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I have a large collection of geological maps, scanned in format .jpeg, that cover an important region. Each original map's dimensions are 100cm length by 50cm height.

Analyse map by map all these datas makes very difficult to construct something like a big picture of the situation.

Is there any tool that I can use to assemble all these maps in a single big one on which it could be possible to navigate, to zoom and unzoom, etc?

In other words, I'm looking for some way to convert my database in something like a google map.

After a few searches, something like image pyramids seem to be a good solution for visualizing my maps, but how can I construct the pyramids with so many initial images ?

And after, which tool can I use to visualize the pyramids ?

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    Are the images georeferenced? – Alex Leith Feb 16 '17 at 23:01
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    This question is not answerable in its current format: you need to specify the software you would like to use. It would also be helpful to know the map projection, coordinate system and whether you know the coordinates of any of the points on the maps. It should be doable - virtual layers in QGIS as a start – George of all trades Feb 16 '17 at 23:01
  • @AlexLeith No. I just know which map is the first one and after the succession of maps. All the maps finally make something like a big checkerboard. – P.-A. Feb 16 '17 at 23:08
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    You will need to georeference the images first. As these are geological maps are they depicting large areas? This may make knowledge of the projection system used vital? Do you know their scale? – George of all trades Feb 16 '17 at 23:11
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There is nothing that will automatically do what you want.

You could load all your images in Photoshop or GIMP and overlay them and line them up by hand. This wouldn't have any location characteristics.

You could georeference each one individually somehow, either by knowing their extents and doing it programmatically or manually. And once you've done that you can load them all into a desktop GIS at the same time. You could also mosaic them using this.

Regarding your question about pyramids, this is a method of making viewing a single large file faster by creating low-resolution versions of the image for when you're zoomed out. This won't help you yet!

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You need to geo-reference your images to mosaic them. This could involve a lot of work as it is likely to require manual intervention. This can be done in qgis (Raster > Georeferencer) or by creating external reference files. See this question: How to batch-process georeferencing of rasters (prelude to animation)?

When you have geo-referenced your files, you can use gdal tools to create a mosaic http://www.gdal.org/gdaltindex.html or virtual raster http://www.gdal.org/gdalbuildvrt.html

These tools can be activated through the raster menu in qgis (Raster > Miscellaneous), but they run much faster from the command line.

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