Maps, Regional Data & GIS
Interactive Trail Map for Durham, NH [Disclaimer: Working Draft]
What is a GIS?
In the most general sense, a GIS (Geographic Information System) is any implementation of a methodology for storing information that has a geographic location associated with it and for analyzing those data. A stack of USGS topographic maps with manually recorded locations of items of interest and some clear plastic overlays for noting relationships among locations or other analytical notes would thereby qualify as a GIS. In fact, before the advent of widely available computing resources, hanging multiple maps on top of each other on a big window to visualize spatial relationships among data on the different maps was a basic, proven, bread-and-butter technique of geographic analysis. Important to note is the concept of data layering that is inherent in this manual technique. The evolution of GIS philosophy and technology to the present has maintained the foundational importance of data layering in both data storage and data visualization and analysis.
Nowadays, the term Geographic Information System is usually used to refer to a computer implementation. Geographic data reside in some form of relational database, and analysis and visualization are accomplished through software designed to work with those data. Typically, the GIS software also includes hardcopy map production functionality to complete the data usage cycle. Onscreen visualization of data is invaluable, but often a picture is still worth a thousand words!
Mapping & GIS at SRPC
SRPC offers a range of GIS and mapping services to its member communities and to local, state, and federal organizations. The GIS staff also provide support to the main Land Use and Transportation programs at the Commission. SRPC has the capability for both high-quality cartographic production and applied geographic analysis. Some of the more common applications of our GIS capabilities are to:
- Land use & suitability, zoning update & mapping
- Economic development and social infrastructure
- Natural resources inventory, conservation planning
- Municipal infrastructure mapping, tax parcel updates
- Hazard mitigation planning
SRPC has a working rate structure for map products requested outside of contractual and other agreements. This schedule is designed to offer reasonable pricing to the indicated audience. Please be aware, though, that this schedule does not constitute a formal GIS Services Policy. GIS staff is working with member communities, the Executive Committee of the Commission, and the Commission staff to develop a comprehensive, fair, and equitable GIS Services Policy that meets the needs of clients and Commission staff. Until such a Policy is established, we will continue to charge for services in a manner which will cover our true cost of service, including GIS hardware and software maintenance and replacement. This guiding principle will also be reflected in any estimate for services that is requested or that is part of a contract.
See below for a complete description of estimates and ordering.
SRPC uses a host of ESRI GIS software, including ArcGIS (ArcInfo) Desktop 9.3, ArcInfo Workstation 8.x, Spatial Analyst for ArcGIS, ArcView GIS 3.3, and (occasionally) PC ArcInfo 3.5.2 for manipulation of legacy PC ArcInfo coverages. This array of tools allows a flexible analytical and mapping process without having to be overly challenged with data compatibility problems. On the hardware side, SRPC has plotting, printing, and digitizing equipment that allow prints ranging in size from 8.5" x 11" (Letter) to 36" x 48" (Architectural E). Our most common standard sizes are 11" x 17" (Tabloid), 24" x 36" (Architectural D), and 36" x 48". SRPC uses primarily 36" wide roll paper in the large-format devices, so prints are restricted to a maximum size of 36" in one direction. Plotting equipment can handle up to 42"-wide media, but SRPC does not normally stock media of this width. Use of media wider than 36" would, therefore, incur increased cost with special purchase of media.
For questions about GIS services at SRPC or about specific projects, please call the Commission at (603) 742-2523 or send and email to firstname.lastname@example.org
SRPC maintains a wealth of natural resources, municipal, transportation, demographic, and other socio-economic data that can be displayed on maps. Some of these layers include:
- Conservation & Public Lands
- Native Ecosystems
- Digital orthophotos
- Tax parcels (where available)
- Infrastructure (sewers, storm water drainage system, critical facilities, etc.)
- Public transit routes
- Traffic Counts
- Roads with names and statutory, regulatory, and traffic engineering attributes
Roughly 70% of our GIS data comes from or is derived from data supplied by other state, federal, and local governments and offices or by private organizations. A substantial amount of this data comes from the NH GRANIT GIS system at the Complex Systems Research Center, University of New Hampshire, Durham. This system is the official New Hampshire GIS data repository. Another significant portion of our data comes from NH Department of Environmental Services and NH Office of Energy and Planning. The other roughly 30% of our data were developed in-house for particular projects. Many of these data are specific to individual communities but may be of a type that is available for multiple communities, if not region-wide.
SRPC's GIS data are in various formats, most of them ESRI formats: ArcInfo coverage, shapefile, and geodatabase. We also have some data in the form of georeferenced CAD files (.dxf, .dwg, .dgn, etc.). Virtually all datasets are in NH State Plane coordinates (Transverse Mercator projection), NAD 1983 (feet).
NOTE that at this time SRPC does not have a compiled data catalog. GIS staff are quite familiar the available data at SRPC, so a phone call or email should answer a majority of data inquiries. Because the volume of GIS data at SRPC is enormous and metadata are not completed for most datasets, creating a comprehensive data catalog is not possible at this time. Where time and funding permits, GIS staff will create metadata for the most widely useful datasets, and this effort?over time?may allow creation of a data catalog.
GIS Services: Estimates and Orders
Please follow this simple process to request estimates for mapping services or to place orders for maps:
- Call SRPC at (603) 742-2523 or email us regarding your mapping needs for your project. We can help you by printing an existing map, or making modifications to an existing map, or designing a new project map.
- You will need to tell us the desired data layers, size, title, legend, and any required marginal elements, such as logos or disclaimers.
- If you have an existing SRPC map, locate the map file pathname, usually near the bottom of the map (e.g. u:\proj\mun\nkt\nkt.apr). Please provide us with the pathname when you are ordering.
- GIS staff will prepare a cost estimate for you of the map(s) or services.
- If requested, a draft copy of any map(s) will be made of modified or new maps for your review and editing before final printing.
- Maps may be paid for by cash, check, or municipal purchase order and according to invoice, where applicable.
Maps will be sent via U.S. Mail to arrive within 7 business days, or they can be picked up at our office. Larger size maps will be mailed in tubes. Electronic maps are also available.
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