Webinar 16
San Antonio – Bexar County Metropolitan Planning Organization’s (MPO) Interactive Mapping Application (iMap)

October 2, 2018

Summary of the Federal Highway Administration’s Quarterly Webinar: Applications of Geospatial Technologies in Transportation

These notes provide a summary of the PowerPoint presentation discussed during the webinar and detail the question and answer sessions that followed the presentation.

The presentation is available upon request from the webinar speakers, Cecilio Martinez (martinez@sametroplan.org) and Clayton Elkins (elkins@sametroplan.org).

The webinar recording is available at: https://connectdot.connectsolutions.com/p1k1ktd9nc2/.


Cecilio Martinez
Senior Geographic Information Systems (GIS) and Web Analyst
San Antonio-Bexar County Metropolitan Planning Organization (MPO)

Clayton Elkins
GIS Analyst
San Antonio-Bexar County MPO


Approximately 61 participants attended the webinar.

Introduction to Presentation

Mark Sarmiento of FHWA thanked participants for joining the webinar. This webinar was the sixteenth in a quarterly series of FHWA-sponsored webinars. The series deals with the application of geographic information systems (GIS) and other geospatial technologies to transportation. This webinar focused on the San Antonio-Bexar County MPO's iMap application, a publicly available online mapping tool that allows for easy access to MPO data as well as citizen input into the planning process.


Cecilio Martinez, Senior GIS and Web Analyst for the San Antonio-Bexar County MPO, provided an overview of the MPO's responsibilities as well as the data layers and tools available in iMap.

San Antonio-Bexar County MPO Background

The San Antonio-Bexar County MPO addresses the urban transportation needs of the greater San Antonio, Texas, metropolitan area. In addition to San Antonio, the seventh-largest city in the country, the MPO's study area includes all of Bexar County and parts of Comal and Guadalupe County, encompassing 1.8 million citizens. In addition to working with the City of San Antonio and the County of Bexar, the MPO works closely with the Alamo Area Council of Governments, the Greater Bexar County Council of Cities, the Northeast Partnership for Economic Development, the Texas Department of Transportation (TxDOT), and VIA Metropolitan Transit.

The MPO's primary programs and plans include the two-year Unified Planning Work Program, the 25-year Metropolitan Transportation plan, and the Transportation Improvement Program, which documents funded transportation projects over a four-year timeframe. The MPO's responsibilities under these plans and programs include planning for bicycle and pedestrian use, mapping, air quality analysis and conformity, forecasting future problems through travel demand modeling, safety improvements, and collecting input from citizens through formal public involvement processes.


The MPO developed iMap to make the agency's data available in a single web-based application. iMap includes data on short- and long-term roadway projects, functionally classified roadways, bicycle and walking infrastructure, projected congestion levels, and crashes. iMap also incorporates crash data and traffic counts from TxDOT, route and stop information from VIA Metropolitan Transit, and natural resources from the Edwards Aquifer Authority, as well as political boundaries and physical facilities (e.g., fire and police stations, libraries, schools, universities, parks, military bases). iMap includes a total of 64 data layers.


iMap includes a legend and table of contents that allows users to understand the application's symbology and activate and deactivate layers. iMap's identify and search tools allow users to find detailed information about data layers, while an address locator and bookmarks enable easy access to specific areas of a map. iMap also allows users to make measurements on a map. Google Street View and Bing Maps imagery are also available, as are feeds from TxDOT's TransGuide traffic cameras.

iMap users are able to print maps or export data to GIS or Computer-Aided Design (CAD) programs. Users can also create heat maps based on crash frequencies or crash types. The MPO also uses iMap to collect input and feedback from citizens on planned projects.


iMap supports increased productivity and efficiency in fulfilling requests for data and information. Instead of responding directly to requests from the public or planning staff, the MPO can send users to iMap to view and download available GIS layers. iMap also consolidates many data layers in one place. In addition to the layers available directly in iMap, users can import new data layers. Finally, iMap allows the MPO to interactively collect feedback from the public.

General Demonstration

Clayton Elkins offered a demonstration of iMap. The iMap icon on the right side of the MPO's homepage launches an Adobe Flash-based application, first displaying a disclaimer stating that the data in iMap are not intended to be survey-grade and that the MPO is not responsible for errors. The iMap interface operates similarly to Google Maps and Google Earth, with pan and zoom functions. At any point, a user can choose to view the map's full extent. Different base maps are available, including streets, aerial photography provided by ESRI, topography, or a hybrid provided by Bing.

A floating window displays the available layers in iMap, collapsed into categories. Mr. Elkins provided an example of how iMap can perform a crash rate analysis, which requires crash frequency, roadway length, and traffic count data. Selecting the crash data layer displays all crashes on the map that occurred in the selected year. The graphical search tool can help draw a polygon around the area of interest to count the number of crashes. A user can then measure the length of the road segment using the straight line measurement tool. Finally, a user can turn on a traffic count layer to determine traffic volumes on the target segment. These three pieces of information can be plugged into a formula to determine the crash rate. As a supplement to this analysis, iMap can create a heat map using the crash information in an area. If the heat map reveals a particular area of interest, an iMap user can investigate the location using the street view widget, which loads Google Street View and Bing oblique view imagery.

Mr. Elkins also demonstrated how to use iMap to research planned projects within a political region. iMap includes City Council District boundaries and project locations. A user can import additional data to analyze the impact of these projects on particular demographic groups.

