web analytics

— urbantick

Tag "space-time Diagram"

The folks over at Oculus have been very busy developing the GeoTime software. Version 5 was released in the beginning of 2010 and they are going to released the latest update GeoTime 5.1 these days.
It includes some very interesting new features. The two major ones are the Network feature that allows the user to visualise the data as a network besides the time-space visualisation and the second major change is the support of the macOSx platform (see earlier post on mac adventours using GeoTime). This is in a sense a clear statement of independence, if there was critique that GeoTime integrates too closely with ArcGIS. However of course it continues to integrate well with Arc and support for the new ArcGIS 10 comes with the new GeoTime update.

The software is perfectly fitted for the UrbanDiary project that works with GPS tracks of individuals, investigating the spatial extension of everyday routines in the city. It is basically a purely spatial-temporal dataset. In a few easy steps it is possible to see the data visualised in a simultaneously temporal and spatial way, animate it as well as start analysing it.

Image by urbanTick / A view of different GPS tracks over the period of one month, using GeoTime and an OSM base map pulled in via ArcGIS.

The move away from a secondary software import via ArcGIS or Excel was a good move that came with version 5.0. The importing formats have been extended and redesigned with the release of version 5.0 to include CSV, XLS, and SHP file formats as well as the in version 4.0 existing KML. It is now handled directly by GeoTime through a functional assistant. With version 5.1 the import of GPX file format is added. Data from the GPS exported in this format can be loaded and added to a project directly.
The new dialogue allows to filter the data at import. This is useful especially for my crappy overloaded tables in which I tried to record way to much. The selection of just the five essential columns makes for a much more slik workflow.
GeoTIme focuses on temporal data, however the integration with realtime data has only be introduced recently with the 5.0 release. Now users can import live feeds via Geo RSS that automatically updates.

The data is initially visualised in the 3d view as a time-space cube. To interact with time one finds the tools on the left hand side vertically arranged. On the right hand side the menu provides a range of other tools including representation settings, pattern analysis, reporting tools and the new network tool.

Image by Oculus / An example using the new network tool in GeoTime visualising a computer network.

The network tool is a whole new field that has been added to GeoTime with this functionality. This is particularly interesting for the analysis of complex structure that include spatial and non spatial data, such as for example phone call data or financial transaction. In the context of the UrbanDiary project for which GeoTime is used here this new tool becomes interesting for the investigation of combinatory data from GPS and mental maps, as for the analysis of interrelationships between landmarks and actual route. For the visualisation different present network settings are available. Furthermore it integrates with the 3D visualisation of the spatial data and the network graph is directly linked to the time-space cube and highlighted areas correspond across the two visualisations. So specific sections identified for further investigation at one end can be look at from a different perspective at the other end.

For the data analysis in the spatial-temporal section, one of the new features in this 5.1 release is the stationary detector. The data can now be queried for events that have not moved in space over a longer period of time. This is useful for the data verification as well as detection of move and rest patterns.

One of the remaining points of critique is still the graphical representation of the visualisation as well as the range, simplicity and of possible manipulations of it. There have been however, some changes made and for example the colour palette has been extended. But still both the interface and the results are still very technical thought of and rendered. It would not ne a mater of just making it all fancy and colourful with rounded corners, but it would need one strong design direction as a well as an overall visual simplification.

Image by urbanTick / Applying the stationary finder to a track imported via GPX directly into GeoTime. This highlights the areas where the GPS device has not moved more than 100 metres over a period of more than 8 hours. It uses the OSM base map pulled in via the ArcGIS link.

In an comment on GeoTime 4.0, I hade described it as an end-of-the-line analysis tool. This was because the data could not be directly exported to other software packages. This has changed with this most recent update, now CSV export is supported in addition to the KML and screenshot export. The analysed file can be passed on to other software or users which dramatically enhances the usage and the integration of GeoTime.

Image by Oculus / The GeoTime 5.1 Logo.

In this sense the spaceTime aquarium has become a lot more sophisticated with this GeoTime 5.1 release. At the same time, though, it ha become accessibel for a much broader range of specialised fields through the extended palette of tools. It can now integrate in a workflow, be run as stand alone analysis software as well as operate across platforms. GeoTime is a very specialised tool and definitely offers the quickest and most comprehensive set of visualisation and analysis tools for temporal data.

For demos and further information on the GeoTime project use the inks or go HERE or HERE for earlier posts about GeoTime on urbanTick.

