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I have tried to merge my 405 Aerial Photos into one. I have FME and ArcInfo 10.0 at my disposal on Windows 7 64bit.

I have tried the following: create a mosaic; export all images from a rastercatalog; create new empty raster and then loaded the rasters, and in FME I have tried the RasterMosaiker. Everything starts ok, but then due to the file size creates an error after many hours.

Does anyone have any experience creating such large single raster data files and can offer some tips on how I could achieve this,

My only restriction is that I don´t wan´t to decrease resolution.

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  • Have you had issues using the ArcGIS command Mosaic to New Raster (Data Management)? Try writing to a compressed format such as .jp2 rather than .tif. Also, decrease the bit depth from, for example, 32 bit float to 8 bit unsigned. – Aaron♦ Nov 25 '13 at 15:41
  • I have a general suggestion regardless of the tool you ultimately use: for such a large output image consider a format with wavelet compression, e.g. JPEG2000, MrSID, or ECW. – user3461 Nov 25 '13 at 15:42
  • How large are your individual raster images? From the problem you are having, I get the impression that they may be rather large. This then begs the question of what, aside from the ease of loading them in to projects easier, is the benefit to merging them all into one image? What is your end-game here, as that could help guide the suggestions you are given? – Get Spatial Nov 25 '13 at 16:40
  • Are you using FME 64bit? and how much RAM does your local PC have? – Mapperz♦ Nov 25 '13 at 16:47
  • My PC is windows 7 64bit with 4gb Ram. I have 405 Images at approx 300mb each. I need to keep raster images in MSSQL SDE for every 3 years dating back 15 years....so we are talking about 5 complete sets of aerial images for a region of approx 2000 Sqkm. I also have to keep topographic maps for 6 different scales 5000/25000/50000/100000/500000/1000000 - Thus by creating one image for each product I am cutting down the amount of administration considerably. Importing RasterCatalogs with thousands of images would be inefficient in my opinion. – Robert Buckley Nov 25 '13 at 21:07
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Another option is to build a Virtual Raster. You can perform this using GDAL, FWTools, or QGIS. Essentially, a virtual raster will make the mosaic, but as a pointer file, that brings in all the imagery. The file size stays relatively small, and the performance is good. I am using it to mosaic 5cm imagery, and I like the results.

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  • Please don't promote FWtools anymore. It is light years behind the current GDAL version. – AndreJ Nov 25 '13 at 16:06
  • Sure thing. Would MSYS be the preferred commandline tool? – Ryan Garnett Nov 25 '13 at 16:49
  • No, gisinternals.com/sdk provides the most current GDAL version including a command shell for Windows. And it does not harm a working QGIS installation (which FWtools did for me). – AndreJ Nov 25 '13 at 19:14
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FME RasterMosaicker can accomplish this:

You will have to modify these setting to suit your sampling and Interpolation.

enter image description here

You should be be able to achieve something like this if your aerial photo have been ortho-rectified:

enter image description here

It might take a few goes- best advice is to try a sample of 3-5 adjoining images and test.

source of image (safe.com) and more information:

http://docs.safe.com/fme/html/FME_Transformers/Default.htm#Transformers/rastermosaicker.htm

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  • It looks like he has already tried this workflow. I think he is having more trouble with the size and number of rasters he is trying to merge, than with any particular process to perform that merge. – Get Spatial Nov 25 '13 at 16:41
  • Maybe the process needs to be staged smaller jobs rather than one large workspace for all. Asked if 64 bit FME is used and the available RAM will update if have more information. – Mapperz♦ Nov 25 '13 at 16:49
  • I am having problems with the total size I think. I am wondering if my problems are due to the Page file in Windows 7. I assume this is set at 4GB. Would anyone know if this is an issue here? If I tried to do this in an SDE Database, would I have a better chance? – Robert Buckley Dec 23 '13 at 14:06
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    FME creates ffs files in most processes, you should be able to use ALL the RAM on the PC, for Windows 64bit should be able to use up to 192 GB msdn.microsoft.com/en-us/library/windows/desktop/… – Mapperz♦ Dec 23 '13 at 15:11
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In addition to @Ryan Garnett answer, you can convert the VRT file to BIGTIFF using gdal_translate if you absolutely need a unique file (this is often not necessary as most software can read vrt's). Just make sure that you use

gdal_translate -co BIGTIFF=YES -co TILED=YES source.vrt result.tif

if your tif exceed 4 Go

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    Just to add, -expand rgba can be useful if the sources have paletted colours. – AndreJ Oct 16 '14 at 8:41

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