Here are answers to some of the most frequently asked questions and other issues that were brought to our attention by our users. Read this page first before sending any further inquiries through our contact page.

1. Who or what is Worldmapper
2. You have found a mistake
3. Map questions
4. PDF Poster questions
5. Data file questions
6. Data questions
7. Copyright
8. Making your own maps/requesting maps
9. Help

1 Who or what is Worldmapper

Worldmapper is a non-­profit mapping project. It started as an academic project at the University of Sheffield with funding by the Leverhulme Trust and further support by the University of Michigan and the Geographical Association. You can view the group of people who helped set up the original project in our archive here.
After the funding ended, we converted Worldmapper into non-for-profit social enterprise which got registered with Companies House in England and Wales in 2014. This helped us to raise new funds to cover some of the maintenance cost of our web server and to finance technical equipment and software licenses through the sale of map use licenses for commercial use. This also allowed us to finance the development of our new website and develop the new series maps which you now find on Worldmapper.org.
Worldmapper continues to be free to access and use for non-commercial purposes (including educational use in teaching) under a Creative Commons license (CC BY-NC-SA 4.0), as it has always been. In addition, we now sell map use licenses for commercial purposes and also offer other cartographic services. Any income made goes straight into the maintenance of our website als helps us to keep the website up and running and continue working on new material.
You can also support Worldmapper through a Paypal donation.

2 You have found a mistake:

Maps, posters and files are put on the website after initial checking before going through a series of further checks. Most errors will probably be corrected within a month of their first appearance. Currently all maps etc. can be changed if errors are found. Please let us know (Contact us here) of any particular mistakes requiring your expert knowledge to spot or if you think you have spotted an error that we have missed. See section 8.6 about data errors.

3 About the Maps:

Q. What are all these strange maps?
A. They are cartograms, where the territories have been re-sized according to a variable.

Q. Why do you use the term ‘territory’? Why not ‘country’?
A. Most of our territories are considered independent countries, and all 191 recognised by the United Nations are included. However, we include some other territories that, whilst not recognised as independent by the United Nations, might consider themselves to have some degree of independence. Some of the territories we include may not be recognised as independent countries by other territories. Our main criteria in including a territory is that it is distinct enough for us to obtain data for that territory.

Q. What do the colours used on the maps represent?
A. A consistent colour scheme is used throughout all the country-level maps, tables and spreadsheets in Worldmapper. We used the United Nations Geoscheme for dividing the world into main regions with one adjustment of allocating Greenland to Europe instead of North America. Each region has one main hue, while subregions are differentiated through different intensities of that colour. A reference map can be used alongside the cartograms to aid orientation.

Q. Why don’t you have a map of population density or births per thousand?
A. Cartograms are best understood as pie charts where the segment of the pie is reshaped to look like a country.  Then the area of that country is adjusted according to the proportion of the world total of a variable that is found there.  Just as a pie chart would.  As such, we can only map counts or totals.  We cannot map rates because they are not additive, that is to say that they do not add up to a meaningful total.  To return to the pie chart analogy, you would not draw a pie chart of population density but one of total population. In some maps we use relative data that we display on top of a cartogram, so that rates can also be shown using this mapping technique.

Q: I cannot tell which territory is which.
A: There are many ways to identify a particular territory:

Q: Why don’t you put territory names on the maps?
A: 200 legible names the same size would obscure the maps. If shrunk to the size of each territory, most names would not be legible on maps smaller than A4. We have produced a reference map and we are working on another reference map, on which all but the smallest territories will be labelled.

Q: How do I compare two maps on the screen at the same time?
A: If you cannot view two web pages simultaneously, try

Q: You have used Mercator’s projection! Why?
A: No, the original projection was one that is similar to Peters’ projection which is an equal area one. You could stretch the maps vertically or horizontally and all the areas would still be in correct proportion to each other.

