Understanding the ClustrMaps 'timeline': updates and archives

[See definitions below.] Note that for users of the free ClustrMaps service, only the thumbnail maps, i.e. NOT the large maps, are saved in the archive! You may want to save your own copy of the large map image occasionally to display to your readers or to keep for yourself. For ClustrMaps+ users, all the large maps are saved too.

When reading map totals, it may help you to understand the relationship between 'map updates' and 'map archives'. In the timeline below, an imaginary timeline extends from left to right, with the 3 large red bars representing 'archive moments' (including the original 'Start' at the very left). The tiny vertical 'stripes' (37 of them in all from left to right) each depect the instant that a web user has actually visited the site we are examining (you can think of this as 37 mouse clicks that have taken visitors to the site in question). The small triangles labelled 'a' to 'i' represent 9 moments when the maps are actually updated ('rendered' in graphical form for users to look at). Finally, the 4 downward facing green arrows labelled 'Look 1' to 'Look 4' represent 4 instants in time when we have decided to actually inspect the ClustrMaps display and look at the totals.

The very first time we decide to inspect the map ('Look 1'), 6 visits have been 'logged' in the database. But because the most recent actual 'map update' (image rendering) has occurred at the triangle labelled 'a', this is what we actually see displayed on the map: Look 1: 4 visits since Start, total visits 4 since Start

For the second time we decide to inspect the map ('Look 2'), we happen to coincide with the update labelled 'c', and this is what we would see: Look 2: 12 visits since Start, total visits 12 since Start

The map is given a 'clean slate' (dots cleared) at every archive, but the grand totals are still stored in the database. When we inspect the map again a third and fourth time ('Look 3' and 'Look 4'), this is what we see:

Look 3: 3 visits since Archive 1, total visits 20 since Start

(notice that the one single visit between update 'e' and Look 3 does not appear in the map, although it is logged in the running totals for later)

Look 4: 12 visits since Archive 1, total visits 29 since Start

Effects of Changing Update and Archive Frequency

When you log in to your account under the Admin link, you are offered the option of changing the update and archive frequencies (within limits, as defaults are selected for you automatically). The figures below take the same timeline as that presented above (37 visits shown in total from left to right), and show the effect of changing the update and archive frequencies. First, let's suppose we double the time between updates, as shown below, and examine the totals we would see if we looked at the maps at the same moments we looked earlier ('Look 1' to 'Look 4').

Look 1: 0 visits since Start, total visits 0 since Start (because no map updates, or renderings, have yet occurred!)

Look 2: 7 visits since Start, total visits 7 since Start (because update 'a' was the most recent)

Look 3: 0 visits since Archive 1, total visits 17 since Start (because no updates have occured in this new archive period)

Look 4: 7 visits since Archive 1, total visits 24 since Start (because update 'c' was the most recent)

There are pros and cons to changing the update frequency: slowing it down as in this example has the disadvantage of being 'less timely', i.e. you have to wait longer for the latest totals to show up, but the advantage of ensuring that each map update is more 'noticeable' (the new dots that appear will generally be more distinguishable the longer you wait to update the maps), and it also puts less stress on the server.

Consider now what happens if we take the original timeline diagram at the top of this page, and we leave the update frequency the same but we archive more often.

Once again, let's look at the maps at the same moments we looked earlier ('Look 1' to 'Look 4').

Look 1: 4 visits since Start, total visits 4 since Start (because map update 'a' was the most recent)

Look 2: 5 visits since Archive 1, total visits 12 since Start (because update 'c' was the most recent)

Look 3: 3 visits since Archive 2, total visits 20 since Start (because update 'e' was the most recent)

Look 4: 5 visits since Archive 3, total visits 29 since Start (because update 'g' was the most recent)

There are pros and cons to changing the archive frequency: archiving more often as in this example has the disadvantage of providing 'sparser maps', so you have to look back amongst the archives to see the distribution of earlier visitors, but the advantage of ensuring that current maps are easier to study (the new dots that appear will generally be more distinguishable the more often you archive old maps), which is especially useful for extremely busy sites.

Adjusting your own update and archive frequencies

When you log in to your account under the Admin link, you are offered the option of changing the update and archive frequencies. Here are the key definitions to keep in mind, along with a table showing the limit on displayed visits for each combination:

Map archive moves the current maps into the archive and a new current map starts counting from zero. The cumulative totals continue to grow. The intuitive reason for changing your archive frequency is this: if you are bored with all those dots filling up your map and only want to see the 'fresh' ones, then archive more often! Note that for users of the free ClustrMaps service, only the thumbnail maps, i.e. NOT the large maps, are saved in the archive! You may want to save your own copy of the large map image occasionally to display to your readers or to keep for yourself. For ClustrMaps+ users, all the large maps are saved too.

Map update re-generates (re-renders) the current map. Note that the generation is not done in case the number of visits since the last map was generated is smaller than a fixed percent of the visits logged in that time (i.e. an increase of X% is a prerequisite for fresh updates). Because the value of 'X' may change with peak demand, we keep its value specified in one specific place on our FAQ item about map update frequency. (Also check our News site for any late-breaking information).

Number of displayed visits is the number of visits which are displayed in the current map; or more precisely the number of visits since the map was archived the last time.

The table below shows the allowed number of displayed visits for different combinations of updates and archive frequency (when you exceed those limits you will receive a polite email and be 'nudged' downwards into the next cell, i.e. updated less often):

Bear in mind that there are two different values checked for ClustrMaps users: (a) the daily number of visits that your site has received, and (b) number of visits actually shown in the current map. While (a) is simply the normal limit for each category of users (see the products page for the actual limits), there are several limits for (b) depending on frequency of map updates (because number of visits shown affects time needed for the map update).

Limits for (b) are higher for less frequent map updates (10k for daily, 50k for weekly, 200k for monthly). If you go over the limit and still want more frequent updates (e.g. you may want to stick with daily updates), you can go to the Admin page and increase frequency of archives (which is by default once a year) to monthly or even weekly. Then the number of shown visits will be less likely to reach the limit for daily updates. After you increase the archive frequency you'll be able to set the map updates back to be done more often.

The limit (b) is there to protect server from spending too much time updating the maps; especially as the complexity grows polynomially with number of vitits. AND also because there is not a big visual difference between having 20k and 200k visits diplayed in the map - the distribution of dots does not change significantly.