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
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional 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
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional AccuracyDefinition of Terms
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional AccuracyDefinition of Terms
25
0
5
10
15
20
25
30
35
40
45
ELEV
ATIO
N (M
)
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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)
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional Accuracy
Positional Accuracy Assessment Tool(PAAT)
DEMO
ArcGIS Data Reviewer: Assessing Positional Accuracy
• 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
ArcGIS Data Reviewer: Assessing Positional Accuracy
Want to learn more?
• Product informationwww.esri.com/datareviewer
ArcGIS Data Reviewer: Assessing Positional Accuracy
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)
ArcGIS Data Reviewer: Assessing Positional Accuracy
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?
ArcGIS Data Reviewer: Assessing Positional Accuracy
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”!
ArcGIS Data Reviewer: Assessing Positional Accuracy
ArcGIS Data Reviewer: Assessing Positional Accuracy