Hunting Washington Forum

Community => Advocacy, Agencies, Access => Topic started by: fremont on September 12, 2014, 06:35:44 AM

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Title: WDFW's GoHunt mapping software--which datum?
Post by: fremont on September 12, 2014, 06:35:44 AM

I'm trying to figure out what map datum is used for the GoHunt maps.  I'm guessing NAD 1983 but cannot confirm through my searching.

Anybody know?

Title: Re: WDFW's GoHunt mapping software--which datum?
Post by: Curly on September 12, 2014, 08:51:04 AM

Quote from: fremont on September 12, 2014, 06:35:44 AM

I'm trying to figure out what map datum is used for the GoHunt maps.  I'm guessing NAD 1983 but cannot confirm through my searching.

Anybody know?

My guess is NAVD 88  (for vertical)

Horiz datum is likely NAD 83 since it is the official State Plane Coordinate system.

Title: Re: WDFW's GoHunt mapping software--which datum?
Post by: timberghost72 on September 12, 2014, 01:33:31 PM

Most of the state GIS data uses NAD 1983 HARN StatePlane datum.

Here is an example of GMU spatial metadata from WDFW

 
Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: NAD 1983 HARN StatePlane Washington South FIPS 4602 FeetLambert_Conformal_Conic: Standard_Parallel: 45.83333333333334Standard_Parallel: 47.33333333333334Longitude_of_Central_Meridian: -120.5Latitude_of_Projection_Origin: 45.33333333333334False_Easting: 1640416.666666667False_Northing: 0.0Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pairCoordinate_Representation: Abscissa_Resolution: 0.0003125Ordinate_Resolution: 0.0003125Planar_Distance_Units: foot_usGeodetic_Model: Horizontal_Datum_Name: D North American 1983 HARNEllipsoid_Name: GRS 1980Semi-major_Axis: 6378137.0Denominator_of_Flattening_Ratio: 298.257222101


You can find spatial data here http://geography.wa.gov/data-products-services/data/data-catalog (http://geography.wa.gov/data-products-services/data/data-catalog)

Title: Re: WDFW's GoHunt mapping software--which datum?
Post by: fremont on September 12, 2014, 05:32:24 PM

Per WDFW, it's WGS84.  (Same as Bing & Google maps.)  I've always thought that WGS84 = NAD83, but I'm told that, although the differences are very small, they are not the same.

Thank you for the help.