is it possible to georeference MODIS image in ERDAS IMAGINE by using Google Earth as reference image (to select the GCPs)?
of course it is possible - the only rule you have to follow is that you should do the georeference in the native coordinate system of the MODIS image. Practically, if it is in e.g. Albers equal area projection with a certain projection center, map coordinates of your GCPs finally should be in this grid. You can catch GCPs from GE in WGS84 but before the final rectification, they all should be reprojected to the satellite image's native coordsys.
It should be possible. I have tried in ARCGIS and the process would be same. Select GCPs from Google earth image in DD. Identify the same same GCPs in MODIS and rectify.
of course it is possible - the only rule you have to follow is that you should do the georeference in the native coordinate system of the MODIS image. Practically, if it is in e.g. Albers equal area projection with a certain projection center, map coordinates of your GCPs finally should be in this grid. You can catch GCPs from GE in WGS84 but before the final rectification, they all should be reprojected to the satellite image's native coordsys.
Ehab: it is another piece of cake. If you want to rectify aerial photos, ortho-rectification should be used, moreover you are expected to know all optical details (focal length, physical position of the frame signals) as well as a high-resolution elevation model.
There is one consideration to point out if you are going to use Google Earth for georeferencing:
- Google Earth used EPSG:900913 projection rather that WGS84. The Differences are little, however EPSG:900913 is measurable in meters, though the coordinates presentation is in DD.
Ref: - http://spatialreference.org/ref/sr-org/google-projection/
- http://osgeo-org.1560.n6.nabble.com/EPSG-4326-Vs-EPSG-900913-td4661445.html
its better to Georrfrence in ArcGIS, Image to image.. this have more accuracy then Erdas, it Automatically adjust renaming points. Then use this image in erdas.. First add reference image in ArcGIS then add google earth image. Then click on georeference tool and adujst it according to google... thats all..
yes it can be,with the help of Google earth coordinate can be reference any other image,but accuracy should be maintain
Yes it can be done. However I suggest some sort of pre processing /rubber sheeting - That is developing your own georeferenced Google image for area of interest, First thing is select good GCPs first. Then validate them using a standard digital topographic map. This helps in understanding the difference as Google image is not based on WGS 84 system. This difference though small sometimes, is certainly not linear and depends on the type of terrain. Then one can straight use the "Georeferencing verified/validated" [?] Google image for georeferencing of MODIS . Use ArcGIS and process in ERDAS.
I think that for MODIS images is good the resolution of google earth images, but is important to be aware that the coordinates you find in the images of google earth can have an offset with the coordinates in the field. I think that the precision that you need it will depend of the application that you will do to the georeferenced images... Hope this helps!
It should be possible. I had done this process with LISS III image (Spatial Resolution 24m).
Simply you have to change part of Google Earth in which you are interested to UTM of your local geoid datums. Say, Everest 1974 or a more recent one.
Try with
https://www.youtube.com/watch?v=sCtmT0DisVY
For Linking ERDAS Imagine to Google Earth
And in Erdas 2013 for Synchronise Erdas with Google Earth
https://www.youtube.com/watch?v=zanHaeJSV5s
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