Esri holds many national and local user conferences throughout the year. Their leading conference happens right about this time each year in San Diego California, with this year’s 34th User Conference landing on July 14-18. Formally known as the International User’s Conference (now just User Conference or UC), it is the premier world GIS event, with participants from 130 countries among the 16 thousand people in attendance. To put that in perspective, by most accounts there are 196 countries in the world. This year the Esri UC drew participants from about two thirds of countries in the world. With the first day dedicated to the plenary session and keynote address, the next four days are packed with 1,397 moderated paper sessions, industry focused sessions and technical workshops organized into 71 different topic areas. All in all it is a bit overwhelming with so much relevant information to choose from and try to adsorb in such a short period of time.


MB1In order to energize you for the week of information overload, the first day is all about the big picture, success stories and what coming in future releases of ArcGIS software. This is all done wrapped in a wall of screens with beautifully orchestrated music and graphics to produce a completely immersive experience.


Esri Founder and President Jack Dangermond opened the conference with the theme “GIS – Creating the Future”. He shared his perspective that the practice of GIS is at an evolutionary threshold. He sees GIS maturing beyond spatial analysis and moving into full-fledged geo-design, encouraging us to see ourselves as geo-designers to provide the world with fully rounded solutions and alternatives to the many problems we face. He also indicted that he feels that something is a-foot and left us to see if we agree with the rest of the day’s program.


As is Jack’s UC tradition, he shared the best of our work, with submissions from around the world organized by category and displayed, with trends discussed. MD iMap was recognized for the new GIS Data Portal in this part of the plenary and later in the day more fully in a dedicated section on Open Data and the World Bank. CGIS worked as part of the GIS Data Portal implementation team and among other items created the data graphics making the site more attractive and easy to navigate.


First Day Highlights

There was too much on this first day to provide any level of detail on all the incredible presentations in this blog post, instead here are the highlights and links back to the video taken of the presentations in case any of them catch your imagination.

  • The City of Minneapolis and their use of GIS to recover from the devastating blow of the economic down turn of the past few years.  Their team dropped from 8 to 3 GIS professionals. Their success came from completely reinventing their workflow, empowering their cliental to be self-sufficient in working with GIS data and embracing cloud based GIS solutions.
  • The port of Rotterdam’s use of GIS to transform from being the world’s largest port to being the best port in the world. With a ship coming or going every 6 minutes and a 4 hour sail time from the entrance point of the port to the farthest berth, optimizing and managing real time data in their GIS was key to their success in reengineering  port operations.
  • Starbucks IT’s use of GIS to support operations and new store location analysis. Looking to expand in areas with emerging smartphone use (demographics highly correlated to visits to Starbucks) and looking for optimal locations for their Starbucks Evening store rollout (wine, beer, desserts, a spread of cocktail party finger-foods, and more).
  • Singapore’s Urban Redevelopment Authority demonstrated its use of 3D GIS as a crucial planning tool for one of the most densely populated cities in the world. Impact analysis, alternative plans and meeting design metrics in an expedited manner were all successful outcomes of applying geo-design concepts and practices.
  • U.S. Commerce Secretary Penny Spritzer shared her views on the value of open data in a keynote speech titled America’s Data Agency – Expanding Economic Opportunity with Open Data.
  • Dr. Kathryn D. Sullivan, NOAA Administrator, Under Secretary of Commerce for Oceans and Atmosphere, US Department of Commerce (and former shuttle astronaut) shared how she is striving to bring earth science to life for global and national environmental challenges and decisions we all face.
  • Will.i.am (via Skype from Australia) talking to Jack Dangermond after an Esri staffer showed off a prototype of the smart watch he is developing, which includes an a really innovative voice activated Esri mapping application that is a peek into the future (or the past, as I think Dick Tracy had this watch)! Will.i.am explained that this project is part of his efforts in a larger program to empower youth in disadvantaged areas similar to where he grew up.
  • Jane Goodall (video message) provided a follow up to her 2005 Esri UC Keynote address on the threats that chimpanzees face. She talked about how GIS-supported land use management plans for villages around critical habitat areas are making a real difference in conservation efforts to save space for chimpanzees.
  • Sonora Elementary students from Springdale, Arkansas will surely impress you with the way that GIS can be connected with education. Their teacher Charlie Fitzpatrick introduces two of his students and they steal the show talking about their projects.
  • World Health Organization and the Bill and Malinda Gates Foundation representatives (Dr. Bruce Aylward and Dr. Vincent Seaman) delivered a joint keynote presentation on the Global Polio Eradication Initiative. This in-depth presentation stepped though the intensive efforts to reach the last pockets of polio in the most difficult locations to reach on earth, and how GIS is vital tool to for fill this mission.


