Proposition for a Timberland Administration GPS Information Precision Standard.


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The GPS exactness standard is in light of solicitations from line and ... Match any GPS precision to the undertaking prerequisites and not permit innovation to direct ...
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Slide 1

Proposition for a Forest Service GPS Data Accuracy Standard Forest Service 2003 Geospatial Conference Colorado Springs, Colorado Ken Chamberlain, BLM Oregon State Office

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About the Proposed GPS Data Accuracy Standard

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Background In April 2002 the FS GPS Steering Committee was coordinated by Chuck Dull, Assistant Director of Engineering, Geospatial Applications to build up a GPS Data Accuracy Standard. The GPS precision standard is in light of solicitations from line and staff officers at the national, territorial, and backwoods level. The goal is to give direction on evaluating the exactness, quality, and appropriateness of GPS information utilized as a part of GIS and Land Management The DRAFT GPS Data Accuracy Standard record is accessible at: . http://www.fs.fed.us/database/gps/gps_standards/GPS_Data_Standard.pdf

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Elements of GIS Data Quality Lineage Logical Consistency Completeness Attribute Accuracy Positional Accuracy The GPS Data Accuracy Standard covers these components Connectivity Shape Relative Position Source Position Horizontal Position Vertical Position "Genuine" position

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Purpose of a GPS Data Accuracy Standard Defines a technique for testing and reporting GPS precision that is reliable with FGDC, National Standard for Spatial Data Accuracy (NSSDA). Gives GPS Test information to help coordinating GPS hardware and field methods to GIS and mapping precision prerequisites. Coordinate any GPS precision to the undertaking prerequisites and not permit innovation to manage the exactness.

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What the GPS Data Standard does NOT do Does not characterize limit precision values. Try not to direct the base precision required for a given GIS topic or Mapping application. Does not indicate collector sort and recipient arrangement Does not address Data ancestry, legitimate consistency or fulfillment Therefore: The information steward or application supervisor are in charge of choosing the exactness values that are adequate on a topic by-subject or application premise.

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Parts of GPS Data Accuracy Standard Section 1: Introduction Section 2: GPS Accuracy Testing Guidelines Section 3: Table of Tested GPS Accuracy Section 4: GPS Accuracy Reporting and Metadata References Appendices: 1. Utilization of the GPS Data Accuracy Standard 2. National Standard for Spatial Data Accuracy Spreadsheet 3. Equations: Horizontal Accuracy utilizing NSSDA recipes 4. USFS GPS Test Networks 5. Existing Standards

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Development of the proposed GPS Data Accuracy Standard Based on a survey of existing FS and Federal exactness norms. Intended to consent to the Federal Geographic Data Committee (FGDC), Geospatial Positioning Accuracy Standards Part 3, NATIONAL STANDARD FOR SPATIAL DATA ACCURACY, FGDC-STD-007.3-1998. (NSSDA).(Appendix 2) Intended to characterize testing methodology that meet NSSDA and meet metadata report prerequisites by: 1) utilizing existing FS GPS test information 2) Users testing their own particular information

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Why embrace FGDC Requirements? Official Order 12906 , Coordinating Geographic Data Acquisition and Access: the National Spatial Data Infrastructure: "Government organizations gathering or creating geospatial information, .. might guarantee… . that information will be gathered in a way that meets every single important standard embraced through the FGDC procedure." 1994

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Overview of FGDC Geospatial Positioning Accuracy Standards Part 1: Reporting Methodology: regular precision reporting for all geodata sorts. Section 2: Geodetic Networks Part 3: National Standard Spatial Data Accuracy: for computerized geospatial information that is not obliged by scale. Section 4: Architecture, Engineering, Construction, and Facilities Management Part 5: Navigation Charts and Hydrographic Surveys

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Part 1:Reporting Methodology, FGDC Geospatial Positioning Accuracy Standards OBJECTIVE: To give consistency in reporting the precision of point geospatial information gathered by various exercises OBJECTIVE: Develop a FGDC archive with a solitary technique that characterizes how to report the positional exactness for all point geospatial information gathered, created, or dispersed by the Federal government and the Nation. Exactness reporting for all geospatial information is required to be accounted for at the 95% certainty level.

