Getting Ready for the Lab
Connect to Osmotar and open ArcGIS Pro, and make a new project on your K drive.
Confirm that you are logged into the UNBC GIS Lab Portal; you should see your name in the upper right corner.
If you are signed out when you log in make sure the sign-in dialogue says UNBC GIS Lab
If you do not see the portal listed, follow the steps to add the portal from lab one, copied below:
Select Portals, Then Add Portal and set the URL to https://arc.gis.unbc.ca/portal
Right Click on the portal you just added, set as active and sign in
Your username is your UNBC username, followed by @UNI, and then your regular UNBC password.
Use the back button in the upper right corner to close settings
1. Nominal/Categorical Symbology
Choosing Colours for Nominal Data:
Colour Philosophy: The basic approach to symbolizing nominal categories is to use random colours: no colour within the group should advance (“pop” out). No two colours chosen for the symbol set must be too visually similar. In a complex map with great detail, it would be difficult to tell polygons apart first because the human brain can’t retain the visual information long enough while looking from the map colour over the legend and back again to discriminate similar colours. Second, when surrounded by other colours, the colour of a polygon experiences a colour shift, which compounds the colour matching problem between the legend and the map polygon fills. A third complication arises as a colour on a computer monitor is flooded from behind by the screen’s light, and that same colour on a paper print is created by pigments on a page reflecting light. A single colour can look different based on its medium. This may cause a computer monitor designed colour to look darker on the printed page (or paler) than intended and may cause two or more colours to be difficult to visual discriminate on the printed map and match to the legend.
Do not use darker shades of one colour in a nominal symbol fill set (for example, multiple shades of green) since increasingly darker shades of one colour are used to symbolize magnitude (interval) data as “darker” means “more.”
As an example of this let us open the Provincial Boundaries layer from the ArcGIS Portal
symbology type to Unique Values
Set Field 1 to PRNAME
This doesn’t display any more information than before, but the random colours add more contrast between the province and should seem very familiar to the type of national maps you would have seen in primary school.
2. Symbolizing Areas by Quantities
We will start our journey into thematic mapping using colours set from values in a layer’s attributes. This data will often come in two parts, first is a boundary layer generally these can be found on government websites such as Census Canada: https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/index-eng.cfm
Start by adding the provincial boundaries to your map, available in the UNBC GIS Lab portal as “Provinces with population 2020”.
Right-click on the newly added layer and view its attribute table; take a look at how many columns are present.
Next, we will get the actual thematic data this generally comes in the form of a spreadsheet (remember the CSV files from Lab 3). Or in this case, we will be using an ESRI DBF table.
Canada Energy Usage Data 2020 table is available on the L: drive
At this stage the drawing order of your map should appear as below
Notice that the CanadaEnergy2020 is listed as a stand-alone table, this is because there is no spatial information with this layer. To draw this on the map we need to “join” our layers together. Right-click on gpr_000a11a_e (Stats Canada name for the Provincial Boundaries), and find the option to add a join.
The join tool will take two tables, and a column from each that has Exactly the same text and add the columns of the join table to the end of the Input table. Note this is case sensitive so when you download your data you may need to edit names to match the boundary files you have.
For our case PRNAME column exits in both tables so we will join on this.
Press ok, and now look at the attribute table and confirm that the extra columns have been added to the attributes.
Now go into Appearance > Symbology > Unclassified Colors
Start by setting the field to demand
Now when you look at your map you should see the first problem when working with this type of data. The Territories all appear white, as well as Saskatchewan and Manitoba appear the same shade of light blue. What the map is really showing us at this point is how uneven the spread of population is across Canada. Whenever you are working with this type of data take a moment to consider what variables may be driving the numbers you are trying to graph.
To make this map a little bit more interesting change the field to “percapa” this field shows the energy used per person in each province in 2020 (note no units of energy were provided with this dataset).
This data came with a normalized dataset already, an alternative option would be to select demand and normalize it against the population.
Next let us take a look at the Color Scheme you can pick several from the drop-down, or press the ‘Format Colour Scheme” at the bottom of the drop-down to be given a window that allows for selecting custom colours at intervals across the gradient. When picking your Colour scheme your primary focus should be that the colours are intuitive! Going from green to red will convey a very different meaning than red to green. Secondly, you should pick a Color Scheme that fits the theme of your map!
Lets look at a couple examples below of how a poor choice can show the wrong message:
3. Proportional Symbols
- Symbol size measured in the area should reflect the values being represented.
- All symbols should be visible. The smallest symbols should be bigger than dots.
- Where there is overlap if any, the smaller symbols should retain their outline to give the visual impression of being on top
- The circle is the standard proportional symbol, but in some cases, other shapes may work better.