What was evident from the prominence and diversity of these presentations was there is indeed something “a-foot”. From my perspective it was that Esri did not so much promote what their products could do, instead they let the stories of their products speak for themselves. These were indeed very powerful stories that spoke to the transformative power of GIS in action. There was another thread woven throughout the week’s paper and industry focused sessions that reinforced this notion of real change in the air both with the science and practice of GIS.  It was apparent that the transformative steps Esri has taken with its platform over the past several years and its efforts to make GIS more accessible are all coming together in a unified fashion across all fronts within the organization. Esri seems to be laser focused on its client’s success in a way that I have not seen before, providing complete solution sets for complex problems and implementations.


Special Achievements in GIS

In the middle of the conference each year Esri recognizes exceptional work in GIS by presenting “Special Achievements in GIS” or SAG Awards. This year the State of Maryland was recognized for OSPREY–Innovative use of GIS for Emergency Management that makes a difference. Barney Krucoff accepted the award on behalf of the Maryland Department of Information Technology (DoIT) and the Maryland Emergency Management Agency (MEMA). CGIS is a proud partner in developing the OSPREY suite of tools in support of emergency management and the citizens of Maryland.

Michael Bentivegna (CGIS), Barney Krucoff (DoIT), Mickey Brierley (FEMA – formerly MEMA)

Michael Bentivegna (CGIS), Barney Krucoff (DoIT), Mickey Brierley (FEMA – formerly MEMA)



Towson University’s Center for GIS (CGIS) recently assisted the Maryland Humanities Council (MHC) in their promotional needs by developing a web mapping application that helps MHC audiences and donors quickly identify MHC events that occur near them.


Phil Reese, a GIS Programmer for CGIS, was the primary programmer that developed the MHC web mapping application.  Recently I caught up with Phil to discuss his involvement with the project along with the reasons behind utilizing Mapbox (an open source mapping platform) to complete the project.


Screenshot of the MD Humanities Council Map (Click photo to view the mapping application)

Screenshot of the MD Humanities Council Map

Q:  What options, other than Mapbox, were considered for the development of the web mapping application?

A:  We briefly discussed using the ArcGIS JavaScript API, but decided against going that route because we weren’t planning on creating or using any ArcGIS Server map services for this project.  We also discussed using Leaflet, which is a very popular light-weight JavaScript mapping library that is well documented with a very active community of developers.


Q:  Why did CGIS ultimately decide on using Mapbox for this project?

A:  Mapbox.js was ultimately chosen because of the extensive documentation and examples that exists.  We actually found several examples on the Mapbox.js developer site that almost exactly fit our needs, so we were able to closely follow these examples to jumpstart development of the application.  Another reason we chose Mapbox.js is because it is a plugin for the Leaflet JavaScript mapping library, which means that all of the advantages of Leaflet that I mentioned earlier – great documentation, lots of great plugins, flexible, and efficient – are also advantages for Mapbox.js.  Additionally, Mapbox provides us the ability to use excellent basemaps (and even the ability to customize them to fit our needs) included in a free account that accommodated our expected number of monthly views.


Q: Did you face the need to do a lot of customization, or did you work mostly with the “out of the box” tools that were available?

