Can anyone help me in generating DEM without using GCPs? I have stereo satellite data and I want to generate a DEM but no field based GCPs are available. Which Software will be best for this job? What will be the accuracy of the DEM generated?
The absolute accuracy of your geolocation will depend on the type of satellite data that you have in hand. For instance, in 90 % of the case you have an accuracy of 15 m with Ikonos and 6.5 m with Pléiades. I assume that you work with VHR images, because otherwise you could use the SRTM and mainly VHR satellite offer stereo acquisitions.
Note that if you don't have GCP, you can still perform the relative orientation of your satellite data, and the relative accuracy will be quite good. Also note that you could try to find GCP from Google Earth or Bing map or Open Street map, but the accuracy of those datasets may vary a lot depending on your study area.
In terms of software, you have several commercial softwares ( Leica Photogrammetry Suit, ENVI DEM Extraction, PCI Geomatica) or open source softwares (MicMac, Orfeo Toolbox)
Reet you can easily generate DEM using PCI geomatica orthoengine. I can send you a complete procedure to do so. But there is no means to do an accuracy assessment without GCPs. You can use some reference by geocoding the DEM with a geocoded mother image.
The absolute accuracy of your geolocation will depend on the type of satellite data that you have in hand. For instance, in 90 % of the case you have an accuracy of 15 m with Ikonos and 6.5 m with Pléiades. I assume that you work with VHR images, because otherwise you could use the SRTM and mainly VHR satellite offer stereo acquisitions.
Note that if you don't have GCP, you can still perform the relative orientation of your satellite data, and the relative accuracy will be quite good. Also note that you could try to find GCP from Google Earth or Bing map or Open Street map, but the accuracy of those datasets may vary a lot depending on your study area.
In terms of software, you have several commercial softwares ( Leica Photogrammetry Suit, ENVI DEM Extraction, PCI Geomatica) or open source softwares (MicMac, Orfeo Toolbox)
Thanks Saif and Julien. I will be in touch if need further help.
Thank you.
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