(3) Digital BAS Training (Jan 2012)
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(3) Digital BAS Training (Jan 2012)



2012 Boundary and Annexation Survey (BAS) training by Census. Training sponsored by WVAGP.

2012 Boundary and Annexation Survey (BAS) training by Census. Training sponsored by WVAGP.



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  • Explain why there are two lines – moved boundary to correct location
  • Username is ‘BAS’.
  • Last bullet point - If you only remember 1 thing from this presentation, make it this (snap to existing census geography whenever possible)!
  • Make sure you return your .prj file to us (or metadata containing your projection info if your GIS doesn’t produce a .prj file).
  • Linear features: Streets, rivers, etc. Point landmarks: airports, mountain peaks Area landmarks: parks, lakes/water features, etc. Address ranges: these do not show actual addresses – merely a range of potential addresses.
  • Describe what to put in each field. We also request that they provide us with the area being annexed/deannexed. It is required in Georgia.
  • Bullet point#1 - This is important for some cities because they are portraying that the city is not responsible for road maintenance. This is NOT relevant for the Census Bureau tabulations and is not easy to depict in our nationwide database. This type of corridor should NOT be included in your BAS response.
  • Again, without additional information, the census bureau will code the addresses to the centerline of the road. While the census bureau recognizes that most local governments do use parcels to map their boundaries, the census bureau would ultimately prefer that participants use the centerlines to map their boundaries. This ensures that the correct population counts are assigned to the correct geographies….etc etc.
  • We strongly request you don’t do reshapes.

