and log in with your Claremont Colleges credentials.
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| Esri Field Maps | Esri Survey 123 |