ArcGIS Pro Proportional Symbols
To take a look at proportional symbols, we are going to add some XY data to our map, you will find the layer under L:\GEOG205\lab05\postsecondary\NewBrunswick Universities\Sheet1$
This layer contains the 3 universities in NewBrunswick that have a postgrad program as listed by Wikipedia(https://en.wikipedia.org/wiki/List_of_universities_in_Canada).
Once you add the layer go to Appearance > Symbology > Proportional Symbols
Finally Set the field to Total [number of students]
And pick a colour and shape you list by clicking the symbol beside template (circles are generally a good choice!)
Add labels as we did in previous labs and you should have something as below.
ArcGIS Pro Graduated Symbols
All we are going to talk about on Graduated Symbols, is that they work the same as proportional except are placed into classes instead of a gradient. You have already used Graduated Symbols on the roads in Smithers for Lab 4 so we will not be revisiting this today.
Continuing with the New Brunswick Universities, wouldn’t it be cool to know the proportion of grad to undergrad students? To do this under symbology choose charts
Set Chart type to Pie Chart
Fields will be Undergrad, and Postgrad, you will also need to increase the Minimum size to make the charts easy to read.
Finally you may wish to set Display options to Clockwise so that the chart starts at the top
Discussion: What is wrong with the legend below?
Using both Scale and Colour
The keen among you may be wondering why there is a need to chose between Graduated Colours and Graduated symbols. The answer is you don’t need to choose. Start by styling based on one attribute as above, then click on the Vary Symbol by Attribute Button.
If your primary symbol type is colour based you will be able to set a proportional size field. If your primary symbol is size-based, you will be able to set an unclassed colour ramp field.
* Note that only the primary symbol type allows for graduated classes, secondary fields will always be a continuous data range.
Sometimes you simply have too many points, an example of this would be the Lower Mainland (Vancouver BC) crash data from ICBC.
Add Lower_Mainland_Crashes_data.csv to your map as XY point data.
Once this data is added the points are so dense that you can’t really tell what is happening.
To fix this select Heatmap from the symbology panel.
The settings in here are
- Radius – Determines how far to search for nearby points
- Weight Field – This is set to crash count as each point can represent more than one crash.
- Colour ramp – Same as we have seen in the lab so far
- Method – Choosing Dynamic recalculates the colour ramp based on the data visible on the screen. (Increased contrast as you zoom in).
Here is a trick on how to soften the edges of your color map:
Inside of the colour scheme, this ramp has the rightmost colour chip as red with 15% transparency to help the labels be slightly more readable.
The left-most chip is 100% transparent, the chip just slightly to the right is at 85% transparent. This positioning causes the transparency to shift rapidly at low densities into fully transparent ‘feathering’ the edge of the heatmap.
Assignment #5: Due at the beginning of next weeks lab
For your maps this week pay particular attention to the overall aesthetic of your maps. Along with your maps include 1-2 paragraphs about why you made the design decisions you have made. What meaning do colours and fonts convey? How do colours work together? What prompted your decisions on where to place elements such as legend and scale bar.
If you are looking for a way to find colours that work well together consider using a colour wheel (https://color.adobe.com/create/color-wheel)
A – To achieve an A on this assignment see B below, with the addition that colours and fonts work well to convey the meaning of the map. A basemap that matches your colours and labels has been chosen. Design is cohesive and conveys the ‘feeling’ of the map. Elaborate in your paragraph provided with the maps
B – Map contains all required elements and is laid out easy to read, free of formating mistakes on labels, and scale bars. Symbols used to make logical sense, and not overly messy.
C – Map contains all required elements listed in the assignment
D – Maps are missing required elements
F – Maps do not serve the intended purpose
- Export your maps as a pdf following naming conventions for the course
- All maps for this course must contain a Title, Your Name, and the Date you produced it
- All maps must include a scale bar
- Make sure your map is visually pleasing, you have colours, fonts, borders, and multiple base maps at your disposal. (Some of the base maps are very simple in design with very few to no labels, this can be a benefit on thematic maps in building your overall look)
- Proofread your PDF before uploading to ensure that the formating survived the export, if something isn’t looking the way you intend to reach out to your TA for help
Quantity map of Canada Median Income 2015
Map using a colour gradient to how Median Income in Canada by province. Elements should include Title, Scalebar, and a legend.
Heatmap of Peru Seismic events
Data: L:\GEOG205\lab05\Asignment\eventos_sismicos (UTM 18S)
Produce a heatmap of the Seismic events in Peru map elements should include Title, Scalebar, and a legend showing the intensity scale (not absolute values so labelling high and low would be appropriate). You may choose to use Magnitude as the weight (as we used count for crashes), however, your title should reflect this choice (are you mapping frequency of events, or total activity).