Book Review: Learning QGIS 2.0

The best place to discover QGIS is "Learning QGIS 2.0" by Anita Graser for its brevity and attention to detail.  Making great maps using QGIS, a free and open source desktop GIS, is only a few steps away using this book.  Released in September 2013, it is the most up-to-date reference on how to get the results you want using QGIS.  I finally had a chance to read the e-book in its entirety and here is what I think.

The book was written for a range of audiences--including newcomers and more seasoned veterans.  It covers basic and advanced topics from installing QGIS, whether a user or developer and  Ubuntu/Linux or Windows, to adding and editing map data.  In addition, the book contains color screenshots to illustrate what actions are being performed.

The book proceeds logically and words are used efficiently. It helps users add different types of GIS-related data, understand how QGIS treats projections, and highlights vital mapmaking tasks such as symbolizing and labeling.   It also covers QGIS' plugins, notably the Open Street Map plugin for using common basemaps and the Heatmap plugin for density analysis.

Later topics include using the Map Composer (analogous to Layout View in ArcGIS) and the Graphical modeler (Model Builder in ArcGIS). 

Two potential criticisms of open source software are that they tend be harder to use than their paid counterparts.  In addition, some programs lack easy-to-read and authoritative documentation.  With "Learning QGIS 2.0", these barriers no longer exist.   The timing of the book could not be more perfect with the release of QGIS 2.0 Dufour.

When you finish the book, be sure to visit Anita Graser's blog at: http://anitagraser.com/.  It is a real treat!  There you can gain even more advanced knowledge.

To purchase Learning QGIS 2.0 visit Packt Publishing or Amazon.com and Kindle.  The book is available both in e-book formats and physical paper copies/softcover.  E-book formats run about $12.  You can also get a physical copy of the book and all e-book formats for ~$25 on the publisher's site.  Released Sept 2013, 110 pages.

Available from Packt Publishing and Amazon/Amazon Kindle

Fighting the MOOCDEMIC with Open Source GIS

The MOOCDEMIC, billed as the world's first online epidemic, is an web-based app that simulates infectious disease dynamics--part of a Coursera course.  Coursera courses are free massive open online courses. 

Moreover, the app is also GIS based and anyone can participate.  Participants "scan" for infection from their present position with a mobile device.  How cases are being seeded or created has not yet made been clear to participants.  So, stay tuned... The course creators also created a game called "Vax" showing differences between vaccination strategies.

The epidemic is about half-way over, at least in terms of course time, and here are a few physical and online maps that I have produced using QGIS and CartoDB. The course instructors have released a basic *.text file of date/times and coordinates for crowd sourced analysis.  CartoDB allows for beautiful maps to be created quickly, has CartoCSS elements, but does not require the expertise and time as other packages such as MapBox/TileMill.

What I chose and why:  I chose to use QGIS as my desktop GIS platform.  In addition, I chose Natural Earth for my base layers.  Using both, I knew that any of my tens of thousands classmates could duplicate my work for no cost.  Furthermore, they maintain accuracy worldwide but keep details to a minimum, so I could work with them quickly.  I did not need to be bogged down with huge layers or downloads. 

The physical maps are below and a link to one interactive map with cases can be found here:  http://cdb.io/17C1sKA.  Click on the maps below to enlarge them.



Week 1 Map: Early in the epidemic...

 

Hong Kong: Generated/fake "cases" appear to be located in
 the water through error or perhaps how they are being generated.

 

 

Quantum GIS 2.0 Dufour Released

This entry is out-of-date.  Please read: http://opensourcegisblog.blogspot.com/2014/07/qgis-24-chugiak-released.html

Quantum GIS or QGIS 2.0 has been released!  Be sure to check it out on the newly redesigned QGIS website: http://www.qgis.org/en/site/.

New Sleek Looking QGIS Website

The user interface has undergone some improvements aesthetically and functionally.  Several of the plugins appear to be working better--including the heat map add-on--for getting your spatial analysis started. The user can even choose the type of kernel function.  Symbolizing layers also has improved and appears to be easier.

