| Category |
Administrative/Ownership Data Base |
| Name |
.prcl_ext |
| Type |
Library Layer |
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| Abstract |
The Cadastral Base or Real Estate Atlas Program (REAP) data is comprised of two related components; Basic Parcel features consisting of current property boundaries and identifications, and Extended Parcel features consisting of historic property boundaries and additional details required in the creation of traditional Assessor Parcel maps. These related features are extremely important and provide the foundation for many subsequent GIS data layers. |
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| Maintenance |
Maintenance of City property information continues using the "Parcel Maintenance System" developed in Arc Macro Language (AML) by ITSD for use by Assessor staff. Configuration of Librarian tiles changed from Neighborhood to Section based structure in 1998 for simplication of maintenance procedures. Future plans include acquiistion of new County parcel data. |
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| Source |
Large-Scale GIS Data Base Development Part C (1995) and Update (1997) Projects |
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| Agency/Contact |
Finance Department Assessing Division / rdoletzky@ci.ann-arbor.mi.us |
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| Accuracy |
National Map Accuracy Standards for 1"=100', 1:1200, 1-2 foot positional accuracy |
| Projection |
NAD83 State Plane, Michigan South Zone 6401 |
| Units |
US Survey Feet |
| Spheroid |
GRS1980 |
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| Domain |
Quarter Sections within the Large-Scale GIS Data Base Update Project Area |
| Format |
Double Precision Link Coverage EXTD_COV; Points and Arcs with INFO attributes |
| Tiles |
167 tiles approximating Quarter Section boundaries |
| Count |
16730 Points -11758 Arcs - 8 Annotation Subclasses
| Count |
Anno Subclass |
Count |
Anno Subclass |
Count |
Anno Subclass |
Count |
Anno Subclass |
| 25017 |
ADDR |
391 |
PLACE |
97 |
NOTES |
3113 |
ROWS |
| 100588 |
DIMS |
24285 |
LOTS |
1789 |
SNAM |
85 |
VROWS |
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| Qualifications |
City Assessor and County Equalization property maps were converted for each quarter section within the Large Scale Data Base Development and Update Project Areas. Source maps were audited, and changes occurring during conversion process were trapped and integrated. The general procedure for converting the ownership information included assembling individual Assessor Blocks using "Coordinate Geometry" and registration of those individual Assessor Blocks with features identifiable on a Digital Orthophoto background. |
| Qualifications |
Accurate content and current nature of the Parcel data is now very good due to Assessor staff maintaining their own GIS data layers, while County inholding information remains static until the new County parcel data is available.
Inconsistencies can be detected regarding the symbolization of orginal lot lines and current property lines due to changes that occurred to the data base design.These inconsistencies are being corrected as time allows. |
