Data Logging and Software for Weather Stations

Davis Logger & Software Topics

Handling weather data on PCs & websites is covered extensively on this site - here are some links  to related PC and website topics (current page is shown unlinked):

Please note: This particular web page may take a few moments to load because it contains a number of large image examples, some of which are showing live data. To avoid loading the contributing servers unnecessarily, please don't leave this page open in your browser for very extended periods.

And an upfront apology: This is rather a long web page because we wanted to show a  whole range of different PC and web page displays in one place.  There's also quite a bit of information here in total but just skip over the text and browse the images if you wish - the text will all still be here if you wish to return for a closer read.

To introduce the various data logging and software products that we offer, we need to set the scene with some examples of the many ways in which weather data can be displayed automatically using data feeds from our weather stations. This page first summarises what's possible with a modern data logger, briefly describes the logger hardware and then shows quite a number of illustrations of the diverse data presentations that can be easily generated on local PC displays and on websites.

One of the major benefits now available with lower-cost, automatic weather stations such as the Davis systems is that all the weather data generated can be processed automatically by PC and, if you wish, included in visually impressive data presentations, both locally to the weather station, at long distance and on websites as in the example above. The range of capabilities includes:

  • Automatic long-term logging of detailed weather records, allowing high-resolution archives of weather data to accumulate over months and years;
  • Customisable (depending on software used) real-time displays of current weather conditions on PC (or Mac) monitors and large screens;
  • Analysis of logged data (eg to generate monthly summary reports) and graphical presentation of data on time-scales ranging from hours to months in visually impressive charts;
  • Any of the above three capabilities may be implemented using long distance data links and/or on websites;
  • Sending alarm messages (eg by email or SMS) and control of external electrical equipment such as heating and ventilating systems in response to changing weather conditions;

These include impressive presentations of weather data on web pages such as the live example below (from our workshop at Ely in East Anglia (UK); this display should update automatically every 5 minutes), which is easily created without specialist knowledge and at relatively low cost. This particular example uses the Davis 6555 WeatherlinkIP data logger uploading automatically to the central processing site at weatherlink.com. Most users will very readily be able to recreate this sort of data presentation on their own websites, but read on below for illustrations of many other options.

In fact, so many diverse applications and data presentations are feasible nowadays, generally at low cost, that in the limited space here we can do no more than give a flavour of the possibilities, illustrated with some examples. Many of these features and options are available more or less 'out of the box'; for other, more specialist projects, especially for more sophisticated web page designs, some straightforward development work may be needed. But if you can't see exactly what you're looking for in the examples here, then please get in touch and we'll do our best to advise.

It's perhaps worth adding that not all applications need sophisticated logging solutions - sometimes the requirement is just for the simplest, lowest-cost way of automatically logging a long-term record of basic weather readings such as wind conditions at an unattended site. Although most of the descriptions below exemplify reasonably high-tech logging and data handling solutions, we do also have loggers for the simpler applications such as the LeWL logger.

To make some sense of what the examples here show, some brief explanation of the different types of available data feeds, loggers and software may be helpful.

The Data Logger

Console with logger installedWeatherlink USB Data LoggerData loggers come in different shapes and sizes according to their maker and role. For the Davis stations, for example, the logger is typically a relatively small module that fits into a recess on the lower rear of the display console unit. (See close-up logger image left and installed into a console right.) Once installed, the logger effectively becomes part of the console. Some other standalone loggers such as the LeWL wind logger look quite different (see LeWL page).

Data loggers for the weather stations we sell can perform two distinct roles in generating archive data and real-time data. It's worth appreciating the difference between these two roles because it makes understanding how best to use the loggers in different applications much clearer (but don't worry if this explanation isn't crystal-clear at first sight - most logging configurations are relatively easy to set up and don't necessarily require behind-the-scenes knowledge; just browse through the various examples here to see what's possible):

