Dramatic Before and After Images of Indian Ocean Tsunami… In a Slider

The 26 December 2004 Indian Ocean Tsunami killed more than 250,000 people in a single day. It is the most devastating tsunami in modern times. Two particularly striking satellite images show the devastation of the Banda Aceh coast, on the island of Sumatra, where the tsunami reached 6–12 m (19.7 ft-39.4 ft) and killed 167,000 people.

This Post is Really About Image Visualization Tools

You’ve probably seen many before/after photos of the 2004 Tsunami. I recently saw an image slider that caught my attention and thought worth a share. The following before/after images are displayed using Juxtapose Slider. Drag the center bar across to see the change:

About Juxtapose Slider

The slider is created using the free, open source, JuxtaposeJS. Its a handy tool that helps storytellers compare two pieces of similar media, including photos, and GIFs. It’s ideal for highlighting then/now or before/after stories that show the impact of single dramatic events. It was produced by the Northwestern University Knight Lab, created by Medill student Alex Duner.

JuxtaposeJS works on all devices. All you need to get started are links to the images you’d like to compare.

Install QGIS on a Mac in 8-Steps

**UPDATED FOR QGIS 2.16 – 07 Oct 2016**

QGIS is an impressively powerful open source geographic information system (GIS). In 2010, I reviewed QGIS when it had an “All-In-One” installation bundle for the Mac. That one-step installation has gone by the wayside, and while QGIS is an excellent GIS solution for Mac users, installation is much more of a chore. As a software developer myself, I can only imagine the installation process discourages use by the average consumer (and by average, I mean moderately sophisticated GIS users).

If you’re in that camp, this guide is for you… it provides (without warranty) a step-by-step guide to successfully install the supporting frameworks and the QGIS software. These instructions are for QGIS 2.16 built for Mac OS X Mountain Lion, Mavericks, Yosemite, El Capitan, and (hopefully) MacOS Sierra.

Installing QGIS on a Mac

Step One: Honesty

Installing most software on a Mac is easy, but installing QGIS on a Mac is a pain (though it is getting easier with each release!)¹. I’ve stumbled through it a couple of times now.

There are supporting frameworks that must be installed first, and in a particular order, before the QGIS installation can begin. If you try installing QGIS before installing the supporting frameworks, you’ll likely see an error message like this:

qGIS installation error

Also, always read the ReadMe files included with your downloads before installing. For example, this important ReadMe message is included with the QGIS Installer:

 If you have an old QGIS.app in your Applications folder, trash it before installing QGIS 2.16.
 Old files may not be deleted by the installer, which may cause problems for QGIS2.16

In summary, the following download is required:

  1. Download QGIS for Mac Installer. There is no need to download and install these frameworks individually if this package is installed. All required items are included on the disk image, which includes:
    • GDAL Complete.pkg (installs framework package)
    • NumPy.pkg (installs python module)
    • Matplotlib.pkg (instalsl python module)
    • Install QGIS.pkg (installs the app!)
The Real 10 8 Steps

STEP 1. To allow installation of non-Apple developer recognized software, first change your Mac Security Preferences to ‘Allow apps downloaded from: Anywhere’

STEP 2. Download the ‘QGIS for Mac’ installer

Download QGIS for Mac Installer. Double-click the ‘QGIS-2.6.1.dmg’ to view its contents:

qgis-2-16-installer

STEP 3. install GDAL Complete —  double-click the ‘GDAL Complete.pkg’ and step through its installation.

STEP 4. Install NumPy — double-click the ’NumPy.pkg’ and step through its installation.

 

STEP 5. Install Matplotlib —  double-click the ‘matplotlib.pkg’ and step through its installation.

 

STEP 6. Install QGIS —  double-click the ‘Install QGIS.pkg’ and step through its installation.

STEP 7. Proceed to your Applications folder and find the QGIS app. Double-click to launch.

Be patient, it took a little less than a minute on first launch for my copy of QGIS to fully open. Also, even if you are familiar with GIS software, don’t expect QGIS to be completely intuitive. Like any new app, you need to take the time to learn its features and user interface. Fortunately, there are some terrific learning resources available, like the QGIS Tutorials and Tips by Ujaval Gandhi and the QGIS User Guide.

