X
PrevPrev Go to previous topic
NextNext Go to next topic
Last Post 18 Mar 2011 11:28 AM by  anon
Problems with calibrating a SPOT file
 2 Replies
Sort:
You are not authorized to post a reply.
Author Messages

anon



New Member


Posts:
New Member


--
18 Mar 2011 11:28 AM
    I'm using the spot_calibrate.sav tool and can't get it to work. I import my DIMAP through open external file>SPOT>DIMAP using the .DIM. But when I try to use the tool I get an ENVI warning "File is not a valid SPOT DICOM sensor type". In my header the sensor type does not seem to be included and is stated as unknown by default. When I change the sensor type to "SPOT" through ENVI and try the tool again I get the prompt for the .DIM file but then ENVI freezes. I'm using ENVI 4.6.1, spot4 images that have been orthorectified (not by me) and the units are "equivalent radiance (W.m-2.Sr-1.um-1)". Does spot_calibrate.sav support ENVI 4.6.1? I'll post a copy of the .DIM Thanks. DIMAP 2010 2010 SPVIEW_FINLAND FINLAND FINLAND FI Spot Registered Product,© CNES 2010, © Metria 2010 Metria Kiruna, Sweden 2010-12-10 CBCG1R20N 467510 SPACEMETRIC Number of control points SPACEMETRIC:NGCP 17 Root Mean Square residual error X component SPACEMETRIC:RMSX 4.44 Root Mean Square residual error Y component SPACEMETRIC:RMSY 4.87 ORTHO, Ortho corrected imagery with DTM (25 meters grid) All radiometric processing performed before any geometric correction EPSG EPSG:2392 PROJECTED KKJ / Finland zone 2 2486400.0 6896800.0 20.0 20.0 CELL 2505432.284838 6896790.0 2486519.007711 6839912.641602 2544936.362305 6822476.113281 2563866.933594 6879400.096436 2505447.020554 6896790.0 8 BYTE I GEOTIFF 3880 3720 4 1 XS3, Near Infra Red (NIR) 3.008095 0.0 equivalent radiance (W.m-2.Sr-1.um-1) 2 XS2, Red 3.982083 0.0 equivalent radiance (W.m-2.Sr-1.um-1) 3 XS1, Green 2.897552 0.0 equivalent radiance (W.m-2.Sr-1.um-1) 4 XS4, Middle Infra Red (MIR) 12.034068 0.0 equivalent radiance (W.m-2.Sr-1.um-1) 1 2 3 0 nodata 1 -21.176669122453205 201.4188379566465 35.28826057891525 92.52268350961744 5.0 255.0 2 -51.10995510167695 148.13751948526223 33.42788970487861 80.41972430748243 31.0 255.0 3 -30.9534029696878 175.47146389994356 19.366494480711214 85.75296347620852 53.0 255.0 4 -52.321192588238816 276.91685620990523 39.35717627644092 69.89694054046836 1.0 255.0 40702231005030936482I0 EPSG EPSG:2392 PROJECTED KKJ / Finland zone 2 2505433.614142 6896793.99379 2486519.008112 6839912.639815 2544936.361776 6822476.114073 2563866.936299 6879400.098634 SPOT 4 HRVIR 2 2010-05-03 09:36:48 070-223 0 -5.85345543732 166.07897996 42.992890409 20.0 SPACEMETRIC Number of control points SPACEMETRIC:NGCP 17 Root Mean Square residual error X component SPACEMETRIC:RMSX 4.42 Root Mean Square residual error Y component SPACEMETRIC:RMSY 4.87

    MariM



    Veteran Member


    Posts:2396
    Veteran Member


    --
    18 Mar 2011 01:08 PM
    Your DIMAP file does not look like an original DIMAP file from SPOT Image. It has a lot of different information and is missing some necessary information. It looks like it was processed in another system (Spacemetric) that outputs its own DIMAP format file. For example, in a sample 2A format SPOT DIMAP file, you have the Solar irradiance value, which is used in the reflectance calculation: 1843 Your dimap file does not have this for any band. The sun_elevation is also recorded differently. In a 2A file it looks like: +3.6441070041e+01 but in your file it looks like: 42.992890409 Since the SPOT_CALIBRATE tool looks specifically for these values and expects them in a certain format, it is failing to find the appropriate values in your DIMAP file. In addition, your file has the following statement that other SPOT dimap files do not: All radiometric processing performed before any geometric correction So you might want to contact the data provider to ask how the conversion to radiance and/or reflectance can be done on this file. It is likely a simple equation but you just need to know exactly how it should be performed.

    Deleted User



    New Member


    Posts:
    New Member


    --
    19 Mar 2011 08:06 AM
    Thanks Mari, that makes a lot of sense. I'll get in touch with my provider. But thanks for the quick reply saves me a lot of frustration trying to make them work as they are.
    You are not authorized to post a reply.

    Forums Products ENVI