Map Service Caching Issues: There’s Always More Than One Way to Fix a Problem

December 10, 2010
Jeremy

Jeremy

A couple weeks ago I was asked to troubleshoot the odd behavior of a cached map service in a FLEX web mapping application.  The application provides users with the ability to view the map at 11 different scales ranging from approximately 1:2300000 to approximately 1:2250.  The FLEX web mapping application uses several cached map services, but one disappeared when a user zoomed into the largest scale possible (1:2250).  This behavior was very odd because the cached tiles existed for the map service at the largest scale (1:2550).  So what was causing the odd behavior?

After comparing the cached services used in the application, I noticed that the cache level scales were all EXACTLY the same except for the largest scale.  (Up to this point I have referred to the largest scale as “approximately 1:2500”.  The true value for the largest scale is actually 1:2254.4677625.)  The cached map service that did not display correctly at the largest scale had its largest scale set to 1:2254.467763 not 1:2254.4677625.  In order for the service to display correctly in the application at the largest scale, I had to replace the cache tiles tied to the incorrect scale (1:2254.467763) with cache tiles created at the correct scale (1:2254.4677625).  So how did I do this?

Most GIS Specialists familiar with creating AGS map service caches would automatically think the solution is to simply delete the old cache level using ArcCatalog and add the new one.  Unfortunately this doesn’t always work.  When I tried this method, I noticed that even though I entered the correct scale (1:2254.4677625), the scale was rounded off to the wrong scale (1:2254.467763) once I applied the changes.  The workaround I used to solve the problem involved editing the service’s configuration file using Notepad ++.  The steps I used are provided below:

1) Open Windows Explorer

2) Navigate to the location of the map service’s cache folder

3) Locate the map service’s cache XML configuration file

4) Open the configuration file with a text editor (e.g. Notepad ++)

5) Manually correct the appropriate scale and save the configuration file

6) Open ArcCatalog, refresh the map service, and re-create the cache tiles for the corrected scale

Hopefully you found this helpful, I also published a blog post a while back on Lessons Learned: Creating a KML-Enabled ArcGIS Server Map Service that might be of use!

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Posted by Jeremy Monn

What Is CGIS Doing for GIS Day 2010?

November 2, 2010
Jeremy

Jeremy

After a weekend of attending Halloween parties and eating entirely too much candy it is a bit much to start thinking about the defining event of November for most Americans: Thanksgiving.  Luckily, as a GIS professional, I can focus on planning for GIS Day 2010 on November 17th. GIS Day is an annual event that occurs during Geography Awareness Week.  GIS professionals and organizations use GIS Day to educate others about GIS using a variety of methods including but not limited to open houses, workshops, and conferences.

Whether organizing events for elementary and middle schools or participating in GIS Day events hosted by other organizations, CGIS has been an active GIS Day participant for the past several years.  This trend will continue this year as CGIS returns to the Crossroads School in Baltimore.  Similar to last year, CGIS plans on working with a 7th grade class to map data they collected in Baltimore.  This year, the 7th graders are collecting information about several points of interest they selected in the Fells Point neighborhood.  They will use this information to create a guide titled “A Newcomer’s Guide to Fells Point”.  On GIS Day, CGIS employees will introduce the 7th graders to GIS and work with them to map their points of interest and walking tour routes using Google Earth.

Additionally, CGIS will be participating in the Maryland State Highway Administration’s (SHA) GIS Day event located at the SHA building in Baltimore.   SHA’s GIS Day event will actually take place on November 30th instead of November 17th.  SHA employees are invited to the event to learn more about what GIS is and how it can be utilized by an organization like SHA.  Along with making a presentation on transportation-related projects CGIS is currently working on, CGIS will be manning a booth at the event to provide general information about GIS and specific information about CGIS’s involvement in the GIS community.

Visit CGIS’ Web site to view detailed information about GIS Day activities for this year and previous years!