A:  Most of what we needed to do was “out of the box” in the sense that there were examples of specific pieces of functionality that we desired and thorough implementation descriptions.  We had to use these technologies in ways that suited our needs, so a certain level of development above and beyond what was illustrated in the examples was required, but the documentation and community resources were very valuable for inspiration and direction.


Q:  Were there other technologies you used in conjunction with Mapbox in order to complete the project?

A: We used some very popular (and free) frameworks and libraries that are commonly used across the Internet.  We used Bootstrap for the pre-style user interface components (e.g. think buttons, forms, dropdown menus, etc.) that it provides.  We also used jQuery, which is a JavaScript library that simplifies common JavaScript tasks.


Q: What was the biggest challenge you faced?

A:  Custom functionality that went above and beyond what was illustrated by the examples on the Mapbox.js developer site was sometimes challenging.  We didn’t have a lot of wiggle room to get stuck on certain parts of the application that needed a more custom solution, so it was sometimes a struggle to deliver the promised functionality on-time and under budget.


Q:  What was the biggest surprise you experienced?

A:  The wealth of developer resources available online for Mapbox.js and Leaflet developers.  While we knew this would be an advantage of using these technologies, I think it was a surprise to see how widely used the libraries are.


To view the MHC mapping application, click here.


To view a project sheet on the MHC mapping project, click here.



Esri has a long history of donating software and support to non-profit organizations and educational institutions. This support has come in many forms, from reduced software costs, hosting a dedicated national GIS education conference, mentoring programs and online resources for educators. This tradition of philanthropy ties in with a vision for how GIS can build community and solve problems that the president and owner of Esri, Jack Dangermond, has made a mainstay in the ethos of the company. It is not surprising then that President Obama invited Jack Dangermond to the White House as part of his administration’s ConnectED initiative, to discuss the ways in which Esri has been getting GIS technology into the classroom and lesson plans.


About the ConnectED Initiative
According to the Office of Educational Technology’s ConnectED website, “The ConnectED Initiative announced by the President on June 6, 2013 sets four clear goals to transition to digital learning across the country in 5 years:


  • Upgraded Connectivity: Ensure next-generation broadband and high-speed wireless is available to virtually all of America’s students in their classrooms and libraries.
  • Access to Learning Devices: Ensure students and teachers have access to affordable mobile devices to access digital learning resources at any time inside and outside of the classroom.
  • Supported Teachers: ConnectED invests in improving the skills of teachers, ensuring that every educator in America receives support and training to use technology to help improve student outcomes.
  • Digital Learning Resources: Ensure availability of high-quality digital learning resources and materials for students and teachers.”


How Esri Supports STEM Projects in Schools
In a May 2, 2014 interview with Bloomberg TV, Jack Dangermond, described the project based STEM instruction projects Esri has supported in hundreds of schools across the country. Providing students with GIS tools for real world investigation was exemplified by a classroom project to map lead poisoning in Detroit that was born out of one student’s experience with a brother who was affected. The student’s research indicated that the lead poisonings in the city were correlated to the location of dilapidated housing. The results of the project were used as the basis for further research and the city council supporting a “Get the lead out” campaign that the students participated in.
After hearing about these types of success in supporting education, President Obama asked Jack Dangermond, “Why don’t we scale this up, provide every kid, every school, every teacher with access to this new cloud based geography for learning?” Jack’s response was “Ok, let’s do it,” – meeting the president’s challenge for industry to help transform education, by providing a billion dollar pledge to provide ArcGIS online mapping resources.


More information and an invitation to join the Esri’s ConnectED initiative can be found on the Esri website.


Additional Information on Towson Universities STEM Teaching Community Project can be found here.



On March 18th, I will be attending the 27th annual TUgis Conference, which is hosted by Towson University’s College of Liberal Arts and organized cooperatively with the Maryland State Geographic Information Committee (MSGIC) and the State of Maryland Department of IT (DoIT).  The TUgis Advisory Committee has done a fantastic job organizing the conference.  I look forward to attending Ms. Anne Miglarese’s Plenary Presentation, participating in a panel discussion titled “The Next Generation of Maryland’s Enterprise GIS MDiMap 2.0”, discovering and discussing map design / map application development strategies by checking out the Map-App Competition and catching up with current and former GIS colleagues.


