CUGIR offers spatial data files in the following formats:
A format used to package and transfer files in ArcInfo coverage, grid, or INFO format between machines for use in a Geographic Information System. ArcInfo Export files may need to be extracted before importing into a GIS. Users of ArcGIS may be able to use the "Import from E00" (or "Import from Interchange File" in older versions) tool in ArcToolbox. There is also a free conversion utility called Import71, available from ESRI. See the File Formats and GIS Software Compatibility help section for more info.
A proprietary ESRI raster format. Grids are useful for representing geographic variation, spatial modeling and analysis. CUGIR distributes grid data archived and compressed (e.g. as .tar.gz files), requiring extraction before use. See File Formats and GIS Software Compatibility section.
CUGIR offers a small number of data files (e.g. municipal tax parcel datasets for Tompkins County) in computer-aided design (CAD) format for use in AutoCAD and other compatible software (including some GIS programs).
.tif TIFF or GeoTIFF
TIFF is an image format which may or may not have georeferencing information associated with it. GeoTIFF is a TIFF format with additional georeferencing information included in the header of each file and/or in an accessory tiff world file (.tfw). This information allows the map images to be properly drawn within GIS software.
The Digital Raster Graphic (DRG) map images in CUGIR are in GeoTIFF format. These are useful for locating and identifying landscape features and landmarks, and as base layers in mapping projects. Originally published by the USGS by 7.5-minute quadrangle map, CUGIR DRGs are edited and updated by the NYS DEC. Map collars and legends found on print versions ("topo maps") which these are derived from have been removed. In some cases areas outside New York state may be cropped out as well. In order to properly import DRGs into a GIS, coordinate system and projection information must first be defined (see Data Projection section). A DRG index is available listing information about each specific DRG quad set, including map publication date, contour interval and unit, and USGS code. Each quad consists of a set of individual tiles that can be mosaiced together before import or loaded as a set into a GIS. The mosaic process will vary depending on the software being used. ArcGIS users may use the Mosaic to New Raster tool in ArcToolbox. The TatukGIS Free Viewer is a free application that can also be used.
A proprietary ESRI format commonly used for storing vector data, including geographic features and their attributes. Compatible with ArcView, ArcExplorer, ArcInfo or ArcGIS, this format can also be used and/or converted by most popular GIS software applications. In CUGIR, shapefiles have been packaged and compressed. When decompressed, shapefiles contain three or more necessary files to complete a data set, each with the same name but different extension file types. These files must be kept together in the same subdirectory. All are necessary parts of the data theme when used with GIS software. In some cases projection information may be included in an accessory .prj file that allows GIS software to properly draw and place the data layer. If this file is missing users will need to "define " the projection before importing into a GIS (see Data Projection section).
Digital Elevation Models (DEM) are an ASCII comma-delimited format file type used by USGS to distribute digital elevation data. The 7.5-minute DEM (10m by 10m data spacing) provides the same coverage as a standard USGS 7.5-minute quadrangle. DEM uses include volumetric analysis, site location, or drainage basin delineation. Three dimensional "hillshade" views and contour lines can also be created from DEMs. Depending on the GIS software being used, conversion steps may be needed before importing or viewing DEMs. See File Formats and GIS Software Compatibility section for more information.
Electronic versions of some technical documentation and data are posted in CUGIR in Adobe's Portable Document Format (PDF). PDF files maintain the format and look of print documents and are easily accessible to people using various computer platforms. PDF documents require the Adobe Acrobat Reader for viewing and printing. This free software, along with instructions on installation and use, is available on the Adobe website.