S.A.U. Download (1,56 Mb)
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S.A.U. was developed for archaeological intersite studies. However archaeology is not the only discipline that study point distribution maps. This tool will help everybody that has to deal with point pattern analysis.
We appreciate your questions, comments and feedback. Feel free to contact us at this email: macchi@unisi.it
Thank youThe study of the distributive characteristics of settlement patterns is one of the most important topics in the reconstruction of historical landscapes. Unfortunately, advanced knowledge of GIS techniques, as well as quantitative techniques and methods are required in order to achieve positive results in this area. Furthermore, the application of spatial analysis in the archaeological research requires a large and expensive investment of software and hardware to accomplish such tasks. In order to address all these issues, this year we started the development of an analytical tool for the study and analysis of spatial distributions. This software rather than a GIS application shall be conceived as a general utility for data processing. In fact, the main aim of Spatial Analysis Utilities is to accomplish in a quick and easy manner the entire quantitative process. The philosophy of the software is to provide conclusive statistical data with just some mouse clicks to non advanced GIS users.
I hope you have enjoyed the summer season! Back to work and here it is! A new S.A.U. s’ version (1.0.f). I’ve been correcting and tuning up some bugs in the application. The graphical interface remains still unstable and there are some major bugs that still need some fixing. However, there is a new feature regarding the Nearest Neighbour Module. Let suppose that you want to perform a Nearest Neighbour Analysis, and keep record of distance to the nearest neighbour for each point. With old versions you were able to calculate mean and histograms. But this might not fit your requirements, specially during model development. With the new 1.0.f version you can get all these numbers after processing just by exporting the points in text file format. The output file will have 12 columns. The first column is the point index or id. The second and third columns are its coordinates. The fourth, fifth, sixth are respectively the id, X coordinate and Y coordinate of the nearest neighbour. The seventh, eight and ninth are the data of the second nearest neighbour and the remainder columns are the data of the third nearest neighbour. Applying the Pythagoras’ Theorem you may get the required distance between each point ant its nearest neighbours. Good luck!
Yesterday, I discovered a bug inside the shape export routine in the new 1.0.c version.
S.A.U. was placing extra ascii extensions between the filename and the shx, shp and dbf extension. It was not supposed to do that. The problem was due to the new release of S.A.U.’s compiler software. And after a night spent on trying to remove these silly ascii stuff, here you go. . . a new version (1.0.d)!
I apologize for the inconvenience, particularly for those ESRI ArcView 3.X users, like me. Nevertheless these wrong name shape files work fine on ArcGIS 8.X and 9.X.
I didn’t had much time to check if everything works fine. If you have any kind of problem with this new version, please report it. Thank you.
S.A.U. can be conceived as a minimalist project, able to offer maximum functionality with little effort. Obviously the user has to understand the logic and the method of the spatial analyses. One of this topics has to deal with areas.
As some of you have noticed the S.A.U. main bar has a mask button. This tool (the mask button) will allow users to import a dxf polygon and use it as a boundary area in some of the analytical processes. Ok, but do we need boundaries or limits to perform point pattern analyses? In some cases the answer is, yes.
For example let’s say that you need to compute with S.A.U. the nearest neighbor R index (R=ro/re). As you know, re is based on density. Therefore an area is required.
Another method that requires boundaries is the quadrat analysis. Why? Theoretically the quadrat analysis doesn’t require any limit or area. The problem here is the procedure with which quadrats are deigned on the display window. You choose size and then you draw a rectangular area that is completely covered with the quadrats. The problem is that in most cases your point distributions wont match the rectangular shape of your quadrats mesh. And so what? Well, if you have a big rectangular area that cover your distribution, you will get a bunch of quadrats with 0. All these zeroes will mess up the real dispersion index calculable with this method. (Inside S.A.U.’s quadrat control panel you will find the tools to exclude quadrats located outside the boundary area.)
Another case is the random generator. Ok, you want an arbitrary distribution, but where? In S.A.U. instead of tricky coordinate input, you use a simple dxf to determine where the random points should be.
Nice! But there is a problem. You will be able to import only one dxf polygon at the time. In other words, the mask tool read dxf file, gets the first polygon inside the file, and then stops. For this reason I suggest to create a dxf with only one polygon. As usual, I promise I will improve algos for this issue as soon as possible!
Another problem can be that S.A.U. was trained to read standard dxf file formats. The problem is that dxf is very flexible. So there are a lot of dxf variants around. I have checked S.A.U. with common software exports. Check if your software dxf exports can be read with S.A.U. If not, send me your files to extend its capabilities.
So, you think this program might be useful for your research? Good! But there are a few things you have to know.
S.A.U. was developed with simplicity in mind. So, before you start using this program consider that at the moment there is only one file format that you can use to import your distributions inside S.A.U.: tab separated text format. Which is by the way the most simple and easy file format that came into my mind during the first stages of the design. Everybody can handle and convert distributions into tab formats. And every software package can export data in text formats that are ready tab separated file formats or that can easily be converted.
There are also some limitations. Take into account that a file with a header, lets say: ‘x’ ‘y’ or X Y Z wont work. Remove header lines on top of the file. I will add algos to handle header and meta stuff as soon as possible. Keep always in mind that the import routine is very simple with little error checking.
To start using this software you will need at least a two column file. The first for the X and the second for the Y. For some scientific purposes it may be useful to know that the largest number you may be able to import is a 64bit double precision wide number.