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Posted by Jeremy Monn

Geography and Bubbles: Understanding Why My High School Mascot Was a Bubble

September 16, 2010
Jeremy

Jeremy

When I moved to Maryland several years ago to attend Towson University, I found that an easy way to break the ice with a group of people I didn’t know was to ask them “What was your high school mascot?”  Usually the question produced quizzical looks, probably because they were wondering why I cared, but most would provide expected answers like a bulldog, eagle, wildcat, lion, etc. Once they provided their answers, I provided them with a great laugh by informing them that my high school mascot was a bubble.  More specifically, we (my classmates and I) were not referred to as “Bubbles” but as “Bubblers”.

Readers of this blog may be asking themselves, why in the world would a high school select a bubble as a mascot?  This is a good question, and it is one that can be answered by understanding the physical and human geography of my hometown.  The town, and thus eventually the high school I attended, owes its existence to its site and situation.  Located along a stream fed by dozens of underground springs and close to abundant timber, limestone, and iron ore sources the area became a prime location for the development of a charcoal iron works in the 1750’s.  Not only did the stream provide power to the iron works (a dam was constructed for this reason, thus creating Children’s Lake located at the center of town), but is also provides the town its name.  Just north of Children’s Lake, at a place known locally as “The Bubble” the underground springs rush to the surface creating a boiling appearance, hence the town’s name: Boiling Springs.

Citizens of Boiling Springs and the surrounding areas ascribe many different meanings to The Bubble, making it a key factor in many people’s “sense of place” of the town.  Scuba divers view The Bubble as an entry way into an underground (and underwater) world that many never see, local high school students view The Bubble as a place to settle differences off campus or to just hang out, significant others view it is a starting place for a romantic walk along the stream and lake, and former residents like myself view it as a place to remember when they are homesick.  Knowing this, is it any wonder why students attending Boiling Springs High School are referred to as Bubblers?

Children's Lake...Photo Credit: Flickr User cthoyes

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Posted by Jeremy Monn

Mapping Broadband Service and Performance across Maryland

July 28, 2010
Jeremy

Jeremy

Usually when I watch television I channel surf during commercials.  I feel like advertisements constantly compete for my attention, so when I have the power to avoid them altogether I make sure to take advantage.  However, over the past year Verizon and AT&T successfully caught my attention with commercials that feature maps comparing the providers’ 3G networks.  What was so interesting about these commercials is that the maps being compared in the commercials never seemed to be the same.  I was left wondering: Are the providers using different data collection units (e.g. counties vs. census tracts), different variables (e.g. download speed vs. availability), or a combination of different techniques to create the different maps? These questions underscore the need for a single map showing the coverage areas of each service provider in a given area.

Not long after these commercials began airing, Towson University’s Center for GIS (CGIS) partnered with the Maryland Broadband Cooperative, Salisbury University, and the Maryland Department of Business and Economic Development to map the service coverage areas and market performance of Maryland Broadband service providers. Since November of 2009, the partners listed above have primarily focused on collecting service coverage data from broadband service providers and performing outreach to generate data on the performance of internet connections throughout Maryland via the Maryland Broadband Speed Test (see Steve Fabijanski’s blog post for more information on the Maryland Broadband Speed Test).

For much of the summer, interns associated with CGIS and Salisbury University’s Eastern Shore Regional GIS Cooperative (ESRGC) have been validating data from mobile wireless broadband providers by testing upload / download speeds at 1,472 locations across the state.  Upload / download speeds are tested using four cell phones, each equipped with the Android operating system, and associated with the different mobile broadband providers (AT&T, Sprint, T-Mobile and Verizon).  The locations were identified by creating a 4km2 grid of the state, and creating points at the intersection of the grid squares.  The routes the interns follow for a given day are created using ESRI’s ArcLogistics program, which designs a route tailored to the length of the workday, the time spent at each location, and the number of unverified points remaining.