(3) Digital BAS Training (Jan 2012) Presentation Transcript

  • 1. Introduction to the Digital BAS
  • 2. Overview
    • What is the MAF/TIGER Database?
    • What is included in the Digital BAS package?
    • What is the difference between Digital BAS and MTPS?
    • What are some tips for updating the BAS materials digitally?
    • How do I return my digital submission to the Census Bureau?
    • MTPS and Digital BAS Demo
  • 3. MAF/TIGER Database
    • Master Address File/Topologically Integrated Geographic Encoding and Referencing ( MAF/TIGER Database )
    • Rather than having one layer for each feature class, all information is stored in a single layer
    • Database is constructed of nodes, edges, and faces
    • Each edge can represent the boundary for multiple geographies:
      • Place, County, Tract, School District, Voting District Boundaries, etc.
    • Changing a place boundary can affect boundaries for other geographies
  • 4. Topological Relationship Census Tract Edges Incorporated Place Integrated Layer School District
  • 5. MAF/TIGER Database - Edges
  • 6. MAF/TIGER Database – County Subdivisions
  • 7. MAF/TIGER Database – School Districts
  • 8. MAF/TIGER Database – Voting Districts
  • 9.
    • Letter and Form
      • Contains your username for MTPS: bas
      • You do not need to fill out the form when responding digitally
    • MAF/TIGER Partnership Software CD
    • Data and Respondent Guide CD/DVD
      • Contains shapefiles for use with Digital BAS and MTPS
      • Contains respondent guides for Digital BAS and MTPS
    • No Change postcard
    BAS Package Materials
  • 10.
    • Participants use their own GIS to create the digital BAS submission file:
      • Create change polygons representing the difference between local boundaries and the Census Bureau’s boundaries
      • Attribute each polygon with the required information
    • We send out ESRI shapefiles (.shp), but any GIS that can read/convert shapefiles may be used
    • It is important to read the Digital BAS respondent guide carefully to make sure you include all required information
    Digital BAS
  • 11.
    • As an alternative to another GIS software, participants may use the Census Bureau’s free MTPS to create the digital BAS submission file.
    • The MTPS forces the user to include the required attribute information for the boundary and feature updates.
    • The software handles the data conversion and compresses all of the output files together for you to create the final digital BAS submission file.
    • MTPS is appropriate for users who are not experienced in GIS or do not have their own GIS software.
    MAF/TIGER Partnership Software - MTPS
  • 12.
    • We cannot accept a local GIS file to “replace” our existing boundary information:
      • Must have legal documentation and effective dates for all legal boundary changes
      • We must keep record of all changes made for reference purposes
      • Topologically integrated database
    • Snap to existing census geography where appropriate:
      • Use existing census roads, rail, and hydro wherever possible (if our river and your river differ spatially by 10 feet, snap to our river)
    Digital Update Guidelines
  • 13.
    • Census files are in GCS NAD 83 format and can be projected into any local coordinate/projection
    • Most GIS software packages will allow users to transform file coordinate systems and projections
      • In ArcGIS, use the Project tool in ArcToolbox
    Data Projections
  • 14.
    • Annexations & Deannexations
    • Boundary Corrections
    • Geographic Corridors & Offsets
    • New Incorporations
    Types of Boundary Updates
  • 15.
    • Linear Features
    • Point Landmarks
    • Area Landmarks
    • Address Ranges
    Other Acceptable Updates
  • 16.
    • These are referred to as legal boundary changes :
      • Large change polygons are most likely annexations
      • Change polygons are sometimes not contiguous with your boundaries
      • A change to the entity’s boundary through a legal action:
        • Ordinance/Resolution
        • Local law or Court order
        • State level action
      • Must always include the following in lieu of the actual legal documentation:
      • Effective Date
      • Ordinance/Resolution Number
      • Acreage required for Georgia entities
    Annexations and Deannexations
  • 17.
    • Must enter the following in the change polygon attribute table for each annexation/deannexation:
      • Name of the affected entity
      • The effective date
      • The document/authorization number (Ex: ordinance or resolution #)
    • Change type is coded A for annexation or D for deannexation
    Annexations and Deannexations (Attribute Table)
  • 18.
    • Minor fixes to the entity boundaries due to drafting or plotting errors.
    • Should follow the general shape of the current boundary.
    • Are neither annexations nor deannexations, although they may be fixing the depiction of previous annexations or deannexations.
    • Boundary corrections DO NOT require legal documentation.
    Boundary Corrections
  • 19.
    • Must enter the name of the affected entity in the Name field
    • Enter “B” in the Change Type field to designate a Boundary Correction
    • In the Relate field enter the following:
      • IN if the territory needs to be in the affected entity
      • OUT if the territory needs to be out of the affected entity
    Boundary Corrections (Attribute Table)
  • 20.
    • An area that only includes road surface and right-of-way and does not contain any structures addressed to either side of the road.
    • The Census Bureau will geocode addresses based on the centerline of road.
    • There are two types of geographic corridors
      • 1.) Road through unincorporated space
      • 2.) Road through incorporated space
    • BAS participants should recommend the creation of a geographic corridor ONLY when this coding would result in addresses being assigned to the wrong entity.
    Geographic Corridors
  • 21. Example: Road through an unincorporated place In this example, the houses are in unincorporated county, while the road ROW has been annexed into an incorporated place. Without a corridor, the housing units along this road would be included in the incorporated place. Geographic Corridors
  • 22.
    • An area claimed by an entity that is only on one side of the road and does not include any structures addressed to the right-of-way on that side of the road.
    • Policy towards Geographic Offsets:
      • We prefer that you do not show a boundary on a front lot line.
      • If houses on the far side of the road should be in your jurisdiction, please represent the boundary on the rear lot line.
      • If houses on the far side of the road should NOT be in your jurisdiction, please snap the boundary to the centerline.
    • An offset should be used if you must show the boundary on the front lot line.
    • Using one of these techniques insures that the residential structures will be assigned to the correct geography.
    Geographic Offset
  • 23. We prefer that you snap the boundary to the centerline as offsets are difficult to maintain. If offsets are not coded as such, your boundary will be snapped. Geographic Corridors and Offsets Incorporated Places A B
  • 24.
    • For all new incorporations, we need the following:
      • The official name of the new incorporation
      • The name and phone number of a contact person for processing
      • A copy of the official papers of incorporation
      • The effective date
      • The mailing address
      • The name of the HEO of the new incorporation
      • The name of the BAS contact of the incorporation, if different from the HEO
    New Incorporations
  • 25.
    • Street features can be added or edited in MTPS or ArcGIS
    • These are not required unless they serve as a boundary
    Street Features
  • 26. Data Dictionary
  • 27.
    • Compress your change polygon shapefile and any other edited shapefiles into a zip file
    • If you are using MTPS , the software will automatically zip the required shapefiles after you are done.
    • Upload the zip file onto the Census Bureau’s FTP site.
      • Instructions for the site are provided in the Respondent Guides.
    • The MTPS submission file can be quite large. If you are having issues uploading the file onto the FTP site, simply remove all the files that do not contain the BAS prefix in the name, and try uploading again.
    Reporting the Data to the BAS
  • 28. Digital BAS Demonstration ArcGIS & MAF/TIGER Partnership Software (MTPS)