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I am trying to make a batch model to convert band 2 and band 1 MODIS 8 day composites into NDVI. The input files are in tif format, but I want the output to be saved in Idrisi .rst format.

I am using QGIS 2.2 64 bit on a Windows 8.1 machine. I installed via the OSgeo4W, and installed everything, so I am using the Orfeo-toolbox for the raster calculator. I am new to QGIS and not very experienced in python either.

The simple model is presented below. Ultimately, I want to batch this, but for the time being I’m just testing to see if I can get a simple model to work. I have tested the data, using the raster calculator directly in QGIS to make an NDVI and this worked without any problems. I just have a lot of images I need do this for....

![screen capture of mode in QGIS][1]

Below I have copied the OTB execution command and the execution console output from QGIS.

My questions are:

What does it mean that I am missing mandatory parameter “il 0”?

Is there a better way to make NDVI images than using the model I have made?

Any help or advice on this matter is greatly appreciated!


OTB execution command

C:/OSGEO4~1\bin\otbcli_BandMath -ram 128 -exp (NIR - RED) / (NIR + RED) -out "C:/8day_NDVI/NDVI_1.rst"


OTB execution console output

ERROR: Missing mandatory parameter: il 0

ERROR: Troubles loading parameter, please check your line argument...

This is the BandMath application, version 4.0.0

Perform a mathematical operation on monoband images

Complete documentation: http://www.orfeo-toolbox.org/Applications/BandMath.html

Parameters:

-progress Report progress

MISSING -il Input image list (mandatory)

-out [pixel] Output Image [pixel=uint8/uint16/int16/uint32/int32/float/double](default value is float) (mandatory)

-ram Available RAM (Mb) (optional, off by default, default value is 128)

-exp Expression (mandatory)

-inxml Load otb application from xml file (optional, off by default)

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I think I can answer my own question.

It might be a bug. In searching on the internet, I found this link:

http://hub.qgis.org/issues/9317

where someone is having a similar issue using OTB band math in QGIS version 2 via sextante. It says in the link that this is apparently only a problem for 64 bit versions. I had version 2.2 which does not have sextante, but I did uninstall the 64 bit version and installed the 32 bit version (via OSgeo4W), and it still didn't work.

Then looking through the GRASS tools I found "r.mapcalculator" and there everything worked great and easy, including batch processing.

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