Category Archives: Analysis

Visualizing an Intervention for Tobacco Control

Submitted by Jennifer Rewolinski

Dr. Heckman, an assistant professor of psychiatry and behavioral sciences at the Medical University of South Carolina (MUSC) in Charleston, used Community Health Maps (CHM) tools in his research on tobacco control. Smoking is the leading preventable cause of death worldwide and costs the US $130 billion in direct medical costs annually. Smoking is still a major public health issue that influences mortality, morbidity, healthcare costs, the environment, and quality of life.

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Dr. Bryan Heckman

The outcome of Dr. Heckman’s precision medicine project will be a mobile app that aids smokers who recently quit by alerting them of proximity to stores which sell cigarettes or alternative nicotine products. Studies show that greater tobacco retailer density is associated with greater incidence of relapse; Dr. Heckman believes that mapping provides a new approach to visualizing environmental factors. A CHM training event at MUSC spurred his decision to integrate mapping into his own work using the CHM labs as a guide. These labs provide step-by-step instructions for implementing the CHM workflow. He used the data collection app Fulcrum on an iPhone to collect information on retailers: GPS coordinates, type, type of tobacco products sold, e-cigarette advertising, and photos. His team also used a high-powered Trimble GPS device to test accuracy of phone GPS, and the accuracy of phone GPS was adequate and more cost effective than more expensive GPS devices.

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Figure 1. Dr. Heckman’s in progress map shows higher numbers of tobacco retailers are associated with  Census Tracts that have both higher poverty and a higher percentage of minority populations.

Dr. Heckman integrated his Fulcrum data into QGIS software. He added national datasets from the American Community Survey and Behavior Risk Factor Surveillance System for Census tract data, and Synar for retailer data to check the validity of the Fulcrum data; field data collection with Fulcrum revealed a more accurate list of current retailers than the national secondary datasets provided. Dr. Heckman believes QGIS is a powerful tool with many features; he was not only able to use QGIS to monitor and visualize his research questions but also to guide his project decisions and hypotheses. His results will guide policy recommendations, improve access to care, and deliver novel interventions.

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Figure 2. Dr. Heckman’s in progress map shows higher numbers of tobacco retailers are associated with Census Tracts with higher percentages of minority populations.

For those attempting to undertake a health GIS project on their own, Dr. Heckman emphasized that all the tools needed are provided on the CHM blog; only time and patience are required. He also recommends asking for help and reaching out to other CHM users who have experience. Dr. Heckman’s project has the potential to affect behavior change and reduce health disparities via a mobile intervention app which identifies nearby tobacco retailers and prompts and provides an intervention and awareness of a health issue. Dr. Heckman’s experience is an example of how the CHM blog and tools might be used.

Dr. Heckman would like to thank Kurt Menke and the CHM team, Dr. Williamson from MUSC, and his mentors for inspiration and growth. He would also like to acknowledge the Hollings Cancer Center and American Cancer Society Institutional Research Grant that helps support his work, and Alex Hirsch for his help coordinating the project.

The CHM team would like to extend their own gratitude to Dr. Heckman as they sincerely appreciate his time and his support of the CHM blog.

Mapping Curb Ramp Accessibility around a Silver Spring, MD Assisted Living Facility

Submitted by Jenny Rewolinski, University of Maryland, B.S. Community Health 2016

I just completed a spring internship with the National Library of Medicine (NLM). My goal was to demonstrate what a typical user of the Community Health Maps (CHM) blog might experience, while using the low cost resources it reviews to develop a mapping project with a public health focus. I read through the case studies on the CHM blog and used its labs to develop my project plan and to guide my related decisions.

Because of my experience with elderly relatives and my background in public health, I centered my project on how the senior population of a nearby Assisted Living Facility might safely navigate local sidewalks. According to the 2014 American Community Survey, 23% of people over 65 have some sort ambulatory disability. With this in mind, I decided to map local curb ramps –sloped transitions between sidewalks and streets which function as accessibility enhancements to help those with mobility issues to cross streets safely.

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Figure 1. Curb Ramp Data Collection using the iForm app

I used CHM Lab 1: Field Data Collection to learn how to design my own data collection form using iForm. My Curb Ramp form captured curb ramp location, conditions, and other observations such as seniors using the curb ramps, steep or damaged curb ramps, and a lack of sidewalks in the area. As discussed in a prior blog post, How Accurate is the GPS on my Smart Phone?, phone geolocation is usually accurate up to 8 meters. This was not precise enough for my curb ramp data, so I corrected for this on my form.  Over the course of 8 hours spanning 2 days, and with 2 other interns I collected 103 existing curb ramps and locations where curb ramps might aid accessibility.

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Figure 2. iForm Curb Ramp Data Collection Form

Next, I brought my iForm curb ramp data from my phone into the QGIS software by using instructions from CHM Lab 2: Bringing Field Data into QGIS.  I also used CHM Labs 3: Combining Field Data with Other Organizational Data and CHM Lab 4: Basic Spatial Analysis  to add data layers and to perform spatial analysis to finalize my map.

