Reproject raster catalog - ArcGIS 9.3/FME 2012

Question

I have a couple of raster catalogs in different file geodatabases and I need to re-project them to a new coordinate system. Now there is no option to project a whole raster catalog, nor can I use the 'Project Raster' tool, as it won't accept a raster catalog as file type (for selecting single rasters within the catalog).

There are two options that I thought about so far:

• use tool 'Raster Catalog to Raster Dataset', reproject the raster dataset and bring it back into a catalog. Now the problem is on the one hand that this process takes ages (incl. building of pyramides + calculating statistics) and I loose the single items within the raster catalog (after loading the dataset back into a raster catalog), as it just mosaics the datasets together.

• use Python and loop through raster datasets in raster catalog and reproject them individually. I have not investigated this version, but I doubt whether that will work. In case it would, that could be a solution. Anyone did something like that before?

My question therefore is, whether there is a proper/efficient way of reprojecting a raster catalog or the raster datasets within a raster catalog respectively from one coordinate system to another? I basically want to end up with raster catalogs that look exactly as the originals (incl. file names of raster datasets within them), but they do need to have a different projection.

Any tips appreciated as my problem is quite urgent!

UPDATE:

I have access to FME 2012 now, never used it before though. Does anyone have an idea whether this exercise could be accomplished using FME? (it looks like FME can only access SDE raster catalogs, so that may not be the full solution either..)

Answer 1

In my experience, your only option is to mosaic all the datasets in the raster catalog first, reproject the mosaic, and then retile the mosaiced raster. The reason for this is because if you reproject the individual raster datasets, you will end up with black stripes (nodata strips) on the edges of each tile.

FME will handle the file size of the mosaiced raster much better than ArcGIS will, but FME does have a little bit of a learning curve. I like to think of it as ModelBuilder on steroids.

Another tool I have used to mosaic rasters is in the GDAL Library and is called gdalwarp. gdalwarp will allow you to mosaic and reproject all in one step. If you're not familiar with GDAL, it is a free open source library for raster analysis and is available in 64bit, so it can be much faster that ArcGIS.

In order to retile after the mosaic, I would create a polygon index feature class from the raster catalog, reproject the index feature class, and then use it to retile the mosaiced raster. I've typically used Python to retile by simply using a cursor to loop through the index feature class and using the clip tool and ArcGIS to clip the mosaiced raster by each feature.

Hope this helps.