From available imagery to accessible dynamic imagery layers
Having imagery and indices in a digital form makes them available, but not yet easily accessible.
GeoDyn has partnered with Esri and developed procedures to transform the imagery into dynamic image mosaics as image services. This technology utilizes the digital photo indices and scanned imagery to enable users working in a wide range of web or desktop applications to zoom into any location and immediately access all the available imagery. Using only the approximate position that can be expected from the photo index, the positional accuracy of the imagery is initially not very high. Therefore GeoDyn then runs aerial triangulation and block adjustment processes on the imagery. This refines the accuracy and utilizes the dynamic mosaicking and on-the-fly processing capability of ArcGIS Server to provide accurately georeferenced imagery. The digital terrain models required for the accurate orthorectification are either sourced from datasets such as 30m SRTM, from local sources or generated from the triangulated imagery. As required color corrections and seamline mosaicking can be defined and also applied on-the-fly so as to improve the accuracy while not affecting the source or creating duplicates of the imagery. The result is an image service that provides instantaneous access to any of the temporal imagery. Unlike a more traditional process of converting to static orthophoto mosaic, the use of dynamic mosaics ensures the full information content in the imagery is maintained and accessible. If required as background imagery, the static orthomosaics can also be exported as files or served as simple map services.
The conversion of aerial film archives is now fast and affordable. Aerial film archive conversion projects that were slated to take many years to complete can now be completed in a few months. The valuable information presently stored away in inaccessible canisters can soon appear on your screen enabling you to look into the past.