organisation	MLURI
user_name	David Miller
user_organisation	Macaulay Land Use Research Institute Craigiebuckler Aberdeen united Kingdom AB15 8QH
date	8/7/97
data_set_name	Cwm berwyn, Orthophotograph 1992
data_date	June 1992
description	Digital orthophotograph of the Cwm Berwyn study forest, derived from colour 1:10 000 aerial photography, June 1992. Orthophotograph is panchromatic. Horizontal resolution is 1m.
raster_vector	RASTER
filename	cwmberwyn_ortho_92.img
software	Erdas Imagine, V8.2, OrthoMAX module (from Vision International)
formats	Erdas Imagine (*.img), Erdas (*.lan), ESRI ArcInfo GRID.
operating_system	Solaris 2.4 and 2.5
format	Erdas Imagine (*.img)
projection	United Kingdom Ordnance Survey National Grid, Modified Transverse Mercator, Airy Spheroid 1838 Central meridian: 2 degrees west Origin of grid: 49 degrees north Scale factor at central meridian: 0.9996 False easting: 400000m False northing: 100000m
data_quality	YES
resolution	Horizontal resolution: 1m x 1m. Aerial photographs from which orthophotographs were produced - 1:10 000, scanned at 800dpi (0.32m ground equivalent). Horizontal resolution of DEM used in creation of orthophotographs: 1m x 1m.
attributes	Digital data is 8 bit (1 - 255), single band. Digital values relate to the reflectance of the ground features at time of photograph.
methods	Orthophotograph created for each of three stereo models. Planimetric accuracy: RMS 1m. Ground control provided by GPS (MidasII) with RMS of 0.3m. Orthophotographs clipped with reference to the DEM and subsequent images mosaiced.
other	The orthophotographic image is a mosaic of three orthophotographs, one for each of the component stereo models. The images have been mosaiced with a minimum of photographs used (i.e. the same photograph used for adjacent models) and a minimum of overlap between adjacent images. The objectives were: 1. consistent geometry across the entire mosaic; 2. consistent in visual appearance across the entire mosaic. These objectives were partially successfully, however, the quality of the original photographic images was not consistent and the range in contrasts is low, particularly in the central area of the entire orthophotograph.
copyright	Copyright lies with Macaulay Land Use Research Institute, Aberdeen and the Forestry Commission, Edinburgh.
contact	David Miller Macaulay Land Use Research Institute Craigiebuckler Aberdeen AB15 8QH Tel: +44 1224 318611 x 2240 Fax: +44 1224 311556 Email: d.miller@macaulay.ac.uk