Imagery from all these providers can be accessed online in their applications, where you can also access archived imagery through Google Earth historical imagery or the ESRI Wayback app. There are various ways to obtain free high resolution satellite imagery, but here I compare the imagery provided by three of the most common providers Google Earth, ESRI ArcGIS World Imagery and Bing Maps. This makes free high resolution imagery a very valuable resource for the archaeologist, although it does have limitations. Unfortunately, although you can purchase high resolution satellite imagery from various providers, it is often expensive and the contract comes with quite strict restrictions regarding what you can do with it and with whom you can share it. During my recent georeferencing project, it was necessary to use the highest resolution imagery I could obtain to locate the historic maps as precisely as possible.

For some purposes (such as overviews or larger maps) we might only need low or medium resolution imagery, but in many cases high resolution imagery is essential to our research objectives. The resolution of satellite imagery is crucially important to its usefulness to the archaeologist because it directly impacts the features you can see and t he precision with which you can georeference other data.

Google satellite picture of my house