Reflective Teaching Practice (2) - Do I need to Know There is Such a Thing as an R-Tree Index?

I've recently been working on a paper about teaching database and spatial database concepts to GIS graduate students, using a self-paced tutorial, Free and Open Source Software (FOSS) and Open Data (PostgreSQL/PostGIS, QGIS and Open Street Map).  Once of the aims when setting up the tutorial in 2010 was to open the material to other students - i.e. to make it available to non-GIS specialists.   At the time, I didn't realise that that would be exactly what this JISC G3 project is aiming to do to but now I find myself faced with a similar question to the one raised previously on this blog:  

Once we get to including material about Spatial Databases (in an advanced version of G3), what content is relevant to non-GIS specialists?

Here are my first thoughts:


What We Should Include:
I think that any material relating to databases should certainly explain their advantages - concurrent access, central storage, security, single source of truth.  We should also include information about data types - text, number, date, and in particular the spatial data type - how to store points, lines and polygons in the database. Connecting the GIS to the database and viewing and editing the data is also fundamental.  

R-Tree Index (from: http://en.wikipedia.org/wiki/R-tree)

As a more advanced topic, I would also include at least some SQL querying in the material - with links to further information, and some information on indexing and spatial indexing.  These days, students are sometimes dealing with quite large datasets and I think it will be useful for them to know how to improve the performance of their system. So, for me, the R-Tree should be there (yes, it is complicated so perhaps we can leave out the detail?)




What Should Be Left Out:

E-R Diagram (from http://en.wikpedia.org/wiki/E-R_diagram)

I think that for most students there is no need to include concepts of Entity-Relationship diagrams.   Similarly, conceptual, logical and physical design and concepts related to normalisation should be excluded.  Most of the JISC G3 users will be using data that has already been modelled, and very few of them will be collecting data from scratch and therefore require tutoring on how to model the real world in a database.


As you can see, overall I found myself erring on the side of 'include', most likely as I am an "expert" in the subject and for me all of it is important.  I suspect that this dilemma will face us again and again as this project grows and more material is added.  This also highlights the importance of the use-cases and talking to end-users when developing this type of material.  


(With thanks to Kate Jones for the re-use of the title of one of her blog posts.) 

State of the Map EU - Presentation

Just a quick pointer to the recording of my presentation here at SOTMEU. So, far a great and vibrant conference, and our research into usability issues in OpenStreetMap was well received. I was particularly pleased by the positive reaction from a lot of conference attendants to our work, it seems that most core community members are well aware of the issues we raised, and recognise the need for improvement.

This small research project from us then represents the first of an ongoing effort to better embed and implement a usability engineering culture in this great project!

GIS are still hard to use! The interface design of a desktop GIS ensures they are NOT easy to learn....

Desktop Geographical Information Systems (GIS) are not user friendly they require time and effort to learn and remember. They are not intuitive and for new learners the first time they are faced with a GIS can be overwhelming experience, where do you start? These difficulties are nicely summarised in the user interviews I have been conducting.

One of our specialist users described their first and so far only encounter with a GIS. They were looking to just explore what the software could do – without being able to dedicate any real time to learning it. They successfully downloaded some geographically referenced data from Digimap (it was actually MasterMap). They then started the GIS programme and spent 5 to 10 minutes trying to open the data that had just obtained, in that time they did not succeed to open the data so they gave up and made their map in Photoshop. They found GIS too difficult to use. From a usability perspective this represents an issue in learnability. The design of the desktop GIS meant that the new learner failed in the first hurdle- adding existing geographical data to a map.

The notion that desktop GIS are hard to use is not new. More than 15 years ago in 1995 Traynor and Williams discussed the issues of usability in GIS presenting a paper with the title, "Why Are Geographical Information Systems hard to use?" at the annual ACM conference on Human Factors in Computing Systems.

Today, desktop GIS are still just as difficult to use!! The interface design really does not make them easy to learn. Will this change as the development of VGI web-mapping interfaces progresses since they rely on contributions by the general public?

Open Street Map: State of the Map presentation

Just a quick note from the JISCG3 team, Kate and Myself we will be presenting our usability research on VGI editors at the the 1st European State of the Map Conference of the OpenStreetMap project held 15th-17th July 2011 in Vienna, Austria.

The talk will draw upon our previous work in evaluating the usability of the Potlatch editing environment, an online data editing interface for OpenStreetMap.

This presentation presents one of the first systematic investigations into the usability of Volunteered Geographic Information (VGI) editor front-ends, using established best practice in Human Computer Interaction (HCI) research. The two front-ends evaluated are Potlatch 2 and Google Map Maker, to present contrasting views of the user experience of two major VGI projects. Two user groups with no prior experience of VGI contribution were instructed to enrol and contribute data to both VGI projects, and their interaction with the two services were monitored using a mobile eye tracker and video screen capture software in a computer lab environment. The resulting data was analysed to reveal how users interact and experience VGI editors, as well as highlight deficiencies and differences between Potlatch 2 and Google Map Maker. The results from this research project are a set of recommendations for the future development of these editors, specifically relating to improving the user experience and ease of use of VGI editors.

The talk will be recorded and hopefully put online after, I will link on this blog to it as soon as possible afterwards.

