Data accessible through INSIDE Idaho are available in a number of projections.  

IDTM
For statewide data sets, the Idaho Transverse Mercator (IDTM) projection is the Idaho state standard.  

A discussion of the IDTM projection can be found here.  

UTM
Many federal entities maintain data in the Universal Transverse Mercator (UTM) projection.  Idaho is split into two UTM zones: Zone 11 (west of 114º W longitude) and Zone 12 (east of 114º W longitude).  

Geographic
Some federal entities maintain data in a Geographic Coordinate System.  The geographic projection creates a rectangular map by spacing the lines of latitude and longitude equally. 

State Plane
Many local entities maintain data in a State Plane projection.  Refer to the metadata for a given theme to determine the specific parameters for any given State Plane projection.

Parameters for the projections mentioned above can be found here.

Datum

Most data are available in either NAD27 or NAD83.  Refer to the metadata for a given theme to determine the datum.

Compression

Most data have been compressed into ".tgz" files (i.e. a tar file was created and then compressed using gzip) or ".zip" files.

Numerous commercial and shareware tools for extracting data from compressed files are available from many sources.   For example, newer versions of WinZip and PKzip will de-compress ".tgz" and ".zip" files.

Downloadable GIS Data Formats

GIS downloadable data can be downloaded to your computer. Use downloads with your GIS software to create a maps or perform analysis. 

Data accessible through INSIDE Idaho are available in a number of GIS formats.

Drawing Interchange File (.dxf)

The Drawing Interchange file (DXF) format, is an industry standard interchange file format used to transfer data between CAD and GIS applications. 

ERDAS_IMAGINE_(.img)

ERDAS IMAGINE .img files store raster data using the ERDAS IMAGINE Hierarchal File Format (HFA) structure. Each .img file stores basic information about the file including file name, layer name, number of layers, and last modification date. Each raster layer within a .img file has its own ancillary data, including the following parameters: height and width (rows and columns), layer type (continuous or thematic), data type (signed 8-bit, floating point, etc.), compression, and block size. Attribute data included in a .img file includes histogram, contrast table or class definitions, statistics, map information, and map projection information. For faster screen display of very large data files, IMAGINE can also use reduced, subsampled raster layers called pyramid layers. Pyramid layers may exist within the .img file or externally as a .rrd file.

ESRI_Coverage

A coverage is a proprietary vector format used by ESRI software. Coverages are the original storage format for ArcInfo. Coverages are a collection of files located in multiple directories. 

ESRI Shapefiles (.shp)

A shapefile stores non-topological geometry and attribute information for the spatial features in a data set.  A shapefile consists of a set of 3 mandatory files, along with several optional files. Each file in the set shares the shapefile name with a different extension. The main file (*.shp) stores the geometry and must always have an index file (*.shx). A dBASE file (*.dbf) stores all the attributes of the shapes in the main file.  Additionally, a projection file (*.prj) stores the projection information.

For more information on ESRI shapefiles click here.

ESRI Interchange (.e00)

The ESRI E00 interchange data format allows all spatial and descriptive information for vectors and rasters to be combined into a single ASCII file.  The file can be used to move themes into and out of ESRI software.

ESRI GRID

The Arc/Info Binary Grid format is the internal working format of the ESRI Arc/Info Grid product. It is also usable and creatable within the spatial analyst component of ArcView 3.x.  It is a tiled format with run length compression capable of holding raster data of up to 4 byte integers or 4 byte floating data. 

ESRI Personal Geodatabase

ESRI Personal geodatabases use the Microsoft Jet Engine database file structure to persist GIS data. Personal geodatabases are much like file-based workspaces and hold databases up to 2 GB in size. Personal geodatabases are ideal for working with smaller data sets for GIS projects and in small work groups.

GeoTIFF

The Tagged Image File Format (TIFF), developed by Aldus Corporation, is an industry standard for data storage and data transfer across operating system environments and applications.  A GeoTIFF takes the TIFF format a step further including geospatial information (such as projection, datum, etc.) in the file. For more information click here.

IBN

Raw Binary LIDAR Files (*.IBN). A proprietary binary format for Raw LIDAR point files.

MrSID (.sid)

MrSID is an acronym for Multi-resolution Seamless Image Database, a powerful wavelet-based image compressor, viewer and file format for massive raster images.  These data can be viewed in a variety of GIS software applications.

Multiple

Data are available in multiple file formats.  Refer to the file metadata for the data set in the data series for the file format.

TIFF with a World File (.tif, .tfw)

The Tagged Image File Format (TIFF), developed by Aldus Corporation, is an industry standard for data storage and data transfer across operating system environments and applications. It is one of the most versatile bitmaps available.  A world file (.tfw) accompanying the .tif file contains spatial information about the data.

USGS_dem (.dem)

United States Geological Survey Digital Elevation Model data format.   These data can be viewed in a variety of GIS software applications.  Additional information about the USGS DEM format can be found here.  If you would like to download a free viewer from the USGS to view these data click here.

USGS_doq (.sws, .ses, .nws, .nes)

Data in this format are in a native USGS single-file format.  They are really a BIL format without a separate header file.  You can't view images with these extensions directly in ArcView and/or ArcInfo.  However, the Washington State Geospatial Data Archive has excellent information about how to manipulate  these images so that you can view them in ArcView and/or ArcInfo.  If you would like to download a free viewer from the USGS to view these data click here.

File Naming Convention

The naming convention most files adhere to is:

Description_Spatial-Organization_Source.tgz

Description: a set of characters to uniquely describe the theme.

Spatial-Organization: a short identifier for the area covered by the theme (e.g.: "id" signifies that the theme covers the entire state of Idaho).

Source: the data contributor.

Example:  counties_id_nrcs.tgz

Live Data & Map Services Formats

Live data and maps allow direct interaction with content. Content is delivered in one of two ways

• Map images generated from data on the map server. 
• Compressed vector features streamed to you and displayed in your GIS software. 

ArcIMS

ArcIMS deliverers dynamic maps and GIS data and services via the Web. These live map services allow direct interaction with content. Data is delivered in one of two ways: as map images generated from data on the map server or as compressed vector features streamed into your GIS software. 

WSM

The OpenGIS Consortium (OGC) Web Map Server interface implementation specification (WMS 1.0) allows map servers to create and send standard map images over the Web as GIF, PNG, or JPEG in a manner that lets client software overlay and display multiple maps from multiple servers – and even different vendors. The use of WMS as an extension to the Clearinghouse allows existing data holdings, described in metadata, to be viewed in this standard way, giving prospective data clients the chance to visually explore the spatial data behind the Clearinghouse from potentially multiple sites.

ArcGIS Server

ESRI ArcGIS server is a server-based GIS. It is a platform for Internet GIS-based applications and services for spatial data management, visualization, and spatial analysis.

Static Map Images

Static maps are map image files. You cannot directly interact with static maps as you do with streaming maps. These maps can be previewed online and then downloaded for use on your computer.

PDF

Portable Document Format. This is a file format in which formatted documents can be transferred over the Internet. PDF files are readable with Adobe Acrobat Reader, an application which can be downloaded from the Adobe Web site at no charge.