my question is how to go about mosaicking ~120GB, 1200+ tif files into one raster within ArcMap. I am currently splitting up the region in smaller sets and then plan to mosaic all these together to form the one final file at the end. I'm using the Mosaic to New Raster tool. The reason I need a single file is so I can use ENVI classification functions on it.
Does anyone know if ENVI can use an ESRI Mosaic Dataset? Is there a better way to go about this (e.g. file type, etc)? I'm using unsigned 8bit data, 4 band imagery. It's taking a long time and I don't know if ArcMap will even be able to mosaic the total, final file at the end of this. I feel like this is one of those "I don't know what I don't know" problems. What am I missing?
Best Answer
I wouldn't use Mosaic or Mosaic to New Raser, they are slow and cumbersome. Create a Mosaic Dataset then use Copy Raster to export to a single image, this is considerably faster and can be viewed in ArcMap before export to ensure the mosaic is done well before committing to a huge process. I would use either ERDAS Img or GeoTiff as the output format - they can have sizes over 2GB, support multiband and have support for the majority of pixel types.
The Mosaic Dataset is an Esri format, it is unlikely that ENVI (or GDAL, or File Geodatabase Api) will be able to access the mosaic dataset directly but they export fairly quickly.
ENVI should be able to access a virtual raster which does not duplicate the rasters or mosaic but rather sees them as a tile set (much like a mosaic dataset)... Esri will be able to read a VRT but is significantly slower than a mosaic dataset to refresh.
If you have GDAL you can use GDALbuildVRT to create a virtual raster and then GDALADDO to add pyramids (to make it quicker to view).