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Figure 3. Curb Ramp Accessibility of Senior Population of Silver Spring Assisted Living Center Map

This is my project map! I completed construction of my map using CHM Lab 5: Cartography with QGIS. In addition to my curb ramp data points, I added data layers for sidewalks, roads, places of interest (such as grocery stores, restaurants, bus stops,  theaters), and my Assisted Living Facility. My goal was to raise awareness of how accessibility can impact seniors’ sense of autonomy and empowerment, and their ability to exercise and to lead a healthier lifestyle. This map also provides recommendations for where more curb ramps should be placed based on observations during data collection. I plan to discuss this map and curb ramp recommendations with the city of Silver Spring and to create “safest route” guides for popular local destinations.

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Figure 4. A Safest Route Guide example showing safe and dangerous routes based on location of curb ramps and sidewalks

GIS has a huge potential to help us analyze health issues. When I began my project at NLM, I thought I would simply be mapping the location of curb ramps near a local Assisted Living Facility; however I discovered the significant need for more curb ramps as well as sidewalks around my project area.

I believe the conclusions I was able to reach by using the low cost CHM resources CHM are accurate and workable. I came to NLM with little to no GIS knowledge yet I learned from the CHM GIS labs, collected curb ramp data points and created a map that may bring awareness to a public health issue. In doing so I believe my experience is typical of many CHM users.

If I can do it, you can too!

A New Version of QGIS v2.14 Has Been Released!

Currently a new version of QGIS is released every four months!  To help users deal with this rapid development pace, the version put out each spring is designated as a long-term release (LTR). This means it will be supported for one calendar year. After that, new stable versions continue to be posted quarterly and any bug fixes associated with those quarterly versions are applied to the LTR. The LTR is recommended for production environments. It has a slower release cycle, and receives regular bug fixes throughout the year. Monday February 29th QGIS 2.14, the next LTR was released. It is nicknamed ‘Essen’ after the town in Germany where a recent developer meeting was held.

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QGIS Essen

Essen has a lot of new features. You can visit the Visual Changelog to read about all the new features in detail. You can also see who developed and sponsored each new feature. Community Health Mappers might be especially interested in these new features:

  • the new 2.5 D renderer which allows you to extrude features into space.
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Example of 2.5 D Rendering by Nicholas Duggan @ XYHT.com

  • improved labeling
  • better control over map elements in the Print Composer
  • an improved Processing Toolbox
  • the new widget you get by right clicking on a layer in the Layers Panel and choosing Style. It allows you to change the color for a symbol without having to open a single dialog box!
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Style Widget

If you are using QGIS you should visit the download page and install the latest version! Note that the Mac installer takes a little longer to assemble and may not be available for several more days.

Happy GIS’ing!

Community Health Mapping: A New Year Review

To start the New Year I thought I’d begin with a review of Community Health Mapping (CHM). There are a lot of new project partners, and I thought it would be a good time to give a project overview. CHM is a collaborative effort between the National Library of MedicineCenter for Public Service Communications and Bird’s Eye View. The National Library of Medicine is funding the initiative.

The overall goal is to empower community organizations serving vulnerable or underserved populations with low cost, intuitive mapping technology. Therefore we’ve been working with programs organizations who:

  • Focus on vulnerable populations
  • Frequently use and collect data
  • Need effective, scalable & easy to use mapping tools
  • Lack resources (i.e., for proprietary GIS training & software)

We have identified a suite of tools that allow you to collect custom field data, analyze that data, combine it with other spatial datasets, and generate both static maps and/or dynamic maps on the internet. This allows organizations to collect and work with their own data, and if appropriate, share it with others. CHM involves three components that meet all basic mapping needs:

  • Field Data Collection
  • Desktop Analysis and Cartography
  • Internet Mapping
Community Health Mapping Workflow

Community Health Mapping Workflow

A given project may not require all three, however, collectively these components address the basic needs of all mapping projects.

Field Data Collection:

Rather than focusing on the use of expensive GPS receivers, we recommend the use of smart phones and tablets for these reasons:

  • Most community-based organizations already have them!
  • Many know how to use them
  • They’re intuitive
  • They’re portable
  • They come with an on board GPS receiver (iPhone 5 uses GPS + GLONASS)
  • Have on board cameras
  • Can connect to wireless networks
  • Access to the internet
  • Email is available
  • “There’s an app for that!”
SmartPhones and Tablets vs. Traditional GPS Receivers

SmartPhones and Tablets vs. Traditional GPS Receivers

Of course an important consideration is horizontal accuracy. You can read our blog post on that topic to see if mobile smart devices meet your project needs.

When collecting data you need to be able to develop your own custom data collection form. The top three mobile apps we have found are:

Desktop Analysis and Cartography:

After community field data collection, the next step typically involves bringing the data into a desktop GIS. This is the middle step in the workflow. Here the data can be viewed against basemaps such as Google or OpenStreetMap, and combined with other organizational data. This is also where analyses (proximity, density etc.) can be conducted. Presentation quality maps can also be generated in this step.