Hope to see you there, and looking forward to the discussions!

Prioritising Geographic Concepts for Teaching New Learners GIS: results from our blog poll

We asked readers of the blog to identify the priority of teaching certain Geographic Concepts to new users whilst quite a few people viewed the questions only 21 readers completed the poll. Firstly, I would like to thank the blog readers who completed our quick survey. The table below summarises the concepts that we used in the poll. A graph at the bottom of the blog post shows the results.

Geographic Concept	Details	Example
Beginning mapping	importance of location	zoom, pan, layers
Geographic data modelling	raster versus vector	Points, Lines, Polygons and Pixels....
Cartographic theory	fundamental principles of cartography	simplicity, harmony, no map junk ...
Data generalisation	introduction of types of and need for generalisation	Simplification, Selection, Omission, Displacement, Aggregation...
Data classification	introduction to data classification rules and type of classification	Natural Breaks, Quintiles, Geometric Progressions ...
Mapping conventions	elements that enhance user understanding of the map	scale bar, legend, north arrow, symbology....
Simple spatial analysis	introducing simple analysis computed using GIS	buffer, distance, overlay....
Uncertainty in geographic data	Impact of uncertainty on data	Modifiable Areal Unit Problem, ecological fallacy

With such a small N we do not have a any statistically valid results but what we do have is some useful thoughts that support the thinking of the project team and the development of the scenarios and resulting site development.

We asked readers to prioritise the concepts based on a linear scale of 1 to 5, where a score of 1 represented a concept that was not relevant to new learners and a score of 5 signified a must teach concept for new users. Using these values, I have calculated a quick and dirty Score of Importance for each of the priorities, see the graph at the bottom. This score alongside the free text comments helps us to identify quickly what our readers think are the most important concepts to teach new learners of GIS.

Results :

• All of the concepts are relevant for new users of GIS to learn – but the timing of when they are introduced is what is most important
• The most important concept is associated with beginning mapping and why spatial is special
• New users need to be aware of the issues that result because GI models are simply an abstraction of reality and they need to be familiar with how reality is represented using data models.
• Principles and practical cartography were rated (slightly) more important to teach before introducing simple spatial analysis and uncertainty
• The details of datums and map projections are beyond the scope but it is important for users to recognise the internal bias that may result from a map projection

Metaphor for Introducing & Teaching Map Projections: The world as a Piece of (Digital) Graph Paper

The ins and outs of projection systems can be complicated to introduce to new learners of GIS – and how much do you really need to know to create your first map? Over a coffee in the sunshine (it was hard work teaching summer school in Malta) Claire and I were discussing the question: How do we introduce map projections to new learners?

It turns out we both start with a demonstration. Claire uses her fist to represent the globe and her other hand to represent the piece of paper that is then wrapped around the globe (somewhat like the rock, paper scissors game). I on the other hand use a Clementine and a piece of paper – the paper crumples resulting from wrapping the paper around the Clementine represent the distortions that occur during the projection process. We both then go on to talk about grids etc...

Both of these illustrate the problem of modelling a complex reality in 2D. So if new learners imagined that a giant piece of graph paper is wrapped around the globe and that each place on earth is then marked on the graph paper it is possible to visualise the fundamentals of digital mapping.

The map window in a GIS is in essence a sheet of digital graph paper. One possibility is to harness this metaphor in our tutorials. Projection systems can be introduced simply within our scenarios, perhaps by activating and showing the grid (ie the sheet of graph paper) and asking the user to observe the coordinates changing as the mouse is moved horizontally and vertically.

It is important to understand the basics if you are using data that is not GIS ready. For example, one of the practical’s I have designed for the International GIS summer school at the University of Malta that I teach on uses a data set of road traffic accidents in England (from the UK open data initiative). The text file contains the X,Y location of each accident as an attribute field. In order to create point data of each accident the students need to know:

• 1) Why there is such a thing as a coordinate system?
• 2) How to identify fields containing coordinate data in the data set?
• 3) What coordinate system the fields represent?
• 4) How you can view the coordinates change as you move the mouse over your map

Reflective Teaching Practice: Do I need to know there is such a thing as a map projection?

Myself and Claire have just arrived back from the Island of Malta, where we both participate in the International Summer School in GIS held at the University of Malta. We both design and deliver lecture material targeted at professionals who are discovering how GIS maybe useful.

We were discussing our observations of the students and how they learn and interact with the GIS software and its theoretical principles.

One subject up for debate was, "do new learners of GIS and its concepts need to know immediately about projections?" There is a tendency to be puritanical about what concepts new learners of GIS need to understand putting aside this tendency, our conclusion was: “Not necessarily”.

Let me explain. Most everyday users of Bing Maps, Google Maps etc interact with the map quite happily without needing to know that a projection system makes it possible to create the digital representations of the world. The same can be said for users of navigation systems in cars or on phones.

Therefore, it is only natural that a new user of GIS, creating their first map using off the shelf Shape files or MapInfo Tabs (for example taken from Edina’s Digimap service), does not need their first interaction to introduce the complexities of coordinate systems that enable real world to be projected in 2 dimensions. It is only when their data they want to map is not GIS ready that they need to be introduced to a projection system.