As the data is being collected and verified, the CGIS development team has been busy creating the on-line mapping application that will make the broadband data available to the public. Users will be able to indicate an address and the application will return a list of the broadband providers and service technologies available. Users will also be able to report non-served areas and map errors, and take the speed test. The mapping application is scheduled to launch in early September.

Visit http://www.mdbroadbandmap.org/ for more information regarding the Maryland Broadband Mapping Initiative and to test your connection speed.


1 Comment | IT, Mapping, Students | Tagged: , , , | Permalink
Posted by Jeremy Monn

TUGIS 2010

June 1, 2010
Jeremy

Jeremy

There are many reasons I enjoy attending professional conferences, including learning about what others in the GIS world are working on, catching up with colleagues I have not seen in a while, and getting a break from cubicle-life for a couple days.  I had the chance to accomplish all these feats while attending Towson University’s annual GIS conference (TUgis) earlier this week.  The conference quickly flew by and now I’m back in my cubicle left to reflect on TUgis 2010.  The following are specific and general observations regarding the conference.

TUgis 2010’s theme, “GIS in Budget Constrained Times: Doing More with Less” seemed especially pertinent considering the real budget difficulties facing individuals, businesses, and governments in today’s fitful economy.  The number of conference attendees and exhibitors were noticeably down due to the difficult economic times, but the quality of the presentations remained high.

Most of the presentations I attended tied into the conference’s theme well.  Jennifer Pfister’s (BioHabitats, Inc) presentation focused on the use of “freeware” in order to prioritize where non-native invasive species removal resources should be used in Fairfax County, Virginia.  Sharing data, services, and infrastructure was the cost-saving theme reiterated throughout the MDiMap mini-workshop.

The education application presentations on the conference’s second day stressed the importance of volunteerism and giving back to the community where one lives and works.  This was especially true in Jessica Wright and Lacy Baker’s (California University of PA) presentation, which focused on a service learning project that involved the development and maintenance of a GIS that provides local volunteer firefighters with information regarding hazards they may encounter at a destination.  The discussion that followed regarding the student’s training of the volunteer firefighters in the system’s use as well as a more general discussion of volunteerism was very interesting.

While I enjoyed all the sessions I attended, I believe the underlying message delivered by the presentations in the education application session stuck with me the most.  During today’s difficult times it is understandable that individuals and businesses are increasingly concerned about pinching every penny and making sure employees are “billable”.  However, it is especially important today not to lose sight of the importance of volunteerism.  Volunteer work may not help with the volunteer’s budgetary concerns, but they along with the community served will reap real benefits from the volunteer work completed.

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Posted by Jeremy Monn

Preview of the MDiMap Mini-workshop at TUgis2010

May 17, 2010
Jeremy

Jeremy

The 23rd annual Towson University Geographic Information Sciences (TUgis 2010) conference will be held on Monday, May 24th and Tuesday, May 25th at the University Union on Towson University’s campus.  Each day starts off with a plenary presentation, which is followed by three concurrent sessions throughout the day with lunch and several breaks mixed in.  During the concurrent sessions, conference attendees may choose from several 15-minute presentations and several 45-minute mini-workshops, ranging on topics from environmental applications to GIS career development.

One of the mini-workshops taking place at TUgis 2010 will focus on the MDiMap initiative. It will take place in the Chesapeake I room of the University Union on Tuesday, May 25th from 3:30 – 5:00pm. Watch the interview below where Ashley Buzzeo of Towson University’s Center for GIS and one of the MDiMap mini-workshop presenters describes MDiMap in general and the MDiMap mini-workshop specifically.

