If from Lab 1 we learned, a typical GIS map is supposed to have:
Bare in mind, there are some 'wrong' answers to some of these questions and choices in terms of map layout and what map elements to include. However, there is rarely a single 'right' answer and often you can justify inclusion or exclusion of different map elements based on the context (remember the 6 C's). Is this subjective? Of course it is! But, we pose some questions and 'rules of thumb' below to help you make that judgement call so that your map is convincing for the audience it was intended for. To get a feel for hyper-critical critiques of maps, I strongly suggest you browse around or subscribe to http://cartastrophe.wordpress.com/.
Lets go through each piece:
A big title on a map is not necessary when:
You may want to use a title if the map is a stand-alone static map. The title in Figure 1 above is not necessary if the figure is used with a caption that tells you the same thing. Sometimes, sub-titles are helpful to have on a multi-part figure (e.g. those in Figure 2 below) so that the reader can differentiate between the different maps being compared quickly, without reading the caption.
Sure, north arrows and scale bars are generally necessary*, but what if I'm making a figure that is a comparison of four maps, as in figure 2 below? Should I really have four north arrows, when north is always up the page? I need one, but not four. If you have multiple maps or inset maps in a figure that are at different scales, make sure each has its own scale bar. In the figure below, A & B are the same scale, and C & D are the same scale
*Arguably, they aren't always necessary. When identifiable outlines (state, country, etc.) are visible and recognizable to your audience, north and scale can be easily ascertained.
This is where context (6 C's) comes in. If you've already shown the location or vicinity map earlier in the report, manuscript, website, etc., do you need to show it again? Often, in reports and manuscripts, a stand-alone location map is shown early on in a 'Study Site Description' section, for example. In instances where there may only be one map figure or no room for a stand-alone location map, an inset location or vicinity map is sometimes used. It might be helpful to first review the difference between a location and vicinity map.
A legend is not always necessary for a map figure (e.g. Figure 2 shows only aerial photos so no legend is necessary). There are also some data sets where the symbology shown is so simple that it does not necessitate a legend or can be easily explained in the caption (e.g. 2 -3 categories) or with labels on the map. The placement of the legend and symbols (if used) should always be done as to not detract from the overall map nor make it the focus. The legend provides context and gives meaning, but should not be the main thing your eye is drawn to. In multi-part figures and maps that use the same symbology, the legends do not need to be repeated.
Color choice for color ramps or classified colors is critical to making an effective map. Cynthia Brewer did a whole PhD on the topic. Her work is represented in a fantastic interactive website called Color Brewer. What Color Brewer does is helps you choose colors for categorical color schemes that will contrast effectively, and are pleasing to the eye. You get to choose how many classes, whether you want a sequential, diverging or qualitative color ramp, and then it even lets you restrict choices to 'colorblind safe' , or 'print friendly' or 'photocopy safe' choices. You can then export the colors and use them in ArcMap or Adobe Illustrator directly.
Color Brewer is so easy to use, it hardly needs explanation, but if you want a step-by-step on how to use it with ArcGIS, here you go:
It is sometimes considered best practice to denote information about the coordinate system and datum you used in a caption or note (often in one of the lower corners) of a map. This is one where context comes into play. If your audience is or includes GIS Savvy readers, you may choose to list this information in a caption. However, in many instances information about the projection really does not make a big deal (e.g. Figure 3 above or Figure 4C below). Ask yourself if the meaning of the map is fundamentally different if it was displayed in one coordinate system or another (state-plane versus UTM, for example)? One case where it does make a difference is when you are using a grid or graticule. The labels in the grid (e.g. Figure 4A below) don't have much meaning without the context of which coordinate system they are in or units. Plus, when a grid (Figure 4A) or graticule (Figure 4B) is used, you can avoid the need for a location map because this spatial location information is explicitly shown. We learn more about using grids and graticules in Lab 3.
Figure 4 - Contrast between needing to report in caption that this the coordinate system was UTM Zone 10N, NAD 83 Datum and not. For A, which shows a grid, this information is essential. For B, which shows a graticule, this information is optional. For C, this information is not necessary.