Q: Almost all the maps have sea, which is meaningless except on the land area map. Why?
A: The sea makes it much easier to maintain recognisable shapes to the territories, and avoids those separated by an ocean from touching each other. The sea is given a fixed total area, although the area it fills adjusts to the changing shape of territories. The total area for all territories is also the same on all maps, just divided up in different ways

Q: The maps have no scales! And no north arrow either. Why?
A: With the size of the sea and entire map help constant, territories are drawn in proportion to the variable in question. The area of the entire map represents approximately 3.4 times the world total of the variable. In using a social variable rather than land area to scale the territories, it is the relative sizes of the territories that becomes important. A north arrow would equally be meaningless, as north is not consistently on top where country shapes are wiggly and distorted.

Q: The world and territory totals are not always given in the accompanying text. Why?
A: All the figures for the world, each region and every territory are available in the data sheet of the data file for each map. The cartograms convey the comprehensible relative proportions: if Angola is twice the size of Zambia then the variable in Angola is twice as large as in Zambia. This comparison between territories can be more informative than the absolute figures, which are frequently unimaginable large numbers (billions of dollars for instance).

Q: Why is the population of Alaska so large?
A: Because it is treated as part of the shape of the USA and is not disproportionately shrunk because of internal regional differences within the USA. Only the gridded cartograms treat Alaska (and any other part of the world) geographically exact in its data distortion.

Q: Is the data accurate.
A: No.
For data to be accurate, all 200+ territories would have to produce data for the same time period, by the same method, and by a method which is accurate. Apart from gaps in the original data sets, the method frequently only gives an approximation, and methodologies can vary, producing different results. To get around the last problem, UN agencies sometimes give estimates in preference to territory-supplied data. We make estimates from data from different years when available or use other countries that are similar as a proxy. The nature of the maps makes it necessary to produce figures for all 200+ territories, and the technical notes in the data sheets say how missing data has been dealt with.

Q: Why do you make maps with inaccurate data?
A: We think the overall impression given by each map we produce is unlikely to be different from a map based on accurate data, if it was available (which it isn’t).

Q. When will you finish the maps off?
A. Since our relaunch we are now approaching the first 1000 maps and have already exceeded the number of maps that were on the original Worldmapper website (which can still be viewed with some technical problems in our archive). We will keep mapping new data as much as time allows us. Worldmapper is now run in our spare time and as we are putting our own time and resources into it, our activity levels may be variable. If you like what we are doing and want to support us, please get in touch!

Why no maps with the southern hemisphere "on top"?
A. People are familiar with the northern hemisphere on top, and while we obviously encourage the use of maps with a different viewpoint, if one aspect is changed (territory size), rather than many, the reader still has a frame of reference from which to interpret the map. We may consider producing some maps with alternative viewpoints in the future.

Q: Which maps are comparable?
A: Because every map shows just the worldwide distribution of one variable, any maps can be compared however different the units used for the data are.

4 About the PDF posters:

Q: I can’t download the PDF poster.
A: The posters are large files, and will take time to download, especially on a dial-up link. You will also need Acrobat Reader to view the file.

Q: Why is the file so large?
A: The resolution is high. Try Adobe Acrobat’s magnifier. With a reasonable colour printer and photo quality paper you can produce a colour, atlas quality, printout.

Q: Where have the posters gone?
A: We have produced a few new posters of already, such as for Population 2018, but time constraints mean that at the moment we prioritise the development of new maps to making posters. We hope to create new posters of key maps in future.

4 About the Data files:

Q. I don’t have Microsoft Excel – how can I view the data files?
A. You do not need Microsoft Excel to open our Excel data files. A free cross-platform alternative tool is LibreOffice.

Q: There are more than 200 territories in the world. Have you forgotten some countries?
A: In all the rest that we have not included are less than 0.05% of the world population, so their inclusion would rarely affect the overall figures or appearance of the maps.

Q: I can’t read some of the data because of the background colour.
A: Click on the cell, and its content appears without background colour in the formula bar.

Q: The value in the cell says 0.
A: Click on the cell, and you will see the value to 2 or more significant digits in the formula bar. Alternatively alter the number of decimal places for the whole column. Otherwise the data value may indeed be 0.