I also look forward to interacting with the undergraduate and graduate students attending TUgis.  Many of the TUgis volunteers are current undergraduate or graduate college students who trade in a day of Spring Break for the chance to explore the GIS world through the TUgis conference.  For some students, TUgis is their first chance to interact with GIS professionals, discover existing trends in the GIS industry, and develop a better understanding of how their research and professional interests best fit in the GIS industry.  The best way to encourage and cultivate that interest is by making sure the students feel that TUgis is as much for them as it is for the established GIS professionals.


Eleven years ago, I attended my first TUgis conference as a prospective graduate student and as a volunteer.  At that time, my GIS experience was limited to a handful of GIS and Remote Sensing courses and a developing appreciation of how GIS can be employed in various professions.  What I remember most about that TUgis conference was the attention the GIS professionals paid to my questions regarding GIS, how GIS can be used in hazards research (my primary interest at the time), and how best to prepare for a career that utilizes GIS technology.  Keeping that positive and encouraging experience in mind, I look forward to sharing my knowledge, experiences, and suggestions with the attending volunteers and students.  I encourage all attending GIS professionals to do the same.


For more information on TUgis 2014, check out the conference website.



No you are not entering the Twilight Zone (that’s Rod Serling’s 5th dimension). The fourth dimension in Geographic Information Systems (GIS) is time. The first two dimensions are what make up a 2D paper map, specifically a grid or coordinate system on which geographic features are rendered. The third dimension is the presentation of height or elevations, which allows for features on a map to be represented in 3D. The fourth dimension accounts for change in mapped features over time.


In the past, most GIS data was used primarily for planning, covered large areas, and was updated infrequently, perhaps annually. Even with GIS data that is updated more frequently, like Landsat satellite imagery of earth (taken every 16 days over the past 40 years), most change analysis in the past was done on an annualized basis between two adjoining years, and visualized as a third dataset. Viewing time aware data in a series, like in a video, was limited to GIS desktop applications. Consequently, time aware visualization was not widely done in GIS. That all changed when ESRI released version 10.1 of their desktop and server GIS software. Streaming large amounts of data became possible, opening the way to a high quality experience with time aware data on the web.  This, in conjunction with an explosion of services providing real-time spatial data, like the national weather service and Twitter, means the time has come for the fourth dimension in GIS.


The Center for GIS’ Work with Time Aware Data
Capitalizing on the success of the Osprey Dashboard Public, the Center for GIS (CGIS) is currently building an internal dashboard application for the Maryland Emergency Management Agency (MEMA) that takes advantage of time aware data. Having the ability to look back in time at the real-time feeds that MEMA aggregates for the Osprey Dashboard will allow emergency managers to compare a current event to past events and assist with planning, exercises, and after action analysis.


Time Aware Map Story of Power Outages Caused by Hurricane Sandy
The following screen shots are from the time aware power outage application currently in development. Hurricane Sandy’s (2012) impact on Maryland has an interesting spatial/temporal story to tell when viewed through the lens on power outages. As you can see from the total Estimated Power Outages graph below, disruption to the electric grid started to increase significantly by 1 pm, Monday October29, 2012 climbing steeply past 10,000 outages. By 7 p.m. power outages passed 100,000, and at 9:30 p.m. outages were climbing even more steeply past 200,000. Estimated outages reached almost 300,000 by 3 a.m. Tuesday October 30, 2012, which was the peak. It took several days of around the clock restoration efforts to bring power outage totals back below 10,000 – late Saturday night November 3, 2012.



Total power outages only tells part of the story. Weather never impacts the whole state at once, or even in the same way. In this case, the coastal track of the storm impacted the counties surrounding the Chesapeake Bay and eastern shore first. The map below shows the outages by county in raw numbers, and as a percentage of customers without power. At 100,000 outages state wide, Harford County was the most impacted with almost 25% of its households/business without power.