If you are using data sources (e.g. aerial imagery) or other data layers that you did not produce or collect yourself, you should always cite them somewhere.
Figure 5 - Our LibGuide for this course, which covers where to find GIS data sources and how to appropriately cite them.
Whether or not a this is a necessary element of every map or figure that includes a map is very context specific.
What I typically do not want to see on your maps is something like:
It looks like something a introductory GIS student would do (I know.... I know... some of you are!). Leave it out. If you want to put something like a watermark or transparent copyright (e.g. © Joe Blow 2013), you are welcome to. However, context matters again here. If you are preparing figures for submission to a journal, the publisher will often require you to grant or transfer the copyright to them prior to publication. If it is our own website, you may have a blanket copyright to the whole website. If it is going to appear on someone else's website, you may want something more specific.
Figure 6 - Subtle use of a copyright symbol and acknowledgement of who produced the map.
See this for ColorBrewer color ramp suggestions.
Be careful not to have unneccesary white space around the perimter of your maps and figures. When you insert figures into reports, manuscripts, webpages, posters and presentations, there will likely already be white space and borders. If your figures have additional white space on the perimters, it has the effect of just making your images look smaller on the page.
Figure 1 above does not have a caption (as part of the figure), and even on ESRI's website, it does not include a caption below it. I would encourage you to typically NOT include captions in your figures (i.e. in the image itself), but always use captions where you use the figure in a report, manuscript, poster or webpage. In presentations, captions typically are not appropriate. Depending on the context, it may be helpful to include a caption in a stand-alone map or figure, which you do not know how it may be used.
Where captions are used, they should be informative and help a reader understand what is being presented in the figure. Below in Figure X is a multi-part figure in which Olden et al. (2012) show two related maps that leverage data from other published papers and data sources. This illustrates nicely how you can re-use and appropriately cite existing data sources and published data sets with proper attribution.
Figure X - The figure above is from a refereed journal publication in the journal Ecohydrology and illustrates the use of an informative caption. The figure and caption was reproduced without permission from Olden et al. (2012) - © 2011 John Wiley & Sons . Click on image for larger view.
Olden JD, Kennard MJ and Pusey BJ. 2012. A framework for hydrologic classification with a review of methodologies and applications in ecohydrology. Ecohydrology. 5(4): 503-518. DOI: 10.1002/eco.251.
When you do cite someone and provide a reference in a website, you should make those citations more useful to your audience by providing hyperlinks to them. For example, in the above example I have provided a hyperlink using the DOI (digital object identifier - a permanent stable URL) in both the citation to Olden et al. (2012) as well as the reference.
See here for more information on using citations in your writing.
For this class, you are not required to copyright your work, but you are required to share your work on your own website. However, you may want to copyright your work to protect yourself (especially if your website is open to anyone in the world). If you do copyright your work, you need to take extra precautions to make sure you are citing any other copyrighted work or data sources you might have used in preparation of your own maps and figures. Here are some things to consider in different contexts:
You can over-do it on copyrights too. Some people find copyrights plastered all over the place distracting. Use common sense and place your copyrights subtly (so they are there if anyone looks for them, but don't necessarily grab your eye). Using transparency can help make them subtle.
Subtle: © Joe Blow 2013 Obnoxious: © Joe Blow 2013
There are many ways to share your work in a manner that protects your legal rights and copyright. Perhaps one of the simplest of these that is specifically geared towards sharing your creative works (particularly digital media and data) is a Creative Commons license. There are six types of licenses you can use, which allow you to choose whether or not others simply have to attribute you, whether or not they can derive their own products from your works, whether or not they can use them commercially, and how they must share their derivatives (if allowed). What's nice, is you can create your own Creative Commons license easily here, and apply it to a whole website or just a single figure or map. This is an example of what a Creative Commons license looks like (the one I used for this site):
Example Figure by Wheaton is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Based on a work at joewheaton.org.
This is the form you fill out to create your own:
FigShare. One of the advantages of using figshare, is you can get a permanent, stable DOI and URL, as well as providing people with a simple way to cite your work. One of the disadvantages of figshare is once you post something, it is permanent and you can never remove it from the public domain.
Ahead to 2. Planning your Figure Layout ->