A Heat/Density Map of Healthy Food Stores in Philadelphia

 For a full list of the new features, go here: http://www.qgis.org/en/docs/user_manual/preamble/whats_new.html

If you have not used QGIS before, be sure to check out the user's section: http://www.qgis.org/en/site/forusers/index.html

Lastly a new e-book and book in print has been published by a top QGIS blogger.  Be sure to check it out, even if you have some experience using QGIS before! http://www.packtpub.com/learning-qgis-2-0-to-create-maps-and-perform-geoprocessing-tasks/book

Trivia: Previous releases of QGIS have been named after places.  However, this release is named after a famous cartographer: http://en.wikipedia.org/wiki/Guillaume-Henri_Dufour

Open data combined with open source GIS is an extremely powerful and versatile platform!

Cleaning Address Fields with R String Functions

I have been surprised by the lack of solutions for cleaning addresses in the open source world. So, I decided to look into R Statistical Program.  Whether in R or other statistical programs, both have string/character functions that allow for splitting fields.  The stringr R package is also very helpful.

Dirty address fields can be a symptom of problems with data collection (lack of defined fields, standardization, minor errors) or something simple--like  typographical errors -- which can be compounded over time. 

These mistakes can affect matching of addresses to reference datasets and ultimately any analysis that is performed. If addresses are so poorly collected, no analysis may actually be able to be done or simply have results that are two unreliable to interpret.

Before geocoding addresses, it is best to get the data as "clean" as possible.  If you have a database setup properly with data being entered by automation or by hand, validation rules, or warning messages about potential conflicts, then you should be in relatively good shape. 

Hopefully, in the coming weeks, I will have some sample data and R code posted illustrating common problems and solutions.

OpenLayers 3.0

OpenLayers is a great resource for those wanting to put a map on the web.  Simply put, OpenLayers "is a pure JavaScript library for displaying map data in most modern web browsers, with no server-side dependencies." Many posts ago, I used OpenLayers to post a web map.

New features will include a more accessible API and a host of other features.  An alpha version is currently available for download: https://github.com/openlayers/ol3/releases/tag/r3.0.0-alpha.4

If you have not seen OpenLayers libraries before be sure to check out: http://openlayers.org/.

AIDSVu Map Provides Better National View of the Epidemic

AIDSVu Map provides the "most detailed publicly available view of HIV prevalence in the United States"  It is a "compilation of interactive online maps that display HIV prevalence data at the national, state and local levels and by different demographics, including age, race and sex."

Estimates of the prevalence of persons living with HIV go from the state and county level down to ZIP codes and census tracts in the United States.  AIDSVu was produced by the Emory School of Public Health.  In addition, it provides aggregate data for download and use.  The website uses OpenStreetMap. Click either of the screenshots below to enlarge them.

An Overview of Several Cities



The Epidemic in Houston

In addition, the group does a good job explaining the methods for protecting patient privacy--avoiding cases where a person's identity may be surmised from sparse population, data, or a combination of circumstances.

However, it would be nice to see some spatial analysis doneor overlays with socioeconomic data to help the viewer understand patterns.  Overall, the map performs very well on the web.  Zooming-in is relatively straightforward and the map renders well--but is quite flicker-y.  Maybe a projection issue? It is good to see some agencies using census tracts over ZIP codes because of the ease to link them to Census and American Community Survey (ACS) Data.

USGS Seamless ArcGIS Toolbar

Paid and free and open-source software (FOSS) and data do not have to work in isolation.  One example is the USGS ArcGIS Toolbar (for versions 9.3 and 10) that allows users to seamlessly download data from the USGS into ArcGIS. 

As stated on the USGS website:
"The purpose of the enhanced tools are to allow the user to define an area of interest (AOI), select products or options for downloading products, and then download the product to a local disk. The capabilities available in ArcMap would allow for more client options: add preview, index and outline layers, template selection, reprojection, and import the downloaded products into the current map overlay. All of this can be done without leaving the ArcMap environment. With the functions included with the ArcGIS toolbox, users may allow for client-side scripting, model-building, and easier integration in local ArcGIS based development." 

It beats hopping from different websites, waiting and moving downloads, checking your e-mail, and all of those other activities preventing you from getting work done!

Check it out here and give it a try!:  http://cumulus.cr.usgs.gov/toolbar.php