The data format in VizAssist uses the following definitions and principles:
the file format is the international CSV format, with comma ”,” as separator and ”.” in numbers
the actual version of VizAssist assumes that your file will be in the proper “VizAssist” format (see below)
several demo files are provided with various characteristics, so please have a look at them to get a better idea of the file format: multidimensional data (Iris, Wine, Pima, French Taxes) with images or url (Box office mojo), times series (French demography, Population), graphs (VizAssist project).
The VizAsssist file format is as follows:
Line 1: the name of each data attribute (i.e., the header of each column). These will appear for instance in the legend of the generated visualizations,
Line 2: the type of each data attribute (actual types: numeric, ordinal, nominal, time, imageurl, url, source, target, country),
Line 3: the importance of each attribute (in [0,100]). Those values are used to tell VizAssist about your preferences for some attributes over the others. If you have no preferences, then please set this line to 50,…,50
Line 4: the number of different values for each attribute
Line 5 and others: the data items. One value is required for each column. Missing values are not handled by VizAssist.
Here is an example, with the Iris dataset:
Petal width,Petal length,Sepal length,Sepal width,Class
numeric,numeric,numeric,numeric,nominal
50,50,50,50,50
150,150,150,150,3
5.1,3.5,1.4,0.2,Iris-setosa
4.9,3.0,1.4,0.2,Iris-setosa
4.7,3.2,1.3,0.2,Iris-setosa
…
Another example with time series:
Month,Population size,Nb of weddings,Weddings rate (nb of w. for 1000 people),Nb of birth (alive),Birth rate (nb of b. for 1000 people),Nb of death ,Death rate (nb of death for 1000 people),Nb of children death (less than 1 year),Children death rate (nb of c. d. for 1000 birth)
time,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric
50,50,50,50,50,50,50,50,50,50
456,456,456,456,456,456,456,456,456,456
1975-01-01,52600,15188,3.4,62600,14,55805,12.5,998,15.9
1975-02-01,52608,18847,4.7,58062,14.4,44628,11.1,831,14.3
1975-03-01,52623,30838,6.9,65881,14.7,49246,11,959,14.6
1975-04-01,52640,36151,8.4,68355,15.8,47957,11.1,886,13
…
More details about the data attributes types:
numeric: a dot is use to separate the integer part from the fraction part
ordinal: symbolic values that are ordered, like “small”, “medium”, “large”. VizAssist uses the alphabetical order, so you should rename those values as “a-small”, “b-medium”, “c-large”, to be sure that they will be processed in the right order,
nominal: symbolic values that are unordered
time: a ordered time stamp attribute. This attribute is used to define the time axis in time series,
imageurl: a url to an external image that can be included in the visualizations,
url: same idea but for any kind of url,
country: a code for the name of a country (geographical location that will be used in a world map visualization → not implemented yet, sorry!)
source, target: are used to specify a graph in your CSV file. “Source” and “Target” are nodes labels between which you want to create an edge.
nodenumeric, nodenominal, edgenumeric, edgenominal: these are data attributes that correspond, respectively, to properties of nodes and edges. These will only be mapped, respectively, to visual properties of nodes or edges only.
Even more details about the representation of graphs (see the demo files):
The use a of single CSV file to represent a graph (i.e., nodes and edges) has consequences on the VizAssist format for graphs.
To represent a graph, you need one “source” and one “target” attribute.
When the value of “source” is different from the value of “target”, then VizAssist interprets this as an edge (example: “Node0” in the source column and “Node1” in the target column means that an edge “Node0→Node1” will be created).
When the value of “source” is equal to the value of “target”, then VizAssist interprets this a node (example: “Node0” in the source column and “Node0” in the target column). All nodes should be represented.
The CSV file for a graph contains two contiguous parts: one is about the edges, and the other is about the nodes.
Columns of type “nodenumeric” or “nodenominal” denote the properties of the nodes.
Columns of type “edgenumeric” or “edgenominal” denote the properties of the edges.
About the dataset size:
the visualizations in D3 and in a web interface can handle only a limited number of data items,
the loaded dataset should not exceed a few thousands lines (but several hundred of columns seem to be possible)