QGIS Time Manager, for archaeological drawing on RTI-like raster series

Hi all,

I go on today writing about the Time Manager plugin of QGIS we saw in our last post. 

This time I will focus the attention on one of the alternative (and unconventional) use we can do of this tool for archaeological aims: an archaeological vector drawing based on RTI-like raster series.
Of course, when I speak about archaeological vector drawing, I mean a GIS based technique (like the one described in this old post). We already developed a little bit further this methodology in order to use it in a semi-automatic way for archaeological finds (related post 1 and 2; bibliography here), so that this post can be seen as an integration of that work-flow. For the concept of RTI, I suggest you to read +Rupert Gietl 's post about a large scale case of study for such an application and my post about the open source tool developed by Giampaolo Palma (Visual Computing Lab of the CNR-ISTI).
The concept of RTI-like raster series is pretty simple: if in a common archaeological excavation is planned an RTI documentation (e.g. to further analyse particular artefacts such as small pottery fragments, coins, inscriptions in stone, etc...), than it is also possible to use some of the original pictures (with different light conditions) to simulate an RTI viewer within any GIS software. Once one of this picture has been rectified (and georeferenced, when needed), the related worldfile can be used also for all the other images (considering that they have all the same size), so that in QGIS it is pretty simple to create a raster series through the Time Manager plugin.
The video below shows the result of this operation on a pottery fragment from the excavation of Khovle Gora, an archaeological mission in Georgia which we supported for the University of Innsbruck (Institut für Alte Geschichte und Altorientalistik).

I hope this post will be useful, have a nice evening!

Archaeological drawing symbols in QGIS

QGIS style tools for vector layers allow us to build custom symbols for archaeological drawings (plans and sections). In this post I will present some preliminary examples of customizable styles for graphically representing hachures and soil texture (clay, silt, sand and so on). For each, the .qml style files are downloadable from http://www.uselessarchaeology.com/ (section programming): you can put them in your QGIS project and/or add to QGIS style manager for testing and modifying.

Using vector styles makes the drawing more automatic and fast, because is no more necessary to draw manually each individual symbol. Furthermore, vector styles enable to change quickly the size of symbols when the scale changes: in such way there is no need to scale any single object.

The bulding of a new style is managed by QGIS style window: with button “Add symbol layer” is possible to make a new symbol joining 2 or more individual symbols. All symbols settings (dimension, angle, offset, etc.) can be changed in the same window.

Hachures

In plans, the edges of holes and ditches and the differences in level are represented with hachures. They are composed by an isosceles triangle and a line: the triangle marks the highest part of the feature, where the slope begins; the line represents the length and direction of the slope, with the end of the line showing the bottom of the slope. I created 3 different styles of hachure for point layers (hachure_pn), linear layers (hachure_ln) and polygon layers (hachure_pl).

For representing the differences in level, for example at the top of wall, I create a shapefile of points connected to an attribute table with two numeric columns named “angle” and “length”: the first column records rotation angle of hachures, the latter records the length of hachure's lines (where lines are not required, the column value will be always “0”). Then I draw points in the place where there are differences in altitude, I load hachure_pn style, I rotate each points with “Rotate Point Symbols tool” (in advanced digitizing toolbar) and I write the line length I desire in attribute table.

All settings are customizable: from “Marker – Advanced – Rotation field” you can set attribute columns for angle; from “Vector Field Marker” you can set attribute columns for angle and length; from “Simple marker” you can set triangle dimensions and offset: usually I give an offset that is half of triangle dimension for fitting the point to the line.

Hachure_pn style can be used also for linear or polygon features.

If I have to draw a scarp, I create a linear shapefile and I load hachure_ln style. It's possible to modify dimension of triangles, space between symbols, width of line, etc. changing parameters in QGIS style window.

For representing a ditch or a hole, I create 2 polygon shapefiles, one for top perimeter of the feature, one for the bottom limits. The top polygon is drawn by hachure_pl style and the bottom polygon is filled by white color: in the layer tree the bottom polygon must stay over the top polygon for covering the hachure's lines that exceed the slope. Like above, dimensions, space between symbols, offset and so on are editable in QGIS style window.

Soil texture

I post some examples of archaeological layers filled with symbols representing soil components: clay, silt, sand, silt-sand.

You have to pay attention to the settings of the these styles. Many symbols are set in map units and not in absolute measure (i.e. millimeters) to better fit the variation of scale during the display. For printing, all style settings must be changed according to the plot scale; for this purpose printing tests are recommended. Finally, I suggest to export in .svg format and modify the layout in Inkscape for adjusting the last details.

