Cadastral Framework Project Meeting Minutes
March 3, 1999
Larry Holmes, USBLM
Greg Tudor, WADNR
Wes Schlenker, Longview Fibre
Frank Fisher, WADNR
Charlie Ware, WADNR
Kevin Kozak, WADNR
Steve Kimsey, WADNR
Jeff Devitt, ARIS
Curt Kiessig, Snohomish County
Greg Tudor, Cadastral Framework Project manager, facilitated the meeting. Reviewed the minutes from the last meeting and progress on the action items. Reviewed the addition of self-integration to the Integration Process writeup.
The integration was examined within the scope of Legal Area Descriptions, Boundaries, and Corners. We reviewed the GIS technical and land survey technical situations of integrating corner information to the framework database. Additions to the database would be accepted automatically. Updates to the database would have to be checked for accuracy. If the new corner point information placed the point outside the accuracy range of the current point then a data conflict would be flagged. Data conflicts would have to be resolved between the new data provider and the old data provider. In the interest of promoting updates to the framework database, data providers would not be responsible for making adjustments to junior subdivisions and their corners. For example, if the 1/4 corner between sections 5 and 6 were moved to the NW 10 feet, the provider would not be responsible for moving the calculated 1/16th corners. However, the lines connecting the 1/4 corner to the 1/16th corners would have to be moved in order to make the network fit the corner locations. Notification of the update and the need for additional adjustment would be sent to the provider of the 1/16th subdivisions. That subdivision provider would have to determine whether they wanted to rework the subdivision adjustment at that time or wait until the adjustment fit into the scope of current work. Framework database users need to understand that junior calculated corners must be considered within the context of the original calculation and may need to be recalculated when changes to the original conditions occur.
The representation of a corner by multiple corner points was recognized as an issue. There is a business need to have these separate corner points for historical information. However, monument information is needed to distinguish the corner points from each other, but DNR and other partners do not have monument information to contribute at this time. Also, the spatial integrity of the GIS is difficult to manage with more than one representation of the corner. If a corner point is accepted as the corner in the GIS, when another corner point is found to better represent the original corner location (e.g. relocated by original accessory evidence) then the corner point must be rejected and the boundary lines related to the original corner point. The corner point is superceded by the original corner point.
While discussing the corner business rules, the business rules associated with legal description areas and boundary lines started. For corners, there is a business interest in keeping all of the corner points which could represent a corner location. For description areas, though, the business need to keep multiple representations of legal descriptions may conflict with clean ARC/INFO coverage operation. For example, a parcel may be described by the E1/2 of S5. If the section is subdivided into 1/16ths to accommodate activity in the west half, then from a business perspective the parcel description should still be the E1/2 of S5. But from a GIS network perspective, the 16ths would work better if they superceded the higher level description, e.g. NE1/4NE1/4, NWNE, SWNE, SENE, NESE, NWSE, SWSE, and SESE. The superceded description would require procedures to make the transition from the general description to the specific description parts. From an SDE perspective, the supercession of descriptions is not required since the 1/16ths can refer to their parent subdivisions, NE1/4, SE1/4, and E1/2. The parent-child relationships between 1/2s, 1/4s, 1/16ths, etc. could be very complicated by themselves.
Boundaries have similar problems. There is a business need for attributes of a description boundary to be recorded, e.g. the bearing and distance of the east line of a parcel. If the property east of the parcel is subdivided, there are now two boundaries which may need to show boundary records. However the first parcel still has a need to refer to the whole single boundary as one unit from the perspective of the legal description. Superceding the single line with two boundary lines makes the GIS spatial integrity easier to manage, but requires the business to convert the description to refer to the new boundary lines. The business must also understand the limitations of the supercession. The record distances and bearings would have to match the original. The junior status of the corner and the adjacent subdivision boundaries is not obvious.
Data Transfer Standard
The data transfer standard was explained and reviewed for content. Corrections are to be made in the overall description of the transfer standard. Fixed framework database identifiers need to be added for Legal Description Areas, Boundary Lines, and Corner Points. For the Legal Description Area transfer format, corrections are to be made to the coded values, and Area Document and Agent information are to be taken out for pre-loading and referencing them by an identifier. For the Boundary Line, corrections are to be made to the coded values, definitions/descriptions are to be added where missing, Curve information is to be taken out, and Area Document and Agent information are to be taken out for pre-loading and referencing them by an identifier. For Corner Points, corrections are to be made to the descriptions and coded values, definitions/descriptions are to be added where missing, and Area Document and Agent information are to be taken out for pre-loading and referencing them by an identifier.
1. Complete the data transfer standard and specifications for Corner, Boundary, and Legal Area Description. Distribute in PDF format via e-mail and web site - Greg Tudor.
2. Illustrate specific examples of database adds and updates - Greg Tudor
3. Review the impact of adding framework identifiers to features in proprietary databases - BLM, Snohomish County, Longview Fibre.
April 7, 1999