Read More

The Oxford Dictionary defines time as ‘the indefinite continued progress of existence and events in the past, present, and future regarded as a whole’. With this the definition leaves open a lot of the really interesting questions, or does it include additional possibilities?
It does name a number of features such as past, present and future, as some sort of categories. Further it list progress implying change or even improvement. This is attributed two further elements continued and indefinite. The first one hinting at ongoing change and the later one ads a never ending property which is sort of in itself an timely attribute.
However to come to the questions, interesting are the aspects of linearity, the arrow of time, the multitude, singular or plural and of course the conception.
In todays everyday life, time has become so immersed and integrated it is generally regarded as something a natural as breathing (Glennie & Thrift, 2009, Shaping the Day). Usually perceived as an additional sense, a timesense?, but at least a natural fact. However, this is fiercely debated and often opposed by scholars. Nowadays aspects of time are everywhere everything is on time, timepieces rule every single step we take in the city and we surround us with timepieces (to make the clear distinction between clocks, watches and timepieces) where ever we are. Most household kitchens will nowadays spot about five different fix installed units telling the time of day, plus some gadgets telling the time temporal or are mobile. Of course there is more, navigation, communication, computers all really on hyper accurate timepieces, without which nothing would work.
This sort of clocktime (Glennie & Thrift, 2009, Shaping the Day) is however, not very old.
Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of that radiation which corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom. This has developed from the discovery by Galileo that a pendulum swings regularly regardless of the distance it covers. There were however timepieces long before this, sundials and water clocks, but they were less reliable and uniformed.
Since Galileo’s discover around 1600 the concept of the clock developed and gained increasing significance in everyday life particularly in social life, as an regulator of practices. This nowadays manifests in the time disciplinary enforcing institutions such as schools or workplaces, but also leisure activities and entertainment.

The Creation of Adam, ca 1511
Image taken from Wikipedia / The Creation of Adam, ca 1511, by Michelangelo Buonarroti (1475–1564)

In terms of rituals and religious practices time has played an important role for a much longer time. This has obviously defined the cultural conception of time. The linear understanding of time can be traced in Christianity with the ideas of the Beginning, God’s creation of Adam and Eve and the End as the Second Coming of Christ or the last Judgement. A one way, linear procession dominates the scenes and leaves a lasting impression in the collective memory.

The Last Judgement. The Louvre.
Image taken from Wikipedia / The Last Judgement. The Louvre. Date not known, but the work was engraved in 1615. It was probably painted in the last decades of the Valois dynasty (1560–89), by Jean Cousin the Younger, also called Jehan Cousin Le Jeune (lived c. 1522–1595).

In other cultures and religions however the conception of time is different. Cyclical in Budhism and for example in the Egyptian culture. The Greeks used two concepts for time, a formal objective Chronos and a expressive subjective time, Kairos, as an opportunity as gap or timeout.
In the culture of the Hopi Indians, natives in the south west of the Americas, the concept of time does not cover the same three tenses present, past and future. Instead the Hopi’s use only two times (Whorf), an objective time and a subjective time (the terms might be confusing but the anthropology research reaches back in time where these terms might have had slightly different coinings). Those are manifested (object) and manifesting (subject). Objective elements are all the things accessible to the sense, being physical. What we call future would be in the real of the subject, the desire or the mental. The Hopi culture also relates time to space in the sense that distance is part of the manifested as a duration. As a result simultaneity does not exist. something far away can not have the same time since the ‘distance’ lies in between. (Tuan 1977, p.120) Spatially very interesting here is how the two concepts meet in the distance, far away merges with the dream.

Image taken from Space and Place by Yi-Fe Tuan 1977 / Page 121, Figure 15. Hopi space time: subjective and objective realms. The objective realm is the horizontal space within the cardinal grid, but at the distant edges it merges with the subjective realm as represented by the vertical axis.

Science has occupied the debate and dominated the conception of times as linear for the best part since Galileo’s pendulum. Only in the 20st century, the discussions on the topic, covered in various disciplines has taken on a different perspective. Where Newton strongly argued for an objective time, a single and true time concept, Einstein developed with the relativity theory an alternative concept, allocating time a subjective role, with time passing at different speeds for different observers. This is the development in physics, but simultaneously the conception of time was reexamined by philosophers, especially the french league with Bourdieux, Lefebvre (Rhythmanalysis), Serra, DeCerteaux and others. Here the debate between objective and subjective time continued with the phenomenologists entering the debate. However, as Elias points out in his Time: an Essay, both view in their base found on the concept that time is something given, a fixe instance, measurable. In this context the third concept of social time was developed. As Elias describes it (Elias 1992): ‘To perceive time requires focusing-units (humans) capable of forming a mental picture in which event A, B and C follow one after another, are present together and yet, at the same time, are seen clearly as not having happened together; is a synthesis only humans are capable of and learned and developed over generations. Knowledge of time’.
In the current debate most philosophers would agree with a concept of time that is non linear and the concept of multiple times is accepted as a social aspect.