In future I hope to post other examples of archaeological styles. But if you have other ideas or you want to contribute with your personal QGIS archaeological styles, we could create a shared library of archaeological symbols for QGIS.

Denis Francisci

QuantumGIS and OpenJump: Photomapping with more pictures (Corte Inferiore method)

Hi all,
i would like to share a new method to realize georeferenced 2D-photomosaic. Thanks to the new version of OpenJump (r3856), now it is possible to export the GIS-view to any kind of resolution (no more block to 3800 width-pixel). Just set in the oj_linux.sh file (OpenJump bin folder) the allowed memory in the line 24

JAVA_MAXMEM=${JAVA_MAXMEM--Xmx2048M}

with 2048M my computer can export GIS-view till the value of 6905 width-pixel. More memory gives more resolution.

This is the videotutorial:

and this an example:

More info about the archaeological automatic drawing technique

Yesterday I was looking the statistics regarding this blog and I noticed that one of the most popular post is the one about the automatic drawing technique we (Alessandro Bezzi, Simone Cavalieri and me) proposed some years ago. I noticed as well that i forgot to upload in Arc-Team's open library the presentation we did in Foggia (for ArcheoFOSS 5) about this argument (sorry, just in Italian by now...). Now the link is active and you can download the presentation here, or in Academia.edu.
As the slides are in Italian I summarize here the experiment we did in that occasion. We divided archaeological finds in four classes, looking which kind of documentation normally they need.

1) photographic documentation (e.g coins)
2) simple drawing (e.g. flint)
3) drawing + shading (e.g. normal artefacts)
4) drawing + shading + section (e.g. pottery)


Then we developed a five steps techniques to get the appropriate documentation for each class in a automatic or semi-automatic way (using only FLOSS, of course):

1. rectified photo (GRASS - efoto)
2. rectified photo + vector drawing (GRASS - efoto -OpenJUMP)
3. rectified photo + vector drawing + shading (GRASS - efoto -OpenJUMP - stippler -  Inkscape)
4. rectified photo + vector drawing + shading + section (GRASS - efoto -OpenJUMP - stippler - Inkscape - hardware)

Here is an image with the original picture of the archaeological finds we used as test and the final layout.

All the finds come from the excavation in the church of S. Andrea in Storo (TN - Italy) and gave us positive results (I just used to many points in stippler for the drawing of the pottery... anyway it is now easy to change this parameter with the new python interface Alessandro developed).

In the slides you will also find our first test on Lena picture:

The image has nothing to do with sexism, she is just o kind of standard since 70's for raster images tests... by the way she is beautiful :)

2016-04-28 Post updated

In 2010 we wrote an article (in Italian) about this technique:

"Proposta per un metodo informatizzato di disegno archeologico" (here in ResearchGate and here in Academia).

Archaeological drawing from photomapping

IMHO one of the main benefits of photomapping is the fact that everybody is able to do good archaeological drawing. In this way it is not necessary to divide archaeologists between "diggers" (who simply excavate layer by layer)  and "drawers" (who just document). In our (Arc-Team) experience it is never a good solution when someone has to document a situation he does not know (because was exposed by someone else).
In other words, photomapping techniques and GIS allow also normal archaeologists to reach the same quality level of professionals in drawing layers or finds. As an example, the picture below shows the skeleton of a young goat found in Aramus (AM): the georeferenced photomosaic is done with photomapping techniques ("metodo Aramus") and the drawing is done by me (i am not a professional in drawing) using the GIS OpenJUMP (inside ArcheOS).

Georeferenced photomosaic and vector drawing with OpenJUMP

Archaeological automatic drawing

In 2009 we were looking for a system to get a fast and easy way to draw a lot of archaeological finds automatically. Thanks to the help of Simone Cavalieri (who found in internet Adrian Secord's algorythm) we developed a methodology which, combining different Free/Libre and Open Source Software, has speeded up our drawing techniques. The main point of the problem was to get an automatic shading through dots, to respect most rules in archaeological drawing. The solution was the software Stippler, which gave us promising results. In the image below you can see just an example of automatic shading with a test low quality picture of the Venus of Willendorf (downloaded from Wikipedia).

Shading with stippler (stippler-GUI)

2016-04-28 Post updated

In 2010 we wrote an article (in Italian) about this technique:

"Proposta per un metodo informatizzato di disegno archeologico" (here in ResearchGate and here in Academia).