Thursday, December 10, 2009

Draft VGIN 5 Year GIS Strategic Plan Public Comment Period

The 2010 VGIN Five Year GIS Strategic Plan is open for public comment. In August, 2009, VGIN began a strategic planning process to bring together geospatial stakeholders to work with us to develop a five year strategic roadmap. This plan defines specific goals and initiatives to help VGIN enhance geospatial functionality, services and strategy in the Commonwealth.

Just as your input was important during the regional town hall meetings, your feedback now on the draft strategic plan is vital

From December 9 to December 23, 2009 VGIN is seeking public input to ensure that VGIN's five year plan serves the geospatial needs of the Commonwealth.

  • To review the 2010 VGIN Five Year GIS Strategic Plan click here
  • Please provide your comments by visiting our online survey
The Strategic Plan will guide VGIN's work and set the direction for the geospatial community by:

  • Providing needed geospatial services to stakeholders;
  • Identifying and developing needed technical and constituent-oriented enterprise geospatial services;
  • Ensuring an interoperable geospatial environment
If you have additional comments or questions a bout the strategic planning process, please direct them to
Thank you.

Wednesday, December 9, 2009

VBMP 2009 Uses Virginia HARN Datum

Starting with the 2009 orthophotography acquisition the Virginia Base Map Program (VBMP) is delivering data in the North American 1983 HARN Datum. Previously, the North American 1983 Datum (NAD83) was used without the HARN upgrade. A High Accuracy Reference Network (HARN) is a statewide upgrade in accuracy of NAD83 coordinates using Global Positioning System (GPS) observations. Generally the HARN upgrade differs from the NAD 1983 Datum by approximately one foot but varies across the state between zero and 3.2 feet.

The mix of datums you are most likely to encounter are NAD83 and NAD83 HARN. The proper geographic transformation between these two datums is the NADCON “VAHPGN” grid transformation method developed by the National Geodetic Survey. In ArcGIS this transformation is referred to as NAD_1983_To_HARN_Virginia.

The datum shift can be corrected in ArcGIS by using the proper geographic transformation in a map document's data frame properties dialog box. The transformation may also be required when using some geoprocessing tools. See this document for more details.

Monday, December 7, 2009

VBMP 2009 Imagery Delivered

The Virginia Geographic Information Network (VGIN) has completed delivery of new imagery to 87 jurisdictions in eastern Virginia (see map) from its 2009-2012 Virginia Base Map Program Orthophotography Program. The imagery was acquired from January to April 2009 and has several new features.

This is the first time VBMP has used digital cameras, the Z/I Digital Mapping Camera (DMC), and the first time the imagery has come with a fourth near-infrared spectral band. The imagery is provided in Virginia state plane coordinates using the improved accuracy of the North American 1983 HARN datum. (The HARN datum typically differ about 1 foot, and up to 3 feet, from the North American 1983 Datum.) The standard resolution is 1-foot pixels, except where jurisdictions ordered upgrades of 3-inch or 6-inch resolution. The deliveries included uncompressed GeoTIFF and compressed JPEG2000 image formats, both of which can accommodate the fourth band. VGIN is providing 3-band MrSID compressed images to jurisdictions upon request. More information on the 2009-2012 Orthophotography Program can be found on the VGIN website.