[GIS] Reproject raster catalog – ArcGIS 9.3/FME 2012

arcgis-9.3coordinate systemfmeraster-catalog

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..)

Best Answer

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.

Related Solutions

[GIS] Repairing paths of unmanaged raster catalog in file geodatabase

Based on your edit to your question, it looks like you need to parse out parts of the old path to build the new path. How about splitting up the old path into a list, then building the new path with parts of that list:

>>> import os
>>> old_path = "\\dgdbimg\EGD\Data\DTED_2"
>>> old_parts = old_path.split("\\")
>>> old_parts
['', 'dgdbimg', 'EGD', 'Data', 'DTED_2']
>>> new_path = os.path.join("C:\WorkSpace\Andy3", old_parts[3], old_parts[4])
>>> new_path
'C:\\WorkSpace\\Andy3\\Data\\DTED_2'
>>>

EDIT:

Have a meeting in a few minutes so quickly - here's what I'd do. Either manually push the dbf to a file geodatabase table or do it with code, then loop through the records of the table, and for each one use the parts to build the new path, then call the Repair Raster Catalogs Paths tool. Some psuedo-code:

push dbf to FGDB table (may be a tool to do this? or just do it manually in ArcCatalog)
loop through records in table
    parse out old paths parts
    build new path
    repairRasterCatalogPaths_management()

Here is real (untested) code to try:

import arcpy
import os

arcpy.env.overwriteOutput = 1
arcpy.TableToTable_conversion("C:/Temp/CatalogPaths.dbf", "D:/target.gdb", "DbfToTable")

rows = arcpy.SearchCursor("D:/target.gdb/DbfToTable")
for row in rows:
    old_path = str(row.getValue("Old_Path_Field"))
    old_parts = old_path.split("\\")
    new_path = os.path.join("C:\WorkSpace\Andy3", old_parts[3], old_parts[4])
    arcpy.RepairRasterCatalogPaths_management("RepairRC.gdb\\Unmanaged", "FIX", old_path, new_path)

FME – How to Read Files One by One

I would second @Mapperz comment about upgrading - FME 2012 SP2 contains some significant improvements. If you have a current active maintenance contract then you can download the latest version direct from Safe Software.

As is always the case there are several different ways you can achieve the right result using FME. Here are two approaches you could consider:

Approach 1: MS-DOS Batch Script

When you run a workspace from within FME Workbench what you are actually doing is executing the command-line fme executable. Armed with this knowledge it is straight forward to execute a workspace from the command-line, in fact FME Workbench makes it even easier for you as the top of the log in the log viewer panel will display the command-line to use if you want to execute the workspace from a DOS prompt.

Using that information you can create a batch file to scan a directory of files and then send them one-by-one to FME for processing. For example:

SET FME="C:\Program Files\FME\fme.exe"
SET SOURCE_DATA_DIR="D:\Temp"
SET FME_WORKBENCH="YourWorkspace.fmw"
REM Set any other options here

FOR %%A IN (%SOURCE_DATA_DIR%\*.xml) DO (%FME% %FME_WORKBENCH% --SOURCE_FILE %%A)

Obviously you will need to adpat this to your needs but use the output from running your workspace in FME Workbench as a guide.

Approach 2: Controller Workspace

An alternative approach is to use a controller workspace to execute another workspace repeatedly based on some input. In this case the input will be the path to an XML file. This is straight forward to setup, all you need is a Files and Directories reader and a WorkspaceRunner transformer. An example of how this would look in FME Workbench below:

Example of a controller workspace

An extremely useful resource for all things FME is the FMEpedia site. Lots of examples and help doing all maaner of things with FME.

Best Answer

Related Solutions

[GIS] Repairing paths of unmanaged raster catalog in file geodatabase

FME – How to Read Files One by One

Related Question