From the map below, you can see that at 200,000 outages, the same general pattern held with the counties being impacted. Harford County still the most impacted with 46% of its households/business without power. Note: Western Maryland – Garrett County and Allegany County are without outages roughly 8 hours after the onset of outages in other parts of the state. If this was a normal coastal hurricane, this would be what you might expect, as they usual do not reach that deeply inland, but Superstorm Sandy was not an ordinary hurricane.


At the height of the power outages, 14 hours into the event, with around 300,000 customers affected, the distribution of outage changed dramatically. A second storm came in from the west to join forces with Sandy, enhancing winds and precipitation. In the mountainous region of Maryland this precipitation fell as wet snow. With leaves still on the trees, the weight of the snow caused wide spread outages due to branch and tree falls. At this time Garrett County took the lead as the most affected county, with 57% of customers served being without power. But, this was just the beginning of the power outage problems for western Maryland.


It was not until Wednesday midday that Garrett County’s power outage numbers peaked at 85% of their customers served. By this time, much of the power restoration was complete in other counties or well under way, as can be seen on the map below. With two foot of heavy wet snow blanketing Garrett County, access to the many miles of rural power lines needing repair took several more days. On Sunday November 4, 2012 at 12 a.m., the last time frame shown in this series of map, 30% of the customers in Garrett County were still without power.


This time aware map story of power outages caused by Hurricane Sandy has illustrated the importance of spatial distribution over time, and how it can be visualized to better understand complex temporal relationships in your data. This is particularly true with the information related to emergency management. Dashboard EOC will be ready for use at MEMA as the 2014 hurricane season gets underway. We are excited to put the power of the fourth dimension of GIS in the hands of emergency managers and state officials to better respond to the next big event.


To find out more about MEMA’s Suite of Osprey applications for the public and Emergency responders visit this page: http://mema.maryland.gov/Pages/OSPREYlanding.aspx


Michael Bentivegna

It seems that storms are more intense these days, with the “super derecho” and hurricane Sandy of 2012 and the incredible flooding in Colorado this September. The need to connect the dots between citizens and emergency management officials has never been more important. The Center for GIS at Towson University has been helping the Maryland Emergency Management Agency (MEMA) do just that, with spatial analysis, GIS applications, staffing, and technical assistance, for over 10 years. Much of our work with MEMA has been to put dots on a map in support of their various missions. Most recently, we put dots of a different nature (actually little squares) on a dashboard.


All About the Osprey Dashboard
The Osprey Dashboard provides state officials and the public with a statewide view of several real time data feeds related to emergency preparedness and response. The data includes power outage, NOAA weather alerts, traffic congestion and lanes closed, hospital emergency room status, and shelter status. The Osprey Dashboard leverages these data feeds, which have been used in MEMA’s Osprey EOC mapping application for several years, by continually monitoring the data for threshold triggers. When a threshold is met, a tile in the grid that represents the MEMA regions changes color (traffic light green, yellow, or red). Touching or clicking a tile shows the alert details for each category by county in a popup. Clicking on the specific feature in alert status brings up a map or webpage, either from the authoritative source of the data, or a map derived from that data hosted at MEMA, where you have the choice to explore further, like MEMA’s Power Outage Page. The concept is to quickly be able to see status across the state, investigate further as needed, and follow recovery efforts in progress on your desktop or tablet browser.


While much of the Osprey work is done by our full time professional staff, part of the CGIS mission is to provide students with real world experience. Kurt Karolenko, a particularly talented student programmer, supported the recent Osprey Dashboard work by streamlining the underlying code base to make the application load quickly, and by reorienting the dashboard grid to allow for future data to be added. Stream gauge flood data and local government data (such as emergency school closings by jurisdiction) will be added soon. You can hear about Kurt’s work in his own words in the video below.


Hopefully, our efforts will connect the dots to help inform citizen and state actions during and after the next big event.



For the past several years, Towson University’s Center for GIS (CGIS) has worked with several partners to create a Community Anchor Institution (CAI) database.  The CAI database contains broadband-related data about schools, libraries, public safety facilities, government facilities, higher-education institutions, and some non-governmental facilities.  CGIS relies on local jurisdictions to provide the broadband-related data for the CAI database.