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Posted by Jeremy Monn

You’ll see me @ Towson University’s 23rd Annual GIS Conference

April 15, 2010

Jeremy

Jeremy

The annual Towson University Geographic Information Sciences (TUgis) has been an important part of my GIS career throughout the last seven years.  My career at Towson University began at TUgis 2003, when Dr. Jay Morgan interviewed me for a graduate assistantship.  I would not be a Towson University alumni or a current Towson University employee were it not for that interview.  TUgis 2005 was the venue I chose to present the results of my graduate school research, which helped me obtain my graduate degree.  Subsequent TUgis conferences have been venues for presenting projects I have worked on since becoming a full-time CGIS employee in August of 2005.

This year’s TUgis will take place on May 24th and May 25th.  For those readers who will be attending TUgis for the first time this year, below are a few things to check out.

  • Job Mart – Conference attendees interested in finding or advertising a GIS job are encouraged to participate in TUgis’ Job Mart.  Prospective employers can also set up interview slots during the conference by contacting Dr. Shang Kou Lou of Towson University’s Department of Geography and Environmental Planning.
  • Map Gallery – Conference attendees are encouraged to vote on the best maps submitted for the TUgis 2010 Map Design Competition.  Conference attendees interested in competing must submit their map to Towson University’s Department of Geography and Environmental Planning by 3:00 pm on Friday, May 14th.
  • Student Presentations – Every TUgis conference I have attended has dedicated one or more sessions to student presentations.  Support the student presenters by attending one or more of the presentations.
  • Workshops – TUgis conferences also make workshops available, which typically cover an entire 90-minute session.  If you are interested in learning more about the MDiMap initiative, make sure to check your conference program for the MDiMap Workshop.
  • Ice Breaker Social – Enjoy food, drink, and company at the end of the conference’s first day (5:00 pm – 7:00 pm) at the Ice Breaker Social.  Who   knows, maybe you’ll win a door prize?

For more information about TUgis 2010, visit http://tugis.towson.edu/.

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Posted by Jeremy Monn

Why am I a geographer?

March 4, 2010
Jeremy

Jeremy

In January, I found Clay Hickson’s “My First Business” blog post very interesting.  The blog clearly illustrates how childhood interests and experiences can help determine one’s professional career later in life.  After reading Clay’s article, I could not help but wonder what childhood interests and experiences led me to becoming a professional geographer.

Like most professional geographers, I have always had an interest in maps.  As a child, I actually looked forward to dentist appointments because

(1) it meant an afternoon free of school and

(2) it also meant free access to maps found in the mountain of National Geographic magazines piled on the waiting room end table.

Jeremy, age 7, and his father

In middle school and high school, I spent many study-hall periods and some class periods drawing mental maps of places I visited or knew well.  Today, give me an atlas and I quickly lose track of time as I analyze and deconstruct maps of different countries or regions.

While this seemingly innate interest in maps was important in priming my interest in geography, it was time spent outdoors that cemented my interest.  Annual backpacking trips in northern Pennsylvania with my father, brother, and friends provided me with learning opportunities which were directly or indirectly tied to geography.  These trips are where I first learned how to navigate using a contour map and compass (GPS, what’s that?).  I learned:

  • about the relationship between soil type and vegetation,
  • about the relationship between land cover and stream quality / velocity,
  • and about the risks one takes when setting up camp in a floodplain (we had to hastily evacuate in 1992 when the remnants of Hurricane Andrew passed through). 

I am a professional geographer today largely as a result of these childhood experiences.

1 Comment | Mapping, TU Faculty & Staff | Tagged: , , , | Permalink
Posted by Jeremy Monn

What does being snowed in mean for CGIS and MEMA?

February 10, 2010
Jeremy

Jeremy

At the time of this writing (Tuesday afternoon), many Marylanders are still digging out of last weekend’s blizzard, which dumped at least two feet of snow in most locations.  Maryland is in its fourth day of a State of Emergency with a new snowstorm approaching the region with the possibility of dumping an additional foot or more of snow.  In my Baltimore City neighborhood, the impending snowstorm has residents scrambling back to the grocery store, clearing their flat roofs, and in some cases working with their neighbors to shovel out their block that has yet to be cleared from the last snowstorm.  Once the next storm begins, I along with many other Marylanders will likely hunker down indoors to wait out the storm.

