VEP VALIDATION GUIDE 

The DATAMARK team has created this guide to help the client review, understand, and begin to resolve anomalies produced by DATAMARK VEP’s suite of Validation checks. Efforts should be taken to address and correct validation anomalies. The goal should be to get the number of anomalies down to zero. At times, exceptions to the rules will occur. Mark ‘Exceptions’ as necessary. Please note the proposed workflow is holistic and every component may not apply - it is dependent on what stage the client is in the editing process. 

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VEP VALIDATION PROPOSED WORKFLOW 

  • Boundary layer topology 

  • Population of mandatory fields; mass calculations of fields; standardizing field values between datasets 

  • Road Centerline topology 

  • Road Centerline ranges 

  • Address Point anomalies and Fishbone Analysis related validations 

  • MSAG/ALI anomalies 

  • ‘Exception’ management 

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VALIDATION BREAKDOWN 

The suggested order of resolving anomalies is as follows: 

  • Resolve Boundary Validation Anomalies 

    • Gaps and Overlaps in PSAP Boundary 

    • Gaps and Overlaps in Emergency Service Boundaries (Law, Fire, EMS) 

    • Island Topology Errors 

    • Boundary is Multipart 

    • Boundary is Multipart and an Island 

  • Rerun VEP Validations 

    • Rerun VEP validations after new boundary layers are created and updated 

  • Resolve Feature Attribution Anomalies 

    • AP/RCL missing attribution 

    • Missing mandatory field values 

      • Discrepancy Agency ID, Country, State, County, Incorporated Municipality, etc. 

    • AP not reflected in RCL – utilizes fishbone logic 

      • Standardizing of street attributes (e.g., Parse and format pre-directionals, street pre-types, street post types, post directionals) 

      • Prioritize bulk standardization up front to allow a relationship between AP and RCL to be identified. This allows for fishbones to draw. 

      • Note: If an AP Not Reflected anomaly is flagged, no proper relationship between AP/RCL is found, which prevents fishbones from drawing. If fishbones do not draw, this prevents other anomalies that utilize fishbones from flagging; AP Maps to Multiple, AP Misordered Along RCL. 

  • Resolve RCL topology validations 

    • RCL topology validations 

      • RCL Intersecting 

      • RCL Overshoot/Undershoot 

      • RCL Multipart 

      • RCL Self-intersecting 

      • RCL is Too Short 

      • RCL Too Close 

      • RCL Digitized Direction 

    • If RCL intersects, be sure to update the ranges of the split segment to avoid creating additional anomalies 

  • Resolve Boundary/RCL relationship anomalies 

    • RCL not snapped to boundary 

    • RCL not split along boundary 

    • RCL not snapped to RCL on boundary 

  • Resolve Road Centerline range anomalies 

    • RCL Range Inconsistency 

    • RCL Range Incomplete 

    • Correct overlapping RCL ranges 

      • Also resolves ‘AP maps to Multiple’ and ‘AP Misordered’ anomalies 

  • Rerun VEP Validations 

    • Rerun VEP validations after attribute updates and road centerline topology updates 

  • Resolve AP Anomalies and all others remaining 

    • Identify and fix duplicate address points 

      • Typically, due to a lack of sub-address values 

    • Revisit AP not reflected in RCL anomalies 

      • At this stage, those that are remaining should be true discrepancies between AP/RCL 

    • AP mis-ordered along RCL – uses fishbone logic 

    • Boundary/feature contained validation anomalies 

      • RCL Not Contained Within Boundary 

      • AP Not Contained Within Boundary 

    • RCL Parity Inconsistency – mass calculation upfront 

      • Recalculate parity values in bulk as the editor goes through phases of editing 

      • Calculate in data prep before re-uploading into VEP 

  • Resolve MSAG/ALI Validation Anomalies 

    • MSAG and ALI anomalies help identify where there are discrepancies between RCL/MSAG and AP/ALI 

    • Do this after GIS layers have been remediated to produce the true discrepancies between GIS layers and Legacy tables 

Rerun VEP validations and continue to iteratively work through the correction of anomalies.   

VEP Validations can be run at any point throughout the above process to see how the data is progressing through updates. Consider this iterative workflow as a form of QC. Repeat the above steps as necessary. 

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COMMON ‘EXCEPTION’ MARKED ANOMALIES (VEP) 

  • AP Misordered Along RCL 

    • Long driveways/large parcels 

    • Placement of buildings 

    • Curvature of the road in relation to full road range 

  • AP Not Reflected – Wrong Side 

  • RCL Digitized Direction 

    • Increasing APs on one side and decreasing on the other 

    • Endpoints/Startpoints meet but represent associated APs 

  • RCL Intersecting 

    • Highway overpass/underpass most common 

  • RCL Self-Intersecting 

    • Highway on-ramp where it loops around 

  • RCL Too Short 

    • “Connector” segments between street intersections 

  • RCL Too Close 

    • e.g., A highway on-ramp that mostly parallels the highway before splitting off 

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RESOURCES 

DATAMARK VEP Support Center 

NG9-1-1 Standards and Resources