Currently, CGIS provided a representative of each local jurisdiction with an Excel spreadsheet that contains a list of all the jurisdiction’s CAIs.  The representative is responsible for verifying or updating the broadband data associated with each CAI.  Once the data is updated, the representative provides CGIS with the updated Excel spreadsheet and CGIS incorporates the update into the authoritative CAI database.


Baltimore County Community Anchor Institutions

Baltimore County Community Anchor Institutions (Click image for enlarged version)


Recognizing that this workflow can be improved, CGIS has published thematic map services using ArcGIS Online to display the data spatially.  These maps are displayed in an interactive ESRI story map that is customized for each jurisdiction. Instead of providing each local jurisdiction representative with an Excel spreadsheet, CGIS will provide a unique URL for the jurisdiction’s story map.  The story map displays the known and unknown high-speed Internet status of the jurisdiction’s CAI data.  The maps displayed in the application will help the representative quickly identify the CAIs for which broadband access is unknown.  The data can be edited by accessing a verification tool directly from the web mapping application.


This new workflow is a significant improvement in the maintenance of the CAI database.  The new workflow: 1) improves the visualization of the current data through the use of basic thematic mapping, 2) increases automation of the CAI database update process, and 3) provides more control to those responsible for updating the data.


Read more about our experience mapping broadband service and performance across Maryland.




Last week two CGIS employees, Tom Earp (Project Manager) and Melanie Bruce (GIS Specialist), attended ESRI’s 2013 International User Conference in San Diego, California.  I recently sat down with Melanie Bruce to discuss her experience at the annual GIS event.



Q: How many ESRI UC conferences have you attended?


A:  This was my second ESRI conference, the first time CGIS sent me.   This year there were over 12,000 people from 130 countries gathered to talk and learn about GIS.  The enormity of it is still a bit confounding.


Image credit: Kris Krüg

Image credit: Kris Krüg

Q: Many ESRI UC attendees I’ve talked to have mentioned that there are so many exhibits, presentations, and workshops they want to see but they have too little time.  Did you find that to be a challenge as well?


A: Yes, I can relate.  The event is enormous and it is impossible for a single person to see it all or even get close to seeing it all.  I received some good advice from Tom Earp who suggested focusing on one concentration or track.   We both focused mainly on Technical Workshops.  We made sure we did not overlap so that we could cover the most ground, take good notes, and disseminate the information back at the office.  I think it was a good strategy.


Q: Out of the presentations you attended, which did you enjoy the most?


A: From the Plenary, it was really inspiring to see Will.i.am speaking with students from the i.am.angel Foundation.  The presentation by Sam Pitroda, who is an advisor to the prime minister of India, also caught my attention.  What this guy is tasked with will boggle anyone’s mind: planning for the public information infrastructure of over 1 BILLION PEOPLE, of which 30% are living in poverty.


will.i.am speaking with high school students at the Esri UC. Image credit Esri.


Q: Did you attend any workshops this year?


A: Nearly everything I attended was considered a technical workshop.  I focused on workshops concerning using and optimizing ArcGIS Server, various application development topics (e.g. creating .Net Add-ins for ArcGIS Desktop, development with the ArcGIS JavaScript API, etc.), and spatial analytics.


Q: Is there anything you learned from ESRI UC that you expect to apply in your everyday activities at CGIS?


A: In the next few months, I am excited about and hope to touch on 1) the web version of The Operations Dashboard, 2) the GeoEvent Processor Extension, and 3) ArcGIS Professional – Version 11.  I can’t wait!




So the cicadas are coming. What does that mean? There are hundreds of species of cicadas throughout the world but the ones getting the hype right now are the shrimp size Magicicadas or periodical cicadas (13 and 17 year cicadas). Actually there are 24 different “broods” of cicadas that emerge in the spring and summer at different years and in different geographic locations (this is a GIS post after all so I have to use “geo” somewhere). Brood II is a 17 year cycle emerging in 2013 in CT, GA MD, NC, NJ, NY, PA, VA when the soil temperatures reaches  64 F degrees about 8 inches below the surface.