Canton residents removing snow

However, it’s important to remember that there are many people who must work during extreme weather events.  Among others, these include:

  • Snow removal personnel
  • Utility workers
  • Emergency responders
  • Emergency management professionals

Towson University’s Center for GIS (CGIS) has supported the Maryland Emergency Management Agency’s (MEMA) State Emergency Operations Center (SEOC) during times of disaster.  In the fall of 2003, CGIS employees provided 24/7 support to the MEMA’s SEOC during Tropical Storm Isabel by fielding ad-hoc map requests and conducting spatial analysis tasks, including providing reasonable estimates of the areas that would be flooded by the storm using storm surge height predictions made by the National Weather Service.  One of the outcomes of this experience was a white paper developed by Dr. Jay Morgan who was then Director of CGIS which outlined lessons learned regarding the use of GIS by the MEMA’s SEOC before and during a disaster.

CGIS continues to support the MEMA’s SEOC during disasters.  Throughout this last blizzard two CGIS employees, Joe Gibson and Matt Miller, provided on-site support to the MEMA’s SEOC by mostly fielding ad-hoc map requests.  With the continuation of Maryland’s State of Emergency and the threat of another major snowstorm, Joe and Matt may be asked to support the MEMA’s SEOC for the second time in a span of one week.

Visit NOAA’s interactive map if you’re interested in local snowfall totals from last week’s storm in Maryland and Northern Virginia.


Leave a Comment » | Community Outreach, Homeland Security, Mapping | Tagged: | Permalink
Posted by Jeremy Monn

CGIS and FEMA’s Regional Catastrophic Preparedness Grant Program

February 4, 2010
Jeremy

Jeremy

The recent earthquake in Haiti not only acts as reminder of the vulnerability of communities to disasters caused by natural (earthquakes, hurricanes, tornados, etc.) or man-made (nuclear power plant accidents, toxic material releases, etc.) events but it also reminds us that some disasters are so catastrophic that the demand for emergency response exceeds the local jurisdiction’s supply of emergency response equipment and personnel.

So, what are emergency managers to do when they are overwhelmed by a catastrophic disaster within their jurisdiction? An obvious option is to ask for assistance from surrounding jurisdictions by requesting emergency resources (e.g. search and rescue teams, ambulances, EMTs, etc.).  However, in order for these requests to be processed quickly and efficiently, emergency managers within each jurisdiction need to be:

(1)    using a common language when discussing the availability of emergency resources and

(2)    leveraging resource management systems that can “talk” to other jurisdictions’ resource management systems (i.e. are interoperable).

The Federal Emergency Management Agency (FEMA) acknowledges this and developed the NIMS 120, which is a list of authoritative definitions for 120 emergency resources that are likely to be shared by jurisdictions during a disaster.  However, there are state-specific emergency resources that jurisdictions share during a disaster that are not explicitly defined by FEMA.  This gap in common definitions has the potential to disrupt or delay the interstate sharing of resources not listed in the NIMS 120.

Through the Regional Catastrophic Preparedness Grant Program (RCPGP), Towson University’s Center for GIS (CGIS) is working with the University of Maryland’s Center for Health and Homeland Security (CHHS) to fill this gap for the six jurisdictions (Delaware, the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia) making up the national capital region.  CGIS is developing survey instruments that:

(1)    will identify the non-NIMS 120 emergency resources that each jurisdiction has available for emergency response and

(2)    assess the existing resource management systems of each jurisdiction. 

CGIS will compile the survey results and provide CHHS a list of options and recommendations for definitions for the non-NIMS 120 emergency resources identified by the surveyed jurisdictions.  CGIS will also provide CHHS options and recommendations for enhancing / improving the interoperability of resource management systems across the region.

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Posted by Jeremy Monn

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