  • Archive data logging (also termed true data logging): In this role the logger receives data either direct from the weather sensors or - more commonly - after initial processing of the raw weather data by the display console and then automatically stores summary values for the various weather sensor readings at preset intervals, for example every minute or 10 minutes or every hour. In this way, the data logger can accumulate a complete and detailed history of weather conditions over a period - potentially up to a week or a month or even more, depending on the type and capacity of the logger. This archive of summarised data remains stored in the data logger until it is connected to a PC and a PC program requests a download of the archive (which may be just a partial download, ie of any new data that has not previously been downloaded).
  • Real-time data feeds: The logger provides an interface to a PC which allows real-time data (ie readings refreshed every few seconds) to be accessed by programs running on the linked PC. It's this type of data feed that will be used to provide real-time weather displays on PC monitors, websites etc. Typically, this real-time data is transient and not stored at all by the logger - ie if a linked PC is not listening in when the latest data refresh is available then that data record will be lost.

All Davis loggers are clever enough to be able to perform both of these roles simultaneously, if required to do so. But some of the simpler loggers, such as the LeWL logger, are only usually required to carry out the archive data role.

There can be a further twist to these archive/real-time roles. Some logging systems using third-party software programs are set up with a PC constantly switched on and listening to the real-time data. In these systems, it's the PC program and not the logger that processes the real-time data stream and summarises it to generate the archive data. Not surprisingly, the format in which the archive data is stored on the PC's hard drive will depend on the processing program being used.

In addition to the above capabilities, there are also a set of advanced Davis data loggers, which offer important further features in addition to the two archive and real-time data roles - further details available on the Advanced logger pages.

Also, for anyone to whom this might be of interest, we are able to source a Modbus interface to the standard Davis 6510SER serial logger - please see the page on Modbus Accessories for further details.

Software For Use With Davis Loggers

Overview

Data from the logger obviously has to be fed to a software program for processing as required, whether that be a real-time weather conditions display, a summary of the data over a period of time in text or chart form, or in managing a remote automatically-updating website. The data feeds from a logger are typically in special data formats and so it's important that the software can decode the data as required - for this reason compatibility with the particular type of logger is needed. (NB With one or two exceptions, the data loggers cannot output in either plain text format or in complete web pages - a computer is generally needed to create the final display at some point between the logger and the display. Typically this will be a local PC linked directly to the logger, but there are ways of feeding data to a remote server direct from the logger when the presence of the intermediate computer won't be very apparent to the end-user.) Davis loggers are widely used and so are compatible with many weather programs but in general it's worth checking that that any program that you plan to use is compatible with your specific type of logger - the PC interface type eg USB vs IP may be important as well as make/model - and vice versa.

Weatherlink packThe best-known program available for use with the Davis stations and loggers is Davis's own Weatherlink program, which is supplied  as a standard part of the Weatherlink pack and so every logger purchaser also gets a 'free' copy of the Davis software - it is not necessary to specify the software separately, unless you wish to use a non-standard program. ('Weatherlink', perhaps a little confusingly, is the name used by Davis for the logger itself, their own processing program and also the standard pack containing both of these items.) A separate description of the Weatherlink pack is available on its own page.

So many Davis VP-family stations have been sold worldwide since 2001 that an active market has developed in third-party programs that are compatible with the Davis loggers, with the result that there's a wide choice of programs, including Weatherlink itself of course. We're often asked about which program is the best to use, but this isn't an easy question to answer - each of the alternative programs to Weatherlink has its own features and pros and cons (summarised on our compatible software page and illustrated in some of the examples below) - and so it really depends on your own requirements and priorities. We generally recommend looking at the Weatherlink program itself to start with - you get a copy with any Davis logger and it's perhaps the most professionally produced and most widely used of all the programs. But it's not as fully-featured as say Weather Display, nor is its real-time display as attractive as Weather Display Live. There's also a relative newcomer called Cumulus that's currently free to use and is attracting a lot of new users because of its balance of feature-set, ease-of-use and clarity.

Most Davis station owners run Windows on their PCs and so inevitably the great bulk of the Weatherlink and third-party program development has focused on Windows software versions. However, both the Weatherlink program and certain other programs are available in a Mac version. Linux versions of a few third-party programs are also starting to appear. It should be said that although these non-Windows versions typically work well enough, they are often relatively limited in terms of features. If at all possible we recommend using the Windows versions - not for any theological reason, eg in the Mac vs Windows debate, but simply for the reality that they will be more fully-featured and more thoroughly developed by virtue of their much wider appeal and use.

