Historical aerial photo georeferencing: a crowdsourcing project
Here you see an image of the georeferenced aerial photo mosaic produced at the end of year 2016. This mosaic is composed of 69 aerial photos, with dates ranging from the last quarter of 1950 to the first quarter of 1951. You can browse this and other historic aerial photos and image files at our REST endpoint http://gis.otg.pr.gov/gis_central/rest/services/historic_images
Our goal is to georeference as many aerial photos as possible and all the GIS users in Puerto Rico and overseas will appreciate your contribution. We prefer having your collaboration rectifying aerial photos over flat areas first. Just now with this mosaic, many researchers and students can take advantage of this product as a basic input for their land use change comparisons, agricultural and ecological studies, urban sprawl, among other areas of interest.
To normalize the work, we issued a pdf document that states our requirements to choose your rectified version of one or more of this set of aerial photos.
- Flat or slightly undulated areas: These offer the advantage of being more easy to work.
- Urbanized areas, or historical urban zones over the municipalities.
- Areas dedicated to agriculture activities, sugar cane, pastures, etc.
Some of the requirements stated in the document are:
Spatial resolution: 0.7 meters
Spatial reference system: NAD83(2011) EPSG:6566
RMSE: must not exceed 9.999 meters at flat areas
See the document mentioned above for important details and what map sources to use to perform the rectification.
IMAGE FILES SUBMITTED THAT DO NOT FOLLOW THE GUIDE WILL NOT BE CONSIDERED FOR UPLOADING AND THEREFORE WON'T BE ADDED THE EXISTING MOSAIC
Historic aerial photo image files are available at the following site:
This site has some unrectified, low resolution mosaics that may help you finding your area of interest.
Please contact us (firstname.lastname@example.org) for finished aerial photos, ready to be posted over the existing mosaic. This process could take some time, depending on the requirements: spatial error RMSE, spatial resolution, elimination of black borders, among others stated in the document.