This dictionary provides basic downloads and descriptions of the map features (data layers) in Newton’s GIS database. For a more complete description of the system and of each layer see the full Data Dictionary document. The layers described are created, edited and stored in ESRI’s geodatabase format but have been converted to more common formats for public use.

GIS files are available to download as shape files or as Open Data on GitHub (GeoJSON format). See below for how to use these data layers.

Unless otherwise mentioned, all data layers have the following coordinate information:

• The horizontal datum is NAD83 and the coordinate system is State Plane, Massachusetts - Mainland Zone.
• Units are in feet. The vertical datum (if any) is NGVD29, and the spheroid is GRS1980.

Working with GIS data

A Shapefile is a GIS data format. Newton’s shapefiles were created using ArcGIS, a GIS software package from Esri. Shapefiles can be used in most GIS and CAD software packages. If you do not have GIS or CAD software here are some free tools you can use to work with these shapefiles. All GIS tools have a bit of a learning curve and there is no perfect solution. Click on the tool name for more information.

Desktop Tools

• QGIS – a full featured GIS software package that works in Windows or Mac, has a steep learning curve
• UDig - a simple GIS viewer
• MapWindow – another simple viewer with some added GIS functions

Web Tools

• Carto – a service that allows you to set up custom online maps using shape files, GeoJSON and .csv among other formats. Free for up to 50MB of data. Subscription pricing beyond that.
• GitHub – You can open the GeoJSON files, one at a time and browse each layer. Also lets you download the files in this format for use in various other web applications such as Carto (see above).

Free viewers are required for some of the attached documents.
They can be downloaded by clicking on the icons below.

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