arcgis data reviewer: assessing positional...

ArcGIS Data Reviewer:Assessing Positional Accuracy

Roslyn Dunn

What is ArcGIS Data Reviewer?Data Quality Management for ArcGIS

• Provides- Rule-based validation- Interactive tools- Track errors

• For individuals and enterprise- Saves time/money- Less rework

• For multiple domains- Configurable- Extendable

EnterpriseWorkflow

Validate

ReviewSummarize

ArcGIS Data Reviewer: Assessing Positional Accuracy

What is ArcGIS Data Reviewer?Data quality management in the ArcGIS platform

• Data Reviewer for Desktop- ArcMap- ArcGIS Pro

• Data Reviewer for Server- Standard or higher

• Data Reviewer API- JavaScript- FLEX

• Web AppBuilder for ArcGIS

Server

Online Content and Services

Desktop Web Device

ArcGIS OnlinePortal


• Spatial (position, geometry, topology)

• Attributional (correctness of attributes)

• Spectral (band depth)

• Temporal (appropriate date)

• Radiometric (capture piece of electromagnetic spectrum)

ArcGIS Data Reviewer: Assessing Positional AccuracyForms of Geospatial Data Accuracy


• Data needs to be in the “right” place for intended purpose

- Usually scale-dependent to some degree

• All else being equal, less accurate is less valuable

• Data products usually need to conform to a specification

- ASPRS Positional Accuracy Standards November 2014

- Orthoimagery

- Digital Planimetric Data

- Digital Elevation Data

• DMA - Error Theory as Applied to Mapping, Charting, and Geodesy

ArcGIS Data Reviewer: Assessing Positional AccuracyConcepts


http://www.asprs.org/wp-content/uploads/2015/01/ASPRS_Positional_Accuracy_Standards_Edition1_Version100_November2014.pdf

http://earth-info.nga.mil/GandG/publications/tr8400_1.pdf

• Accuracy

- The closeness of the best estimated value obtained by the

measurements to the “true” value of the quantity measured

- How well does the measured quantity compare to the “true” value?

• Positional Accuracy

- The Quantifiable value that represents the positional difference between two

geospatial layers or between a geospatial layer and reality

• Circular Error (CE) is an error measurement for both X & Y

• Linear Error (LE) is generally an error measurement for Z (elevation)

• RMSE is a statistical measurement of the variance between the residual values

ArcGIS Data Reviewer: Assessing Positional AccuracyDefinition of Terms


• Circular Error – a two-dimensional error measure (X, Y)

• CE 90, 95, 99

- The radial error which n% of all errors in a circular distribution will not exceed

- Circular error at n% confidence level

- e.g. If CE 90 = 2.0 Meters

then we are 90% confident that the measurement

lies somewhere within a circle with a radius of 2.0 Meters

i.e. we’re 90% sure the error won’t be more than 2.0 Meters



• Linear Error – a one-dimensional error measure (z)

- A measure of the vertical accuracy of the terrain (e.g. DEM or TIN)

• The difference between the true or known value and the measured or derived value

• LE 90, 95, 99

- Linear error at n% confidence level

- e.g. If LE 95 = 10 Meters

then we are 95% confident that the “true”

elevation measurement is within 10 Meters


25

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ELEV

ATIO

N (M

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• PAAT Tool - Part of GIS Data Reviewer

• Created with requirements gathered from NGA

• Determine accuracy of

- Imagery

- Rasters

- Vectors

ArcGIS Data Reviewer: Assessing Positional AccuracyPositional Accuracy Assessment Tool (PAAT)


• NGA standard or USGS standard

• CE 90, 95, 99

• LE 90, 95, 99 (for DEMs or TINs)

• RMSE

• Absolute or relative

ArcGIS Data Reviewer: Assessing Positional AccuracyPositional Accuracy Assessment Tool (PAAT) Reporting


• Text report

• Optional outputs:

- Accuracy attribute populated

(if assessing vectors)

- XML Metadata

- ISO

- PMAA (NGA)

- Shapefile of point reading locations

ArcGIS Data Reviewer: Assessing Positional AccuracyPositional Accuracy Assessment Tool (PAAT) Outputs


Positional Accuracy Assessment Tool(PAAT)

DEMO


• Time is money

• Sampling saves time

• Statistical sampling tool

answers the question:

“Given a population size, what

sample size do I need to be X

percent confident that the

sample size is statistically

significant, within Y percent

margin of error?”

ArcGIS Data Reviewer: Assessing Positional AccuracyPositional Accuracy Assessment Tool (PAAT) Statistical Sampling


Want to learn more?

• Product informationwww.esri.com/datareviewer


Want to learn more?

• Documentation- Desktop- Server

• Training (training.esri.com)- Assessing Data Quality using ArcGIS Data Reviewer (Seminar)- Evaluating Positional Accuracy Using ArcGIS Data Reviewer for Desktop (Seminar)- Data QC with ArcGIS: Automating Validation (Web Course)- Data QC with ArcGIS: Visual Review (Web Course)- Quality Control Using ArcGIS Data Reviewer for Desktop (Instructor-Led)


Day and Description Type Time Location

Tuesday June 28

ArcGIS Data Reviewer: An Introduction Technical Workshop 8:30 – 9:45am Room 15B

ArcGIS Data Reviewer: Assessing Positional Accuracy Demo Theater 10:30 – 11:15am Demo Theater 4Geodata

ArcGIS Data Reviewer: Integrating ArcGIS Data Reviewer and ArcGIS Workflow Manager to Automate Data Quality Control Workflows

Demo Theater 11:30 – 12:15pm Demo Theater 4Geodata

ArcGIS Data Reviewer: Leveraging Geoprocessing for Data Validation Demo Theater 12:30 – 1:15pm Demo Theater 4

Geodata

ArcGIS Data Reviewer: Quality Assessment for Elevation Raster Datasets Demo Theater 2:30 – 3:15pm Demo Theater 4

Geodata

Wednesday June 29

ArcGIS Data Reviewer: An Introduction Technical Workshop 3:15 – 4:30pm Sapphire Ballroom

A/B

Thursday June 30

ArcGIS Data Reviewer: Advanced Data Validation Concepts Technical Workshop 8:30 – 9:45am Room 32 A/B

ArcGIS Data Reviewer: Implementing Data Quality Reporting in Web Clients Demo Theater 10:30 – 11:15am Demo Theater 6

Server

ArcGIS Data Reviewer: Integrating Data Validation Capabilities into Web Applications Demo Theater 12:30 – 1:15pm Demo Theater 6

Server

Want to learn more this week?


Thank you…

• Please fill out the session survey using the Esri Events mobile app

• Select “ArcGIS Data Reviewer: Assessing Positional Accuracy” session

- Use the Search Feature to quickly find this title

• Scroll-down to the “Feedback” section• Answer a few short questions, enter any comments and

select “Submit”!


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