Error while collocation

May I know how to fix this error?

Collocation requires that SNAP recognize the geolocation of each source product. There may be some additional limitations when mixing projections (e.g., Mercator projections with polar projections). Does the problem source product show geolocation when you view it in SNAP or a GIS application? Can you provide more details for the source products?

1 Like

Yes, the projection is traverse Mercator, the datum is D_North American_1983. The first product shown is a PCA on Hyperspectral data containing 50 bands and the other one is a training set which I need to collocate in order to check the classification results. Yes, it is showing the geolocation. btw Is there any collocation tool available in ENVI?



You shouldn’t add one product as master and as slave product. In the best case it only creates too big target product with duplicated bands and in the worst case it can create errors.

In which data format is the “20170218…” product stored.
It could be that sometimes a different reader is used which is does recognise the CRS.

ENVI has for sure a collocation tool too. But I don’t know it.

SNAP being focused on remote sensing it is possible there are some gaps in the support, in which case you may have better results with GIS software. There are, however, many variations of “Transverse Mercator NAD83”. Does your metadata provide EPSG numbers for both files? Here is an example:

CRS Type:	Projected
EPSG Code:	EPSG:26903
EPSG Name:	NAD83 / UTM zone 3N
Datum Name:	North American Datum 1983
Ellipsoid:	GRS 1980
Semimajor Axis:	6378137.0
Flattening Ratio:	298.257222101
Base CRS Name:	NAD83
Projection Name:	UTM zone 3N
Conversion Method:	Transverse Mercator
Parameter: Latitude of natural origin
Parameter Value:	0° 0' 0" N
Parameter: Longitude of natural origin
Parameter Value:	165° 0' 0" W
Parameter: Scale factor at natural origin
Parameter Value:	0.9996
Parameter: False easting
Parameter Value:	500000
Parameter Units:	metre
Parameter: False northing
Parameter Value:	0
Parameter Units:	metre
Axis: Easting
Order:	1
Abbreviation:	E
Units:	metre
Orientation:	east
Axis: Northing
Order:	2
Abbreviation:	N
Units:	metre
Orientation:	north

See EPSG:26903 for more details. If one of your data sets used the outdated NAD27 version and/or provides incomplete metadata, SNAP may not be able to work with the files. A web search may give you some examples showing how to rescue such data.

I abled to collocate the required datasets. The data format of the file- “20170218…” later been switched to ENVI for the ease.

The ESPG is 26915. Problem solved. Thank You.