Citizen Participation

In addition to providing data to the public and partners, the San Antonio-Bexar County MPO also uses iMap to encourage citizen participation. For example, the MPO conducts walkable community workshops in which agency staff meet with neighborhood associations to identify where pedestrian and bicycle infrastructure should be developed. Traditionally, these workshops used hard-copy maps on which citizens wrote their comments. With iMap, citizens can edit GIS data over the internet, indicating where bicycle and pedestrian infrastructure is needed and commenting on suggested improvements.

Demonstration for Citizen Participation

Mr. Elkins demonstrated the citizen input function of iMap. The interface is similar to the full version of iMap, but layers are automatically activated to display similar information as the hard-copy maps used in the in-person workshops. The map displays where sidewalks and bicycle infrastructure is available, as well as other data related to biking and walking. Using iMap, citizens can identify concerns in their neighborhood and leave a description on the map. Citizens can also draw where bike or pedestrian accommodations are needed. Users must initial each suggestion so that the MPO can track how many people use the application (since some users submit multiple suggestions). The MPO combines the results from iMap and its in-person workshops into a final report for each neighborhood.

Question and Answer Session

How much functionality is built in and how much was customized?
iMap was developed using ArcGIS Viewer for Flex (based on ArcGIS API for Flex), which was easy to use and can be downloaded from the ESRI website. It includes instructions on how to assemble all of the data. Many of the features come “out of the box” and do not require familiarity with coding. Especially with the new interface of Adobe Flex 3.0, applications are available to easily add layers and widgets.

Does the application work on smart phones?
It works with tablets, but not as efficiently with smart phones.

How do you incorporate the input of user comments into iMap at the walkable community workshops?
A link to the citizen input tool is provided to the hosting neighborhood association to post on their website so that citizens can provide input from their personal computer. Several laptops are also available at the in-person workshop for attendees to use.

Was the application developed in-house or by ESRI or another firm?
It was developed in-house using an open-source application (ArcGIS API for Flex) available at https://www.esri.com/en-us/arcgis/products/app-builders/overview.

Why the name iMap?
It stands for Interactive Mapping Application.

How often do you update the data layers?
We update as soon as our partner agencies or MPO staff provide updated data.

Can users identify features and attributes using hyperlinks on map features?
iMap does not currently have that functionality, but it is possible to add this functionality. One of the benefits of ArcGIS Viewer for Flex is that users can develop open-source widgets that can later be added.

Did TxDOT limit public access to crash data?
Yes, sensitive information has been removed from the crash data. TxDOT reviewed iMap and is comfortable with the data it contains.

You mentioned how you used the Flash API to develop iMap. Did you consider JavaScript?
In the beginning, we looked at three applications: JavaScript, Silverlight, and ArcGIS Viewer for Flex. At the time, JavaScript was not comparable to the other two options. It has caught up but we needed to pick an option and make it work right. iMap currently uses an older version of the ArcGIS Viewer for Flex (2.20), but there is now a newer version (3.0) which makes it easier to develop applications.

What is the most common way the public uses iMap?
The public tends to use iMap the most for bike facility information.

Do you perform any “data cleaning” prior to adding data to iMap?
Most of the time, we look at the data and strip away any information that might confuse users.

Can data be extracted to Bentley Microstation?
Yes, Microstation is an option in the export feature, along with a GIS shapefile, geodatabase, or CAD file.

Is it possible to export or print a portable document format (PDF) file with the data legend?
We recently upgraded to ArcGIS Sever 10.1. Prior to the upgrade, it was possible to print the legend, but since the upgrade, users have lost that ability. ArcGIS Server 10.1 offers a print service that will allow users to incorporate a legend into a PDF file and we are working to migrate that functionality.

Do you know how much traffic iMap attracts?
Based on Google Analytics, iMap receives an average of ten users per day, but that has increased since we have been advertising it more. Recently, iMap has experienced as many as 100 hits in one day.

Were there additional costs involved in developing iMap, besides in-house staff time?
The only additional cost to publishing your own information and data layers involves installing ArcGIS server. The price for that varies depending on the organization. iMap uses ArcGIS for Server Workgroup Advanced, which has less functionality and capabilities than the Enterprise version.

How do you handle tech support for public users? How much time does that entail?
We created a video that demonstrates how to use iMap. We received some calls from planners asking how to use some features, but once they understand how to use it, they typically do not call back. iMap is simple to use.

Is it possible to restrict access to data layers depending on their sensitivity?
It is possible, but iMap does not currently contain any sensitive data layers.

How long has iMap been available
Almost two years.

Do members of the public need an account to access iMap?
No, the public can access iMap directly through www.sametroplan.org (Website no longer available). The host organization has to register for a free account with ESRI to download the software.

Do the data reside in the cloud or on a local server?
The information is stored on a local server but it is possible to incorporate services from a cloud-based server. Currently, iMap resides entirely on a local server. In the future, we may investigate moving it to a cloud-based server but we cannot justify that now.

Are the local data served dynamically or as cached services?
The base layers from ESRI are cached. The other layers are served dynamically.

Have there been any issues with access or speed for multiple users?
Not that we have experienced.

How has your management reacted to iMap?
They love it and think it is one of the best products that the GIS employees here have produced. The MPO director and deputy director use it frequently, as do planning staff. Partner agencies also love iMap, since it consolidates many data layers in a single location.

Back to top

Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000