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Part 3: National Standard for Spatial Data Accuracy (NSSDA) NATIONAL STANDARD FOR SPATIAL DATA ACCURACY , actualizes a testing and factual strategy for positional precision of completely georeferenced maps and advanced geospatial information , in either raster, point, or vector design, got from sources, for example, aeronautical photos, satellite symbolism, and ground reviews . "The NSSDA is expected to supplant the 1947 National Map Accuracy Standard." (" A proposition for a National Spatial Data Infrastructure Standards Project", http://www.fgdc.gov/guidelines/records/recommendations/progpas3.html NSSDA composed by the FGDC Subcommittee for Base Cartographic Data

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National Standard for Spatial Data Accuracy NSSDA Statistics Compares information to higher request positions Based on Root Mean Square Error (RMSE) 95% certainty Horizontal round mistake If blunder is equivalent and ordinarily circulated in both x and y, level precision is 1.7308 * RMSE r reports mistake in ground separation

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FGDC – Geospatial Positioning Accuracy Standards-Part3: National Standard for Spatial Data Accuracy Compare Data with Independent Data Set of higher exactness N=20 least RMSEr = sqrt[S((Xt-Xg) 2 +(Yt-Yg) 2 )/N] Report Horizontal blunder at 95%= 1.73xRMSEr Report precision as Tested or Compiled to meet Report Accuracy in ground separation and units

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Comparing NSSDA with NMAS

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Publish Test Results in the "Table of Tested GPS Accuracy" as a major aspect of the Standard. This Table is a "living record" will be redesigned with new test outcomes.

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REPORTING: The Standard Provides Two Ways to Document the Accuracy of GPS information: 1. Test your own information set per methodology laid out in the Standard, and after that report the genuine " tried precision ", or , 2. Report the " planned precision " of your GPS in light of test outcomes distributed in the standard of the same gear utilized under comparable conditions.

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How to apply the proposed standard Reporting exactness

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1. Testing Your Own Data A definite clarification of how to test and report the precision of your GPS information set is given in the Standard and NSSDA.

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Metadata when testing your own information Report exactness at the 95% certainty level for information tried for flat precision as: Tested ____ meters/feet exactness (even) at 95% certainty level

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2. Reporting Accuracy Based on Published "Table of Tested GPS Accuracy" in the Standard This Table is a "living archive" will be overhauled with new test outcomes.

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Metadata when you utilize Table Report exactness at the 95% certainty level for information delivered by systems to follow planned even precision values as: Compiled to meet ____ meters/feet precision (flat) at 95% certainty level

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Existing FS Data Standards

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REVIEW: Four Expressions of Accuracy for the same "5 Meter" GPS information set: CEP = 5.0 meters 1s s = 6.0 meters E 90 = 9.1 meters E 95 = 10.4 meters

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Existing FS Accuracy Standards Official FS GIS Data Dictionary (Peg Watry) http://fsweb.wo.fs.fed.us/im/measures/gis/coredata/Cartographic Specifications and Symbols, EM 7140-24, Part 7, Guidelines for Digital Map Updates. (GSTC) http://fsweb.gsc.wo.fs.fed.us/principles/em714024.pdf Specify National Map Accuracy Standard (NMAS). NMAS = 90% certainty level. have reporting characteristics for Data Source however don\'t express the required certainty level. Numerous subjects Contain Optimistic assessments of GPS exactness

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FS Data Dictionary Layer: Cultural Properties ·  Heritage Resource Description A Heritage Resource is a structure, building, and so on… of noteworthy or normal criticalness, social, instructive or masterful significance, huge design attributes or a substance being overseen for uncertain safeguarding Note: A polygon ought to be utilized if GPS or other information accumulation strategies can portray the asset with more prominent precision. Flat Accuracy: Targeted to National Map Accuracy Standards (NMAS) DATA SOURCE: GPS - 2-5 Meter, 3-D study 02 GPS - 2-5 Meter, 2-D overview 03 GPS - Survey Grade and Sub-meter 04

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FS Data Dictionary Layer: Roads and Trails A scope portraying the spatial area of streets and trails inside or in close vicinity to a managerial unit. Related National Application: INFRA Travel Routes Horizontal Accuracy: Targeted to National Map Accuracy Standards (NMAS) Note GPS recieving wire DATA SOURCE: GPS - 2-5 Meter, 3-D overview 02 GPS - 2-5 Meter, 2-D study 03 GPS - Survey Grade and Sub-meter 04 No certainty level expressed.

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FS Data Dictionary Layer: Fire History Fire History polygons speak to the last mapped out of control fire border. These information are kept up at the Forest/District level to track the range influenced by flame. Spatial information is put away through a locales highlight class because of covering flame borders. Flat Accuracy: Targeted to National Map Accuracy Standards (NMAS) SOURCE_CODE: the wellspring of the geographic position of the curve 02 Global Positioning; 2 to 5 meter exactness; 3D lock 03 Global Positioning; 2 to 5 meter precision; 2D lock 04 Global Positioning; <1 meter exactness; overview review No certainty level expressed.

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Recommendations for FS existing principles Accuracy property fields of FS GIS Data Dictionaries could be overhauled to require reporting of exactness at the 95% certainty level for each NSSDA . Alter Source codes to evacuate obsolete GPS

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