August 30, 2017
The VT Center for Geographic Information (VCGI) has identified a problem with the compressed versions of Vermont’s 2016 orthoimagery.  This posting describes the problem as well as procedures for fixing the problem depending on how the user acquired the imagery.
Description of Problem
The 2016 orthoimagery was delivered in two raster formats; 1) TIFF and 2) JPEG2000 (*.jp2).  These files were accompanied by associated “auxiliary files”, which are files with an *.aux and *.aux.xml extension.  These files are often generated by Esri software and contain “configuration” information which can affect how Esri and other software interact with raster files.
VCGI has determined that the aux files accompanying the JPEG2000 files included invalid configuration information which causes raster cell values equal to zero (0) to be interpreted as “nodata” by Esri software (as well as some other GIS packages such as QGIS).  Visually this manifests itself as “speckle” in the imagery, however, it can also make its way into derivative raster data since geoprocessing routines will interpret zeros as nodata.
The problem can be easily resolved by removing the *.aux and *.aux.xml files accompanying the JPEG2000 files.  VCGI has already removed these files from the systems we manage (e.g. VT Open Geodata Portal).  Please refer to the procedures outlined below to remove any offending 2016 orthoimagery “aux” files from your system.
  • VT Open Geodata Portal (Portal):  Use this procedure if you downloaded the imagery via the Portal.  NOTE: By default, the Portal’s “Tiled Data Download Tool” will only give users the *.jp2 file, meaning you won’t have any *.aux or *.aux.xml files to worry about.  However, if you bypassed this interactive selection tool and “bulk downloaded” directly from the web folder then you’ll need to follow these procedures (assumes Windows OS).
  1. Browse to the folder where you downloaded the files.
  2. Sort on the “type” column.
  3. Carefully Select and Delete all *.aux and *.jp2.aux.xml
  4. Repeat for all 2016 orthoimagery datasets (e.g. 30cm, 15cm, black & white, color).
  • Offline Data Product:  If you ordered an offline product containing the 2016 imagery
  1. Browse to .\VIL\IMAGERY\VTORTHO\0_3M\CLRIR\2016\COMP
  2. Sort on the “type” column.
  3. Carefully Select and Delete all *.aux and *.jp2.aux.xml
  4. Repeat for these folders
Question? Contact Steve Sharp, VT Ortho Program Manager at


July 26, 2017
Information About the Summer 2017 Parcel Data Update

The following towns are new additions to the VT Open Geodata Portal:

Danville 2016 (NVDA)
Glover 2016 (NVDA)
New Haven 2015 (ACRPC)
Sheldon 2014 (NRPC)
Stannard 2015 (NVDA)
Starksboro 2013 (ACRPC)

The following towns were updated:

Bolton 2016 (CCRPC)
Brattleboro 2016 (WRC)
Bristol 1993 (ACRPC)
Calais 2014 (CVRPC)
Charlotte 2016 (CCRPC)
Chester 2016 (SWCRC)
Colchester 2016 (CCRPC)
East Montpelier 2017 (CVRPC)
Eden 2016 (LCPC)
Enosburgh 2014 (NRPC)
Essex 2016 (CCRPC)
Ferrisburgh 2016 (ACRPC)
Guilford 2016 (WRC)
Hartland 2017 (TRORC)
Huntington 2015 (CCRPC)
Jericho 2016 (CCRPC)
Leicester 2009 (ACRPC)
Lincoln 2014 (ACRPC)
Ludlow 2016 (SWCRC)
Middlebury 2013 (ACRPC)
Milton 2016 (CCRPC)
Monkton 2014 (ACRPC)
Orwell 2013 (ACRPC)
Panton 2015 (ACRPC)
Reading 2016 (SWCRC)
Ripton 2012 (ACRPC)
Salisbury 2010 (ACRPC)
Shelburne 2016 (CCRPC)
South Burlington 2016 (CCRPC)
Stowe 2016 (LCPC)
Tunbridge 2016 (TRORC)
Underhill 2014 (CCRPC)
Waltham 2012 (ACRPC)
Weathersfield 2016 (SWCRC)
West Windsor 2016 (SWCRC)
Weybridge 2006 (ACRPC)
Whitingham 2015 (WRC)
Windsor 2016 (SWCRC)

July 24, 2017

VCGI periodically assesses its suite of Web Map Services to determine if modifications are needed.  We analyze usage statistics to identify "low-use" and "high-use" services, and then target adjustments accordingly.  These adjustments include a range of things such as configuration changes to improve service performance OR adjustments to low-use services to reduce their standing load on the server.  In some cases we may choose to retire services.

