Turning GeoTIFF into TIFF + worldfile (QGIS)

hi all,

after some weeks I go on with the videotutorial from the Project Tovel. Until now we saw how to download some Open Data for our GIS, how to load georeferenced raster level in QGIS, how to georeference historical maps.

Today I will show something particular, that probably many of you will not need very often working on landscape archaeological project, but that will be more important to manage excavation GIS: how to turn a GeoTIFF picture into a TIFF + worldfile image.

As some of you will know a GeoTIFF is a particular kind of raster data in which the georeferencing values are embedded within the TIFF itself. This option can be a nice solution for a topographer but it is extremely annoying for archaeologists. The reason is simple: topographers often work on pictures or maps that are ready to be used, without the necessity of any photo-editing, which (on the contrary) is an important phase in archaeological photo-mapping process (e.g. for the "Aramus method"). The primary difference between a GeoTIFF and a TIFF + worldfile image is that it is not possible to modify the first one without loosing the georeferencing values (which are integrated in the picture), while it is possible to perform some photo-editing operations (change the colors, balance the brightness and contrast, etc...) in the second one, without problems, being the geolocalization data stored in a separate file (the worldfile).
For this reason working with raster images and worldfile is often the best choice for archaeological GIS (especially for excavation), where it can be useful to "erase" all the part of the photo which are outside the area of interest (e.g. outside the rectification region) and to take advantage of transparency in overlapping different raster levels (which can correspond to different stratigraphic levels).
As I wrote previously, the videotutorial I prepared using the data of Project Tovel simply shows how to turn a GeoTIFF, currently the unique option for QGIS georeferencing module) into a TIFF and a worldfile, a more useful format, without exiting the software.

Have a nice day!

OpenJUMP: adding a vector layer with a customized db

Hi all,

today I recorder a fast videotutorial regarding the GIS OpenJUMP (which is one of the Geographic software integrated in ArcheOS).

Normally, when you add a new vector layer in your project, you get a new empty level, without any database schema, so that you can start to draw your feature, but, if you want to add some info, you have to manually describe your db schema, like in the video below:

Of course, if you have to draw many different layers with a common database schema (like always happen in a normal archelogical GIS), this operation can be time-consuming (and boring). For this reason in the videotutorial below I try to show how to write a short script which automatically add in OpenJUMP a new vector layer with a customized database schema:

Since I fear the quality of the video is too poor in Youtube, I prepared an image in which you can see better the source code of the script:

The code of the script

To work correctly, the script has to be placed in your OpenJUMP folder, in /lib/ext/BeanTools/ and, as you see in the video, you have to refresh the menu in OpenJUMP (Customize --> BeanTools --> RefreshScriptMenu) to find it (in ArccheOS Caesar you will find the script already in the menu. Just modify the code according to your needs).

Like always I added the tutorial in our ArcheOS wiki (DADP project), in order to go on in composing a free documentation system for Digital Archaeology: 

• Tutorial 1
• Tutorial 2

I also uploaded the code of the script into a specific github repository, so that, if you want, you can contribute in its development. We can use the comment space of this post for the discussion about the schema and about its possible modifications (or you can simply download the script and modify it in order to fulfill your specific needs).

I hope it was useful, have a nice day!