In exact science however, the linear singular clocktime continues to dominate everything. The discussions as well as the projects and work undertaken. This lead to the increasing exclusion of temporal aspect due to the arising problems with the integration of linear time that doesn’t fit with the complex systemic concepts any longer.

This could be about to change with the recent envelopment in spatial research and the focus on mobility and location data. Aspects of temporality all of a sudden move into the prime light. This of course goes hand in hand with a shift in development and availability of specialised and capable technology.

There have, in visualisation terms, interesting approaches developed. The time geography dominated by Thorsten Hagerstrand is one example (actually this one goes beyond a mere visualisation), but also the time distance based distortion maps or animated visuals. Also the aspect of comparison between two instances is used quite often. Usually the same object is shown at two different stages to visualise the change that took place between the two points in time. Implying the Newtonian time aspects apply.

How aspects of the modern discussion on the term time apply to science in the field of geography and particularly spacial analysis is still blurred, even though we increasingly see promising approaches emerge.

The Last Judgement. The Louvre.
Image taken from datavisualisation.ch / Ebb & Flow of Book Characters by Jeff Clark working with adapted StreamGraph code to work with arbitrary text documents.

Read More

Together with the tweet-O-meter project run at CASA as part of the NeISS research project we have collected location tagged tweets around London (M25). As described in an earlier post on this HERE, the idea is to capture the urban narrative. The current data covers a whole weekend from Friday evening to Monday morning and the set holds some 380’000 individual tweets. However this brakes down to 60’000 truly geo referenced tweets, by 5’500 individual users. The thing is, that these are only the mobile tweets and they are captured only if the locations sharing is activated in the twitter profile. Still this makes an average of 10.6 tweets per mobile user over the weekend. Overall we have 39’222 individual users witch makes some 9.7 tweets. So the mobile users seem to message slightly more, but not significantly as one could maybe expect.
In terms of density per location as one could expect the focus is in the centre. There are local hotspots as the weekend progresses, such as Kings Cross and Old Street. But then there seems to be a accumulation of density along the transport lines into and out of the centre.
To visualise the temporality of the data tweets are in the below clip output as a message cloud rising and hovering above London. It is a simple time-space aquarium were the time is plotted as the hight information. The later in the weekend the tweet is sent the higher above the city it floats. As the density develops the low times can be clearly spotted, when it thins out the lines and London sleeps. The animation is rendered in Google Earth, with the KML file brought in through a VB script from Excel. Once set up this is quite a flexible combination. However, the KML file can get quite big, since there is a lot of information contained with all the messages.

Read More


Image taken from richardlong.org – One Hour, a six minute circle walk on Dartmoor 1984

Currently there is a large Richard Long exhibition on at the Tate Britain in London with the “Heaven and Earth“ exhibition until 06 of September 2009. It is the first large exhibition of the British artist in eighteen years. The exhibition features sculptures, large scale mud wall works and old and new photographic and text works. Also important to mention is the addition room with a large collection of his books, where some real jewels of publication can be seen.
Why featuring a landscape artist on the blog in the context of rhythms and movement? There are several reasons ranging from aspects of time, use of space and movement to aspects of mapping and visualization. On the Tate Britain website the work is introduced and traced back to Long’s love of nature and environmental experience.
A lot of his works are temporal, maybe most of them. While working with the landscape obviously the method of documenting the work becomes central. Especially in Long’s work as a lot of his landscape works derive from the interaction of body and landscape or the reaction of the artist to the landscape. The methods he uses to document this interaction range from taking a picture of his interventions to mapping his activities. His installations of large scale stone circles and mud wall drawings can also be seen in the context of documenting. Long brings elements of the nature into the exhibition spaces being totally aware of the transformation related to context.
The aspect of time plays a major role in all works but is particularly present in the photographs that document works he as produced/performed in remote places, like for example ”a line made by walking“.
Long appears in most of his works as the actor and a driven personality. It seems like he just can’t stop doing this. Particularly in his works of walks he is restless and eager to move. Also here the time plays a major role as a defining element, maybe even a tool to stop Long from simply keep on walking. Works such as “One Hour – a sixty minute walk on Darthmoor“ or “A five day walk”.
The mapping of his walks covers a number of additional topics including the aspect of space and space limitation. The geometry of the circle is Longs main element and features in his sculptures, installations, but also his walks as confining or excluding boundaries. In a sense some of his maps can be read as a different type of space-time diagrams.