Q: Will you be putting all the data in a single master file.
A: As we constantly produce new maps, we do not plan on doing that.

Q: The Excel files say “Read Only”.
A: We regret this sometimes happens. You could try saving the file (‘right-click’ in Windows) rather than opening it. In fact you can still sort, alter and save them as normal.

Q: What are the technical notes?
The technical notes are included in a separate data sheet within the Excel data file. These provide the data sources that we used, when and where we accessed them, as well as further descriptions where appropriate. They also contain explanations about any estimations and changes that we may have made to make the data suitable for our mapping purposes.

6 About the data:

Q: Where can I find the figures you used for the maps?
A: The data sources are documented in the data sheets that can be downloaded from the technical notes box on each map page. The technical notes also include a link to the data source that we used, and when we accessed the data there (if it was obtained online).

Q: What happens to the map if the value is zero or negative for a particular territory?
A: The territory becomes an almost invisible line. Negative values cannot be mapped here because we cannot represent negative area. As such all values that are negative appear the same as a value of zero on the map.

Q: What happens when there is no data available for particular territories?
A: This varies depending on the variable in question. We try to avoid giving a territory a value of zero just because it has not provided the data to the relevant UN authority or other data source, and make various assumptions described in the technical notes to make a provisional estimate. Often these estimates assume the rate of the region in which a territory is located. Sometimes the UN authority does not ask for data from certain territories as the figure is likely to be so near 0% or 100% of whatever – so as to be irrelevant in a world context.

Q: I want to find all the figures for just one territory.
A: Unfortunately have to look these up separately in each individual data file.

Q. Where does the data come from to create the maps?
A. Various sources. For more detail see the technical notes on each map page.

Q. Do you really have all this data for all of the territories you have mapped?
A. Our data files show data for 200+ territories, covering the vast majority of the world’s population. For many of the data files, we have had to calculate an estimate for some of the smaller territories based on the regional average. See the the data files for more details of how we addressed data gaps.

Q: The data is wrong.
A: If the data source given in the technical notes has published incorrect data, please contact the source directly. If we have used regional averages or just put zero, please let us know (contact us here) of secondary data sources for missing territories.

7 Copyright

Q. Can I use these maps in my own work?
A. All our maps are published under a Creative Commons Attribution – Non Commercial – ShareAlike 4.0 International License. For any commercial use (including in publishing) a map use license needs to be obtained. You can print maps and posters out for your own or educational or other non-commercial use. If you wish to use the maps for any other purpose (including publishing), or would like to obtain high-quality TIFs of just the maps, you may purchase these from the purchase option that is provided on the individual map pages. A purchase gives you access to 300dpi resolution TIF images. If you have further questions about copyright or obtaining licenses, please contact us.

8 Making your own maps/requesting maps


Q. Can I produce my own maps like these?

Worldmapper maps utilise a cartogram algorithm developed by Michael Gastner and Mark Newman which is described in this paper. See the links below to get access to various implementations of the code. More recently, we have also implemented Michael Gastner’s new Fast Flow algorithm.
You may need experience in working with GIS and also some coding and cartographic skills to be able to utilise these techniques. We ask for your understanding that we cannot provide assistance or technical support in creating cartograms, using GIS or other cartography-related matters, but we are able to provide consultancy services for a fee.
External resources:
Gastner/Newman cartogram code
Gastner et al. Flow-based cartograms (Github)
Esri ArcGIS tool

Q. If I supply some data, can you do a map for me?

A. We work on Worldmapper in our spare time and have other jobs to make a living. Making maps can be a time-consuming effort, so that we are not able to offer any free cartogram or other mapping services. We may be able to help but will charge for our services which we use to keep this project alive. If you want to discuss any cartographic projects, please get in touch via the contact page.

9 Help

Q. I have other questions that are not answered here.
A, See answer 8.1 – you may still contact us if you have had a comment, problem or query not dealt with here but our capacities to reply are very limited and we ask for your understanding if we do not reply to all emails or if an answer takes longer than you may have been hoping for.

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