You now have a sophisticated GIS software to learn and enjoy. Depending on your needs, you might even want to add some of the QGIS Plugins.

STEP 8. Your almost done! To finish things off you should do the following:

a. Change your Mac Security Preferences back to ‘Allow apps downloaded from: Mac App Store and Identified Developers’ (or Mac App Store only).
b. Save the QGIS.dmg files, since they each contain uninstall instructions should you ever need them.

 

¹ Software isn’t always easy. I really appreciate the great work of good folks who support this open source (and free) software. The main release packages for QGIS for Mac are maintained by Kyngchaos, aka William Kyngsburye. (thank you!)

Install QGIS on a Mac in 10-Steps

**NEW: VIEW THE UPDATED STEPS FOR QGIS 2.16 – 07 Oct 2016**

The following instructions were for QGIS 2.10 and are kept here for historical record:

QGIS is an impressively powerful open source geographic information system (GIS). In 2010, I reviewed QGIS when it had an “All-In-One” installation bundle for the Mac. That easy installation has gone by the wayside, and while I still find QGIS an excellent GIS solution for Mac users, installation is much more of a chore. As a software developer myself, I can only imagine the installation process discourages use by the average consumer (and by average, I mean moderately sophisticated GIS users).

If you’re in that camp, this guide is for you… it provides (without warranty) a step-by-step guide to successfully install the supporting frameworks and the QGIS software (these instructions are for QGIS 2.10 built for Mac OS X Lion, Mountain Lion, Mavericks and Yosemite, though presumably will work with more current updates as they are added).

Installing QGIS on a Mac

Step One: Honesty

Installing most software on a Mac is easy, but installing QGIS on a Mac is a pain¹. I’ve stumbled through it a couple of times now.

There are supporting frameworks that must be installed first, and in a particular order, before the QGIS installation can begin. If you try installing QGIS before installing the supporting frameworks, you’ll likely see an error message like this:

qGIS installation error

Also, always read the ReadMe files included with your downloads before installing. For example, this important ReadMe message is included with the QGIS Installer:

 If you have an old QGIS.app in your Applications folder, trash it before installing QGIS.
 Old files may not be deleted by the installer, which may cause problems for QGIS.

In summary, the following downloads are required:

  1. Download GDAL Complete 1.11 framework package, which includes:
    • GDAL Complete.pkg (install framework package)
    • NumPy.pkg (install python module)
  2. Download Matplotlib Python module, which includes:
    • Matplotlib.pkg (install python module)
  3. Download QGIS for Mac Installer, which includes:
    • Install QGIS.pkg (install the app!)

 

The Real 10 Steps

STEP 1. To allow installation of non-Apple developer recognized software, first change your Mac Security Preferences to ‘Allow apps downloaded from: Anywhere’

STEP 2. Download the ‘GDAL 1.11 Complete’ framework package

Download ‘GDAL 1.11 Complete’ from http://www.kyngchaos.com/software/frameworks#gdal_complete (1.11 is the current version at the time I wrote this article — there may be newer version).

This is actually a package containing several frameworks more conveniently packaged together in one installer. Importantly, the required ‘GDAL Complete.pkg’ and ‘numPy.pkg’ are both included in the ‘GDAL 1.11 Complete’ download.

Double-click the ‘GDAL_Complete_1.11.dmg’ to view its contents:

STEP 3. install GDAL Complete —  double-click the ‘GDAL Complete.pkg’ and step through its installation.

STEP 4. Install NumPy — double-click the ’NumPy.pkg’ and step through its installation.

STEP 5. Download the ‘Matplotlib’ python module from http://www.kyngchaos.com/software/python

Double-click the ‘matplotlib-1.3.1-2.dmg’ to view its contents:

STEP 6. Install Matplotlib —  double-click the ‘matplotlib.pkg’ and step through its installation.

STEP 7. Download QGIS Mac OS X Installer from http://www.kyngchaos.com/software/qgis

Double-click the ‘QGIS-2.10.1-1.dmg’ to view its contents:

 

STEP 8. install QGIS —  double-click the ‘Install QGIS.pkg’ and step through its installation.

STEP 9. Proceed to your Applications folder and find the QGIS app. Double-click to launch.