The software we found to be the best fit is QGIS. This is an open source desktop GIS software. It has many strengths:

  • It can consume many kinds of data, including all the data that would come out of the field data collection apps.
  • It is both intuitive and robust.
  • It has a large suite of geoprocessing tools for analyzing data.
  • It will run on Windows, Mac, or Linux.
  • It is free to download and install.
  • It is well documented.
  • There is a large user community.
  • New functionality is being continuously added. New stable versions are being released every 4 months!
Baltimore Diabetes Data in QGIS Desktop

Baltimore Diabetes Data in QGIS Desktop

Web Presentation

Often you may want to present an interactive map of your results. Interactive means the map reader can zoom in/out, pan the map and turn layers off and on. For this we recommend CartoDB.

You can sign up for a free account, which gives you 50Mb of storage space. Data can be collected with a smart phone or tablet and brought directly into CartoDB.  It is a very intuitive platform. You can literally drag and drop a spreadsheet onto the CartoDB page and have the data upload to your account.  It will accept the most common geospatial file formats including: spreadsheets and comma delimited text files with addresses or coordinates, KML/KMZ, GPX, and shapefiles.

CartoDB also has great documentation including:

Baltimore Diabetes Data in CartoDB

Baltimore Diabetes Data in CartoDB

In Conclusion

This blog has a lot of resources including reviews of mapping technology and case studies. You might begin by clicking on some of the links in this entry. We are also working on a 6 lab CHM curriculum that interested parties will be able to use to hone their skills. Stay tuned for that!

We are always looking for new partners and continuously work to support current project partners. If you are interested, or have questions please don’t hesitate to contact John Scott (jscott at cpsc.com) or Kurt Menke (kurt at birdseyeviewgis.com). Most importantly get out and do some mapping in 2016!

 

 

 

Map and Analyze Field Data with QGIS

After community field data collection, the next step typically involves bringing the data into a desktop GIS. This is the middle step in the workflow outlined in the Introduction. Here the data can be viewed against basemaps such as Google or OpenStreetMap, and combined with other organizational data. This is where analyses can be conducted. Presentation quality maps can also be generated in this step.

The software we found to be the best fit is QGIS. This is an open source desktop GIS software. It has many strengths:

  • It can consume many kinds of data, including all the data that would come out of the field data collection apps.
  • It is both intuitive and robust.
  • It has a large suite of geoprocessing tools for analyzing data.
  • It will run on Windows, Mac, or Linux.
  • It is free to download and install.
  • It is well documented.
  • There is a large user community.
  • New functionality is being continuously added. New stable versions are being released every 4 months!

 QGIS Browser:

QGIS has two main applications: QGIS Browser and QGIS Desktop. Browser allows you to preview your GIS data. It is similar to Windows Explorer, or Mac Finder, but is designed to work with GIS data. It has a File Tree, a main Display Window, Database Connections and Display Tabs (See figure below). It allows you to view basic information about a GIS layer and preview both the spatial features and the attributes. Data can be dragged and dropped from QGIS Browser to QGIS Desktop.

QGIS Browser

QGIS Browser

QGIS Desktop:

Desktop is the program for conducting analyses and making maps. It comes with tools for editing and manipulating GIS data. The main interface is similar to well known proprietary GIS packages with a Table of Contents along the left side. This shows your data layers and the symbol applied to them. The majority of the space is taken up with the Map Window (See figure below). Buttons along the left side allow you to add data to a map. Buttons along the top allow you to pan and zoom into the map. There are additional editing and data analysis tools available from menus.

QGIS Desktop

QGIS Desktop

With QGIS Desktop you can perform analyses such as calculating distances to resources, characterizing communities with socioeconomic data from the U.S. Census (NOTE: you will need to obtain data from the U.S. Census to do this), or generate new data like density surfaces.  The sky is the limit.

QGIS Desktop also comes with a Print Composer (See figure below). This opens in a separate window and allows you to craft a publication quality map. Common map elements such as a title, legend, scale bar, north arrow, logos, and text can be added. The final map can be exported in a variety of common image formats such as: jpg, png or tif. Maps can also be exported as pdf’s. If you want to do additional design work in a program like InkScape or Adobe Illustrator the maps can also be exported as svg files.

QGIS Print Composer

QGIS Print Composer

Resources:

While fairly intuitive, GIS work can still be rather complicated and full of jargon. There is a learning curve involved. To help with this we have resources that explain how to install QGIS and bring in data from the three recommended field data collection apps.

For more complete GIS training with QGIS there is the newly created FOSS4G Academy. This is a five course curriculum teaching GIS principles via QGIS. The material is available for free here: http://foss4geo.org/. The courses include:

  • GST 101 – Introduction to Geospatial Technology
  • GST 102 – Spatial Analysis
  • GST 103 – Data Acquisition and Management
  • GST 104 – Cartography
  • GST 105 – Remote Sensing

QGIS also comes with thorough documentation.

Download it today and try it out!