WMS CNIG Digital Library

Visualisation service that allows you to visualise original frames of photogrammetric flights made over the national territory. Each layer offers frames of a different flight and each flight has specific flight dates and scale characteristics. These layers allow you to consult the characteristics of the flight and each frame, including its download links. This service also allows you to consult the CNIG Photo Library Archive Database through its InfoFlights layer to obtain the flights available in the CNIG Photo Library Archive that cannot be published through a WMS service, but which are available to the citizen in its service to the public ([email protected]). Historical flight frames have only approximate coordinates at the centre of the frame and most do not have angles of orientation (necessary for positioning the image). For this reason, when viewing the frames with a map or a background image, there may be displacement between the two sources of information. There are also displacements due to the fact that it is a frame and not an orthophoto. PNOA flight frames, although better positioned, suffer from displacement due to the fact that it is a frame rather than an orthophoto. See the frame and orthophoto difference at http://www.ign.es/resources/fototeca/help_es.pdf. The frames of historical flights are the result of the digitisation of the analogue product (negative of the frame), since no digital cameras were used in photogrammetry at the dates on which these flights were made. Historical flights are not fully digitised, alternate frames of each flight have been digitised and there are undigital zones. The frames of PNOA flights cover different areas of the national territory depending on the year of flight, the surfaces flown each year can be consulted at http://pnoa.ign.es/vuelo-fotogrametrico. The access to or connection to this service to obtain the functionalities for which it is intended is free in any case, provided that the authorship of the IGN as owner of the service and its content (which can be stored for private use) is mentioned as follows: “© National Geographic Institute of Spain”. Service WMS 1.3.0 according to ISO 19128:2005.