Be patient, it took a little less than a minute on first launch for my copy of QGIS to fully open. Also, even if you are familiar with GIS software, don’t expect QGIS to be completely intuitive. Like any new app, you need to take the time to learn its features and user interface. Fortunately, there are some terrific learning resources available, like the QGIS Tutorials and Tips by Ujaval Gandhi and the QGIS User Guide.

You now have a sophisticated GIS software to learn and enjoy. Depending on your needs, you might even want to add some of the QGIS Plugins.

STEP 10. Your almost done! To finish things off you should do the following:

a. Change your Mac Security Preferences back to ‘Allow apps downloaded from: Mac App Store and Identified Developers’ (or Mac App Store only).
b. Save the three downloaded .dmg files, since they each contain uninstall instructions should you even need them.

 

¹ Software isn’t always easy. I appreciate the great work of good folks who support this open source (and free) software. The main release packages for QGIS for Mac are maintained by Kyngchaos, aka William Kyngsburye. (thank you!)

Maps In Modern Web Design: Showcase and Examples from Smashing Magazine

In a world where digital mapping is exploding, Zach Dunn offers an excellent review of different types of web maps and their various purposes.

His article, Maps In Modern Web Design: Showcase and Examples (Smashing Magazine) explores existing trends, conventions and the possible future of interactive maps online.

This isn’t a lesson in cartography, rather a review of the important purposes that maps can serve in modern web design. Three main areas seem to represent the majority of tasks:

  1. Navigation and directions,
  2. Show relationships and trends geographically,
  3. Show points of interest.

Geared primarily toward a web-designer audience, this article is good review for GIS specialists and cartographers preparing maps for online content. Zach describes the different ways to navigate online maps (drill down for information, timeline, zoom, before-and-after, and points of interest), looks at future trends, and provides a nice showcase of maps for inspiration.

Quantum GIS (qGIS) for the Mac

UPDATE:

As of QGIS v. 1.5 (2010) the stand-alone ‘all in one’ bundle for Mac OS X is no longer supported. Installation requires dependent frameworks, each with their own requirements, to be installed in order before the installation of QGIS.

UPDATE

Here are revised (2015) instructions for installing QGIS on a Mac

A while back I reviewed MyWorldGIS, indicating my disappointment with the analysis capabilities of other available free or low-cost GIS for the Mac. Well, no longer. Since its birth in 2002, Quantum GIS (qGIS) has grown to be an impressively powerful application in its own right.

qGIS is an Open Source Geographic Information System (GIS) licensed under the GNU General Public License. QGIS is an official project of the Open Source Geospatial Foundation (OSGeo) and is a volunteer driven project. It runs on Linux, Unix, Mac OSX, and Windows and supports numerous vector, raster, and database formats and functionalities. In this review I’ve chosen to highlight its Mac-ness, both because I am a Mac user and I am often asked about Mac GIS options.

Over its life-cycle, qGIS has dished out a continously growing number of capabilities provided by core functions and plugins – and appears to be still growing strong. You can visualize, manage, edit, analyze data, and compose printable maps. Best of all (in my opinion) is a robust set of vector data analysis, geoprocessing, geometry, and data management tools and functionality now available. Sometimes open-source software gets a bad wrap for being too complicated, particularly in the graphical user interface (GUI) department. It is what it is – made by techies for techies, qGIS is a growing powerhouse of geospatial tools, though it might not win GUI awards for simplicity. Did I mention it is also free?

Overview of qGIS Features

First let’s get acquainted. A summary of features include:

  1. View and overlay vector and raster data in different formats (including GIS shapefiles) and projections without conversion to an internal or common format.
  2. Create maps and interactively explore spatial data, including on the fly projection, spatial bookmarks, identify/select features, feature labeling, change vector and raster symbology, and more.

  3. Create, edit and export spatial data, including GPS tools to import and export GPX format, convert other GPS formats to GPX, or down/upload directly to a GPS unit.