With this background, the following section shows a number of examples of compatible software and illustrates both the range of data presentations available and the specific presentations generated by different programs. Please remember that there's only space here for a few representative examples - a more comprehensive review could fill almost a whole website. And we're also limiting this section to what's possible with the standard loggers, since, for example, the Davis advanced Streaming loggers offer still further possibilities.

Software Features & Examples

We've divided these examples into two groups: those as viewed locally on the PC linked directly to the weather station, and those that are designed to be used on a website. (NB Networked PCs not linking directly to the logger tend to use similar data presentations to websites.)

These two types of presentation often end up looking very different because different software technologies need to be used to display data on a web page compared to those commonly used on local PC displays. Sometimes, completely separate programs written by different designers are used to generate the website displays and so personal designer preferences can also account for major differences in the look of a given presentation. Finally, website displays may be constrained by the amount of data that can be uploaded to the website and by how often it's practicable to run an upload. That said, there are ways of updating even website displays essentially in real time but these need special add-on software programs, as detailed below. So, in practice, local and website displays can look very different.

Local PC Data Presentations

Please note: The images below are reduced in size somewhat from the originals - please click on an image to see it in greater detail and in a new window (but note that even this larger image will still not necessarily be the full-sized image visible on a high resolution monitor and so will not reflect the full detail and clarity of the real thing).

There are many ways of viewing the weather data with a local PC - for example the display may be text-only or graphic and may relate to the latest real-time data or to summary data over a period such as a calendar month.

  • Weatherlink Bulletin ScreenReal-time display (graphical) - This is an example of the Weatherlink 'Bulletin' screen. This screen updates every 2 seconds or so and at each update the wind direction (top left) and wind speed (top right) dials will flick to show the latest wind readings. (NB The exact format of this screen will vary according to the sensors fitted, eg this example shows displays from the optional solar and UV sensors - bottom left and right.)

 

  • Weatherlink Summary ScreenReal-time display (text) - This is an example of the Weatherlink Summary screen, which updates in real time and shows current readings for all main weather parameters, including - where relevant - high and low values for today so far. Some additional information such as mean wind speeds over four different intervals plus forecast and calendar data is also shown. As with all Weatherlink screens, the exact screen format will depend on the sensors types installed.

 

  • Combination Real-time and Historic Data presentation. (No larger image available) This is an interesting data presentation from the Cumulus software that combines three features:
    • Cumuls real-time screenText display of current conditions;
    • Text display of historic conditions;
    • Graphical presentation of wind data;.

 

  • WLR Sample Report - ReducedMonthly summary (text) - An image of a PDF document produced by the add-on program Weatherlink Reporter that shows summary day-by-day data for a user- selected set of weather parameters over one complete calendar month.

 

  • Cumulus Monthly Chart ImageSummary chart (graphical) I - Cumulus (No larger image available) . These summary charts provide a visual method of reviewing weather conditions over a period such as a week or month. Depending on the specific program in use, it's usually easy to switch between different weather parameters and time periods with a couple of mouse clicks.

 

  • Weatherlink Monthly Chart ImageSummary chart (graphical) II - Weatherlink Plot Mode This is a similar presentation to the monthly Cumulus chart above, but from a different program. Plot mode is one of the five main local PC modes of the standard Davis Weatherlink software. This charting mode is notable for its flexibility in easily being able to overlay different parameters and to select different time periods for review. Its presentation is clear and plain rather than Powerpoint 'fancy'.

 

Website Live Data Presentations (also available to networked PCs not directly linked to the AWS logger)

Definitions: With web page presentations there is a key issue about how often you wish the presentation to update automatically (in the context of displaying live weather data as opposed to static historical data for eg last month).

For standard HTML pages the maximum update frequency routinely achievable is around once per minute. However, one update per minute is not sufficient to show live wind data, which requires updates every 2-3 seconds to display individual wind gusts accurately. (And, since wind is the only weather parameter that typically changes on a time-scale of seconds, if you're not seeking to show live wind data then updates say every 5 minutes are often enough to show live weather conditions with reasonable accuracy while making much less demand on upload bandwidth, server response etc.)

