3.2 Working With Imagery
There is only a limited number of companies/satellites that actually capture most of the available satellite imagery, with many more resellers providing access to and selling imagery. See Wikipedia for a good introduction. When assessing the imagery available for your project, try to look for:
- Freshness (the date of the imagery)
- Resolution
- Quality (color, contract, obliqueness/angle of imagery, lack of cloud cover)
Some useful tools to help in this:
- Visually compare imagery available for use in OpenStreetMap: http://osmz.ru/imagery/ (or from within JOSM)
- To find specific dates/scenes from DigitalGlobe satellites: https://discover.digitalglobe.com/
- To find image metadata on ESRI imagery: https://www.arcgis.com/home/webmap/viewer.html?webmap=c03a526d94704bfb839445e80de95495
