This is a reimplementation in Python 3.8 of the CraterstatsII software, a tool to analyse and plot crater count data for planetary surface dating.
There are various ways to install Python. If you are installing it specifically to run Craterstats, the following is suggested:
- Install Python 3.8 or higher from python.org.
- Download Craterstats and unzip the files where you choose.
- Open a command prompt/terminal window and
cdto the newly-createdcraterstats-main/ - Enter these commands to establish a Python virtual environment:
Windows:
py -m venv venv
venv\Scripts\activate.bat
py -m pip install -r requirements.txt
Linux:
python3 -m venv venv
source venv/bin/activate
python3 -m pip install -r requirements.txt
After you see the required python packages installed, the set-up is complete. In the remaining sections, you should substitute py or python3 for python according to your system.
After installation, the following commands will produce a series of example output plots and data, demonstrating the main features of the software. Plot image files are placed into the subfolder demo/, while text output – including the full command lines as they could be typed to generate the output – goes to the terminal window.
cd src
python craterstats.py -demo
Open a command prompt/terminal window and cd to craterstats-main/, then
Windows:
venv\Scripts\activate.bat
cd src
Linux:
source venv/bin/activate
cd src
The program operates through the command line to produce output in the form of publication or presentation ready graphics, or tabulated analysis results for further processing.
There are two parts to creating a Craterstats plot:
-
Specify the type of plot and any characteristics which apply to the analysis as a whole, e.g. whether differential, cumulative of other data presentation; the chronology system, displayed axis ranges
-
Specify the data to be overplotted, and which chronology model evaluations should be applied to it
In the following example, the first items define characteristics for the whole plot: -cs neukumivanov specifies chronology system 4, Mars, Neukum-Ivanov (2001) , and the -title Example plot adds the chosen title.
The -p indicates the start of an overplot definition, which should come after the part 1 settings. Following this, the path to the data source is given: this will produce a simple data plot with the default binning, colour and plot symbol. After the second -p, an additional overplot is specified: this time, a poisson age evaluation for the diameter range 0.2–0.7 km. Note that parameters within an overplot definition are separated by a ,.
python craterstats.py -cs neukumivanov -title Example plot -p source=craterstats/sample/Pickering.scc -p type=poisson,range=[.2,.7]
By default, an output file is created in the current folder with the name out.png. The output path or name can be set with the -o option. Different file types can be produced by giving the appropriate extension or with the -f option. Supported types are: png, jpg, tif, pdf, svg, txt.
Tables of chronology systems, equilibrium functions and epoch systems – which can be used with the -cs, -ef and -ep options – may be listed with the following command:
python craterstats.py -lcs
These items may specifed by their index number, e.g. -cs 4, or using any unambiguous abbreviated form, e.g. -cs ida. Similarly, -ef standard or -ef trask is equivalent to -ef 1
Numbered tables of plot symbols and colours – which can be used with the psym= and colour= options – may be listed with the following command:
python craterstats.py -lpc
and can likewise be specified by index or abbreviation, e.g. psym=1, psym=circle or psym=o all select a circle; colour=2, colour=green or colour=gr select green.
Differential plots are produced by default. To switch to a different kind, e.g. cumulative, add -pr 1 or -pr cum to the part 1 settings. Other possibilities are: 3 - relative (R), 4 - Hartmann, 5 - chronology, 6 - rate.
The complete set of options can be seen with:
python craterstats.py --help
The useable chronology systems, equilibrium functions and epoch systems are defined in the text file config/functions.txt. User functions may be added here, following the same format.
There is a text file config/default.plt which contains all the default plot settings. This may be modified to suit the choices you use most often.
To simplify the construction of the command line, certain plot properties are 'sticky'. If, for example, you specify source=craterstats/sample/Pickering.scc in the first overplot, this becomes the default for subsequent overplots. Only if you wish to introduce a different source file do you need to specify it again. This applies to other properties where it is useful, including binning=, colour= and psym=.
Explanations of concepts and calculations used in the software are given in publications below.
Arvidson, R.E., Boyce, J., Chapman, C., Cintala, M., Fulchignoni, M., Moore, H., Neukum, G., Schultz, P., Soderblom, L., Strom, R., Woronow, A., Young, R. Standard techniques for presentation and analysis of crater size–frequency data. Icarus 37, 1979.
Neukum G., Meteorite bombardment and dating of planetary surfaces (English translation, 1984). Meteoritenbombardement und Datierung planetarer Oberflächen (German original) Habilitation Thesis, Univ. of Munich, 186pp, 1983.
Michael G.G., Neukum G., Planetary surface dating from crater size-frequency distribution measurements: Partial resurfacing events and statistical age uncertainty. Earth and Planetary Science Letters 294, 2010.
Michael G.G., Planetary surface dating from crater size-frequency distribution measurements: Multiple resurfacing episodes and differential isochron fitting. Icarus 2013.
Michael G.G., Kneissl T., Neesemann A., Planetary surface dating from crater size-frequency distribution measurements: Poisson timing analysis. Icarus, 2016
Full references for specific chronology or other functions are listed with the function definitions in config/functions.txt.
A set of introductory slides from a previous workshop is available here: ftp://pdsimage2.wr.usgs.gov/pub/pigpen/tutorials/FreieUni_Workshop2012/