It is possible to show live wind data on a website with updates as often as every 3 seconds, but this requires a move away from standard HTML web pages to special add-on software techniques that use Flash or Silverlight. With these techniques, the generation of the visual data presentation is all handled in the user's web browser with relatively only very small amounts of data needing to be uploaded to the web server at every update.

So for web page presentations we recognise two distinct categories of display:

  1. Real-time displays, which will update on a timescale of seconds. These displays need special software such as Cumulus Real-time (Silverlight) and Weather Display Live (Flash) which are add-ons to the main weather processing software;
  2. Current conditions displays, which use traditional HTML web pages and are typically set to update at 1, 5 or 10 minute intervals;

The first four of the examples below are images - click on the image to open a new window with live weather data. (NB You may need to resize the new window to see the full display. Also, if you don't have the appropriate technologies installed on your PC such as Flash and Silverlight then you won't be able to see the live data feeds - most PCs do now have them installed as standard.) For the two final weatherlink.com examples, the live data is embedded in this current web page (using an iframe mechanism) as a demonstration of how this can be achieved.

A notable feature of some (but not all) of the web page displays is that they are user-configurable. What the originating program generates are the individual elements of the display - a single gauge for example - and the web page owner can then customise the layout and appearance of the elements according to their own preferences. This is why web pages using the same underlying software can look distinctly different from one another.

  • Weather Display Live imageReal-time display (graphical) I - Weather Display Live (WDL) This is the most popular of the real-time web programs and takes a data feed from the Weather Display (WD) software. Despite the overlap in names, WD and WDL are two quite separate programs, written by different designers, but working in harness. WD runs locally on a PC linked to the weather station to generate the data feed in a specific format while WDL is uploaded to the web environment to create the final visual display in the user's browser.

 

  • Cumulus Real-time ScreenReal-time display (graphical) II - Cumulus This is a different take on the real-time theme and uses Microsoft Silverlight as the enabling real-time technology rather than Adobe Flash as used by WDL above. In the Cumulus software both the local program and the real-time add-on come from the same software design house.

 

  • Sample WDL image from ElyweatherReal-time display - enhanced (graphical)- www.elyweather.co.uk This example is taken from our own local weather website and illustrates two features. First, it shows how custom extensions to an underlying data presentation can be made. In this case, we've taken the WDL display (see above) as a starting point and added some trend graphs of our own in the left-hand column. And, second, it illustrates how even though we're using the same WDL program as above, by changing the selection, layout and styling of the displayed elements, it's possible to achieve a significantly different look.

 

  • Weatherlink web pageCurrent conditions display (full)  This is an important example because it shows the standard web page display possible with the Davis Weatherlink software that is supplied free with every Davis data logger. Anyone using this program can generate this web page display after just an hour or two's work to set up and test the installation. It's also noteworthy as an illustration of how it's possible to mix three types of element in the overall display:
    • Text values, including highs and lows, in the left-hand column;
    • A visual representation of current weather values in the 'tank' graphics, such as temperature;
    • Trend graphs to show certain readings changing with time as in the barometer trace;

NB This example (and those below) is a 'current conditions' display rather than real-time and so updates eg every 5 minutes.

 

  • Current conditions display (text) - This is an example of the summary screen available from the weatherlink.com website which is uploaded to by the special WeatherlinkIP data loggers and is the companion screen to the graphical current conditions display included close to the top of this page. It illustrates how even simple text can still be a powerful way of displaying current weather conditions, as well as providing high and low values for today so far for a variety of weather parameters. The example below should be showing live data and so also illustrates how it is possible to embed live data in your own web page (via an HTML iframe).

 

  • Current conditions display (enhanced text) - See image with the blue-sky background from the Weatherlink.com website close to the top of this page.
  • [Any of the local PC displays showing summaries over a defined period (eg monthly) can obviously also be copied up to a website/network display, but because these are typically generated interactively with user input and not automatically, they're not in the same category as the preceding four website options, which all upload and update automatically.]