  4. Perform spatial analysis using the fTools plugin for Shapefiles.

  5. Publish your map on the internet using the export to Mapfile capability (requires a webserver with UMN MapServer installed)

These Are a Few of My Favorite Things

As a disclaimer, I typically use qGIS to explore shapefile data, manipulate data, and save selections of shapefiles to prepare them for import into our Ortelius cartography software (to which I am affiliated). My review is clearly influenced by these uses and by the questions we get from our own users wanting to do more with GIS.

qGIS Stand-Alone Installation

On the downside (or upside – depending on your point of view), there are a lot of download options. First, there are separate downloads for each operating system. Each also has a variety of dependancy frameworks with their own requirements. The standalone Qgis does not include GRASS support at all, if you want it you must use the standard Qgis package + frameworks + GRASS if you need GRASS features (GRASS is a GIS used for geospatial data management and analysis, image processing, graphics/map production, spatial modelling, and visualization – it is not required for qGIS though can provide added functionality). Wowza. This might leave many potential casual users puzzled before they even have the software!

Have no fear – a stand-alone installation ‘all in one’ bundle for Mac OS X is provided for “new users.” In fact, I highly recommend it for all but very technically-minded and advanced users.

Analysis With fTools qGIS Plugin

Do you need to count the points of one layer in polygons of another layer? Select by location? Buffer or intersect features? Convert feature geometry?Join attributes with an external table? Or more? If so, you definitely need analysis tools. Choose Plugins > Manage Plugins… from the main menu and enable the fTools plugin for data management and analysis. Doing so will add “Vector” to the main menu and provide a variety of tools for manipulating your vector GIS data.

I am often asked about software to join external spreadsheet data with GIS data. To do this, you need a common data field, such as country name, in both data sets. Choose Vector > Data Management Tools > Join Attributes from the main menu to identify your target GIS layer, join field, and database file to join. Note that you cannot directly link to Pages® or Excel® spreadsheets, rather you must link to a DBF file. This is especially a pain since Excel (Mac 2008) stopped having a DBF export option. I have turned to using open-source software NeoOffice to convert my spreadsheet data to DBF to prepare for linking attribute tables. It is an inconvenient step, so if you have a better solution for Mac users, please share! Once you’re done, the automatic save of the output shapefile makes things especially easy.

X,Y Data to Shapefile

Lots of people have X,Y coordinate data (e.g., latitude/longitude data) in spreadsheet format that they want to display on a map. In fact, if you have a simple address list, you can use a service such as BatchGeocode.com to generate your X,Y data for you, then use the results to create shapefiles in qGIS. First choose Plugins > Manage Plugins… from the main menu and enable the Add Delimited Text Layer plugin. In the main menu, the Plugins menu will now list “Delimited Text” among its options. Use the GUI to import your tab delimited X,Y data.

Vector Editing

qGIS supports editing the points, lines and polygons of shapefile map data. Choose Layer > Toggle Editing to activate the editing toolbar. qGIS has a suite of editing tools to cut and add features.

Save Selection as Shapefile

Perhaps I use this most – I simply love the ease of which you can select features in a layer and save them as a new shapefile. Use the Select Features tool from the toolbar to directly select features on your map, or open Attribute Table and select features from the table view. Then, simply choose Layer > Save Selection As Shapefile form the main menu. It’s as easy as that and a powerful tool when pairing down large shapefiles to your area of interest.

Conclusion

While there are a plethora other features that could be mentioned, these are among the ones I use the most. On the down-side, the cartographic rendering in qGIS is typical of a low- to mid-range GIS programs (unfortunately which can easily produce ugly GIS-looking maps). Although packed with features, the program can be overwhelming for new users who are just getting started with GIS. If you are in that lot, the provided Users Manuals are required reading. I find the GUI a bit cluttered with buttons, such as the five different buttons for importing a layer when one might suffice. Organization in the GUI might also be improved by consistently locating active plugins – either by adding active plugins to the Plugin menu or as separate menu items, but not both – it can  be confusing when you activate a plugin and it isn’t where you expect it to be.

Overall, qGIS is a strong performer with a dedicated volunteer development base. Kudos to the development team for continuing development on this much needed application. It gets high marks in analysis and data management and I recommend it for Mac GIS users.

There are unlimited uses of GIS software in general, and qGIS specifically, that I haven’t covered. Do you have experience with qGIS you’d like to share? Do you have experience with other GIS for Mac tools? If so, I’d love to hear from you.