So what is changing? Based on our most recent assessment (7/21/2017) VCGI will be making the following changes to our suite of Web Map Services.  The services designated for "retirement" will be supported for the next 90 days (retired on 10/31/2017).  Services designated for "replacement" will also be supported for the next 90 days, but user should begin migrating their applications over to the replacement services as-soon-as-possible.  All services noted in this notice are available via this REST endpoint (

Some Low-Use Services to be Retired on 10/31/2017
  • EGC_services/GCS_E911_RDSNAME_SP
  • EGC_services/GCS_E911_RDSRANGE_SP
  • EGC_services/MAP_VCGI_ALLIMAGERY_SP_NOCACHE_v3 (are being replaced by new services noted below)
  • EGC_services/MAP_VCGI_ALLIMAGERY_WM_NOCACHE_v3 (are being replaced by new services noted below)
Some High-Use Services to be Replaced on 10/31/2017 (replacement services are already available for porting)
  • EGC_services/MAP_VCGI_ALLIMAGERY_SP_NOCACHE_v3 will be retired and replaced by the following (note: the original service layer IDs have been kept the same)
  • EGC_services/MAP_VCGI_ALLIMAGERY_WM_NOCACHE_v3 will be retired and replaced by the following (note: the original service layer IDs have been kept the same)
Life Cycle Policy

All of this and more can be found in VCGI's ArcGIS Server Life Cycle Policy.


Contact Steve Sharp

July 12, 2017

VCGI has begun to explore the possibilities of Power BI, Microsoft's "business intelligence" data modeling and visualization tool.

In this simple example, VCGI downloaded the location of Vermont owned or leased buildings from the VT Open Geodata Portal.  The option to download in "spreadsheet" format was chosen, which provided a CSV file.  The CSV file was pulled into Power BI Desktop and used to create the donut chart and map shown below.

The chart depicts the number of buildings owned and/or leased by specific State of Vermont agencies or departments.  Clicking on one of the sections on the donut chart will "filter" the map to the towns where particular agencies/departments have buildings.

We are just getting our feet wet.  We anticpate doing more as we explore the potential of business intelligence tools to enhance data visualization, data exploration, and data-driven decision making.

P.S. Want to learn more about how the State of Vermont is leveraging tools to extract buisiness intelligence?  Check this out!
Webinar: Business Intelligence Tools for GIS, July 26
Presented by Erik Engstrom, VT Agency of Natural Resources. This webinar will provide an overview on how ANR is using Business Intelligence tools such as Microsoft Power BI and ESRI Operations Dashboard to create meaningful visuals of data for reporting and decision making.

June 29, 2017

How Did The 2017 Spring Collection Go?

The 2017 spring orthophoto acquisition season was challenging.  The specifications for Vermont’s orthos require: 1) no snow, 2) no leaves, and 3) no clouds.  As you can imagine, this is very difficult to achieve in Vermont.  This year was especially difficult.  The acquisition area received widespread heavy snow in late March, resulting in persistent snowpack until the middle of April.  Flightlines in the Champlain Valley were opened on April 13th, with additional lines opened on the 17th.  Unfortunately weather conditions precluded acquisition.  All remaining lines were opened on April 20th.  The first successful flights were on April 23rd, which captured approximately 50% of the acquisition area at 30cm.  The acquisition contractor made a final push on April 27th and 28th to capture additional lines (both 15cm and 30cm) with limited success.  All flight lines were closed by VCGI on May 1st due to leaf-out conditions, which was one of the earliest closures in recent memory. The acquisition contractor is processing the imagery and will have preliminary data ready for review by June.

So What Was Collected In 2017?

The blue areas were collected at 30cm GSD.  The green areas were collected at 15cm GSD.  A large portion of Addison County and the eastern third of the 2017 acquisition area was not acquired in 2017 (shown in yellow).  Most 15cm buy-up areas were not collected in 2017. Click here for a PDF map of 2017 orthophoto acquisition.

When Will These Areas Be Collected?

VCGI is currently working with our contractor to draft a plan for future acquisition of the areas not collected in 2017. We will let everyone know what the plan is when it is completed.