Georeferencing oblique photographs

Question

I have a series of oblique photos taken from an airplane of oyster beds that need to be mapped.

Does anyone have any tips on georeferencing oblique images?

I have access to ArcGIS and ENVI.

Answer 1

Oblique photographs, as most of aerial photos, CAN NOT simply be georeferenced. That's because they are perspective projections and as such they MUST be ortorectified in order to be used as maps surrogates. For that you may use a reliable DEM and ortorectify each photo individually or, in case you have stereo-pairs, you can use a photogrammetry software for restitution. The Leica Photogrammetry Suite (LPS) has all the tools you need to perform those tasks.

Answer 2

ENVI includes an Orthorectification module which should be able to do the trick. GRASS can also perform orthorectification, the GRASS book provides a sample chapter which includes both a solid introduction to photogrammetry and step-by-step instructions on the process within GRASS GIS.

Answer 3

1.) You could try Map Rectifier — "From MetaCarta Labs" http://labs.metacarta.com/rectifier/ which allows you to download the warped image as a GeoTIFF.

2.) Or you could download QuantumGIS (QGIS) and install the Georeferencer plugin http://gis-lab.info/qa/qgis-georef-new-eng.html . Good luck!

Answer 4

We describe a method using GRASS GIS (http://grass.osgeo.org/) using orthorectification in this paper:

M. Neteler, D. Grasso, I. Michelazzi, L. Miori, S. Merler, and C. Furlanello, 2005: An integrated toolbox for image registration, fusion and classification. International Journal of Geoinformatics, 1(1), pp. 51-61 (PDF)

Answer 5

You may find this useful: http://www.meteoexploration.com/products/monitoring.html still, you need a high quality DEM