The periodic cicadas live all but a brief portion (three weeks) of their life underground (1-8 feet) as grubs feeding on root juices.  When they emerge to mate they do so in large numbers (i.e. millions, a plague, etc). Actually this is a natural defense called “predator satiation” that ensures enough survivors are left behind to reproduce.


Cicada map, image credit: ABC 7

Cicada map, image credit: ABC 7


Apparently they are not only tasty for birds and other wild predators but also as a delicacy to people as well, according to Jena Jadin, University of Maryland. Other than the loud noises and general nuisance they are not harmful to people. My wife’s niece would dispute that after “colliding” with several during a 5K race in Fredericksburg, VA recently.


A comment I heard the other day “Perhaps the cicadas will not be so bad this year since we have paved so much over the last 17 years.”  A sad commentary if that is true.


Here are some good sites for information and maps:

Mark Helmken, Executive Director of the Center for GIS at Towson University, has over 20 years of experience with GIS, systems engineering, systems integration, and GPS and remote sensing technologies. Mark leads a group of accomplished professionals who provide geospatial solutions to governments, business, and non-profits around the state of Maryland. He works with them to adapt and respond to rapidly changing technologies in the areas of mapping and data management.



Several months ago I worked with my colleagues at Towson University’s Division of Innovation and Applied Research to produce a training video about ESRI’s mosaic dataset.  In the video I described the differences between the mosaic dataset and other ESRI raster storage formats and presented the benefits of using a mosaic dataset to store (and serve) raster data.   What I did not touch on was some of the difficulties one who is new to using mosaic datasets might face.  The intention of this blog post is to fill that gap by explaining some of the issues I recently faced when creating a mosaic dataset.


Over the last couple weeks, I have been responsible for creating a statewide tax map that displays property parcel boundaries throughout Maryland.  The task involved working with thousands of tax map TIFF images that covered all but four of Maryland’s counties plus Baltimore City.  With so many TIFF images to work with, limited processing and maintenance time, and a desire to serve the end product as an image service I decided to create a mosaic dataset.  Creating a mosaic dataset using the default settings produced a couple issues that I had to correct before publishing the mosaic dataset as an image service.


Overlapping Rasters

The figure below shows the problem that existed at the tax map boundaries.  One can see that the white borders of some tax maps obscure the property boundaries shown on neighboring tax maps.


Overlapping raster issue: some tax maps obscure the property boundaries shown on neighboring tax maps. Click the map for larger image.


The problem occurred because the default mosaic method of a mosaic dataset is set to “First”.  This means that the raster shown to the user in the case of overlapping rasters is the raster that was added first to the mosaic dataset.  The solution to the problem is to modify the mosaic dataset’s mosaic method using ArcCatalog or ArcMap. Changing the mosaic method to “min” solved my problem by always displaying the pixel with the minimum value, which is the pixel value associated with the property boundaries.

Overlapping raster issue fixed. Click map to see larger image.

Overlapping raster issue fixed. Click the map for larger image.


Rasters Displaying At Various Scales

Another problem I experienced was that not all of the tax maps showed up at the same scale because not all of the tax maps have the same pixel size.  While this may be acceptable for most applications, I needed all tax maps to display at the same scales regardless of the source data pixel size.


The solution to this problem was modifying the MaxPS field in the Footprint attribute table.  The MaxPS field is automatically calculated when the mosaic dataset is created and is based off the HighPS field that exists in the same attribute table.  As described here, the MaxPS field specifies the minimum scale at which a given raster is displayed.  I modified the MaxPS field by making sure all rasters used in the mosaic dataset had the same MaxPS value.  This ensured that all tax maps display at the same scales.

Modifying the MaxPS field in the Footprint attribute table. Click the image for larger view.

Modifying the MaxPS field in the Footprint attribute table. Click the image for larger view.