Image taken from richardlong.org – A Line Made by Walking, England 1967

Read More

The problem of how to visualize time has been and is still challenging. There is a number of approaches out there, but the one general applicable approach has not been found yet.
So far a number of different approaches have been used and tested in this research work.
The first one was plain tracking paths. The time is actually inherent these images as the path is a sequence of points and these points where recorded in time one after the other. Also different lines are distinct in time as one tracked individual can only produce one path at the time. Theoretically this explanations work very well, but in practice when it comes to analyze these drawings all one can see is dens areas, hotspots and trends. THe aspect of time gets completely lost, specifically when one tries to look at one path relative to an other. They all seem to have the same time.

Image by urbanTick – Plymouth365, one year worth of tracks

The second approach was playing the track record as a movie. With this technique it became possible to repay the recorded sequence and with the help of the movie simulate the passage of time. The recorded sequence of points is replayed according to the time stamps saved with each point. For analyzing purposes the tracks are replayed simultaneously at the same time. In this way the tracks can be followed relative to all the others. WIth this technique it is possible to distinguish between moving and static records. In the first example the path only show the location and time for activity on the move, e.g. going from A to B, but A and B are not included as a time period. This lies in the nature of the map that is solely spatial. Whereas in the movie the duration of A or B is displayed with a static dot that stays at this specific location of A or B for the relative time. The difficulty with the replay movies is the speed of replay. If it is too slow it is boring and takes forever. Also the is a limitation to how much is manageable to oversee of a time period. If it gets too long it is not possible to directly link the activities in the beginning of the sequence and the end of the sequence. Nevertheless this approach has been very popular with a wider community. The clips replaying the Plymouth365 track records have been watched over 5500 time in past two month. So it seems to be an approach that is easier accessible or consumable.

plymouth365_24h_sun from urbanTick on Vimeo.
Plymouth365_dayAndNight, to give a stronger sense of time the effect of day and night have been introduced

The third approach in visualizing time was the introduction of the third dimension. This dimension was not used to display the hight, but time. There is originally already hight information in the GPS record, but this has been replaced by the time information. This created 3d matrix with lat and long as x and y, but then time as z (hight). This visualization has been developed by Torsten Haegerstrand and the Lund School in the 1970ties. It was called the Space-Time Aquarium. This is probably at the same time the first time researchers in geography developed ideas for this topic of movement analysis. This technique produces very nice 3d shapes and are visually very pretty. For analysis purposes they tend to become very quickly much too complicated. For a limited number of tracks it can be useful and meaning full, but for a large number, such as the Plymouth365 full record, it is in the current way of the 3d model not very useful. Although the main features do show up. The “home“ location as the major spine, ”work“ locations as a secondary spine and the ”wall” for busy connection lines do pop out. Also there are nice smaller elements such as the “steps” for activities with stop and motion or the “spiral” for activities that took place over a longer period of time in more or less the same location, e.g. playground, lunch brake. A major problem is the connection between the model and the surface that provides the sense of location. The more time passes the more this connection get lost and later in the afternoon or in the evenings it often is completely lost. An other problem at the moment is the presentation of these models. They just don’t look good on images as one naturally ants to rotate them.

Image by urbanTick – Plymouth365, Space-Time Aquarium

The fourth and latest approach is the visualization of time on a map using colours to give time information. Each path segment here is coloured according to time. It starts in the morning with bright red changes to yellow and green over noon, the afternoon is blue and the evening changes again to purple. This actually give a pretty good sense of time wile reading the map and also enables the reading of the tracks relative to one another. The main problem is probably that it is static. Once generated it is a drawing and bears not much of a time representation as a dynamic element. Very much like the first approach it capture and frames a point in time.

Read More

I have been working with the data material Plymouth365.
Different approaches have now been tested and it looks promising that this could lead to something.
I have been focusing on the analysis of the data in the context of a 24h day. Basically what I did is squeezed in all the days into one sample day and plot it. In other words, all the days are superimposed onto one day.

Image by urbanTick – activity graph

(These are screenshot movies and shows Google Earth playing the tracks over 24hours. It is a first shot at it, so needs some cleaning and tweaking.)

Image by urbanTick – aquarium, Time space diagram referred to as the aquarium. After Kwan (2004)

This data is actually pretty new, these are the new London tracks from October and November in 2008)

Read More