Arvid - Help
Arvid is a tool for displaying spatial data. It
is written in
Erik Tjong Kim Sang in the project
Maps and Grammar and makes use of
- The data can be viewed in two ways: on a map and in a table.
When you view data in a table, you can edit the data values
by replacing them and pressing Enter.
- Save File
- Data that you are viewing can be saved to your own computer.
Data saved in the map view will be saved in the format kml
(used by Google). Data saved in the table view will be saved
in the format csv (readable by Excel).
- Example maps which can be inspected and saved to your own
computer as examples of data files processed by Arvid.
- Load file
- Three file formats can be read by Arvid: csv, kml and kmz.
In the kml and kmz files positions are encoded in the
tag <coordinates> inside <Point>
inside <Placemark>. Data values are encoded
in the tag <value> inside <Data>
(with a name attribute with value value) inside
<ExtendedData> inside <Placemark>.
In the csv files, named columns latitude and
longitude express a location while the associated value
is stored in the column value. Save one of the
example maps to your own computer if you want to see an
example of the input file format used by Arvid.
- Cell size
- Maximum size of each data cell measured in map degrees. A
reasonable value is chosen by the software but you can choose
other values if you want.
- A number indicating how transparent the cell colors are.
The minimun 0 indicates complete transparency while the
maximum 1 represents no transparency. The default value is 0.2.
- Background map
- The value on here will present a background map
from OpenStreetMap. This takes extra processing time so
therefore default value is off.
- Indicates that cell values should be the average of n
(the chosen value) neighbor cells (including themselves). This
only works for numeric data values. The default value for
n is 1.
- Transition points
- Draws a transition zone of n (the chosen number)
locations. This will only work for data with exactly two
values which are non-numerical. Information for chosing the
transition cells is taken from the column numbers
which contains pairs of distances related to the data values.
- Determines a what distance (default 0) the border between
two regions lies. This will only work for data with exactly
two values which are non-numerical. This feature relies on
the values stored in the column distance.
Below the graph and the table, the number of data points (locations)
Below a graph there is a legend with the data values. You can change
the colors assigned to the data values with the drop down menus.
Clicking on a data cell will give you its name and the associated
data value. The information is displayed at the bottom left of the
Last update: 10 June 2015. erikt(at)xs4all.nl. Back to Arvid