Mr. Erik Berg-Johansen <br />August 14, 2015 <br />Page 6 <br />As shown in the figure on the following page, this offset is caused by the fact that in the western <br />portion of the diagram, the applicant has moved the tax lot, city limits, UGB, and road centerline <br />layers 179 feet to the northwest (N 58°W) relative to the equivalent position on the maps as <br />supplied by LCOG. In the eastern portion, the offset direction is more northerly due to the effect of <br />the 2-degree rotation. The following figures show a sequence of overlays of different transparency <br />(0% - 50% -100%) of versions of the Tax-Lot-Layer-on-Metro-Plan-Diagram obtained from LCOG <br />vs. the applicant's version on their sheet ZC-4. <br />In light of these obvious differences, the question that must be answered which map version is <br />correct, or, more precisely, more correct. Even if the rotation issue is ignored, the Schirmer-Satre <br />version of the tax lot overlay onto the Metro Plan Diagram is clearly significantly different (by 179 <br />feet) from that used by LCOG and the City. However, simply the fact that LCOG's version has <br />been used for some time now does not necessarily imply that it represents the "best" or "correct" <br />way of overlaying the tax lot layer onto the Metro Plan diagram. <br />Mr. Clingman at LCOG was again contacted in order to shed light onto this question. His email <br />response covering the issue is attached. In short, the relationship of the tax lot maps to the State <br />Plane Coordinate system is most precisely defined in the GIS system because property boundaries <br />are the most precisely surveyed. Similarly the City Limits layer of the GIS system can be aligned <br />with the tax lot layer and State Plane Coordinate System relatively well because annexations are <br />typically performed based on surveyed boundaries. However, where not defined by surveyed <br />boundaries, the UGB has a less precise alignment to the tax lot layer than the City Limits. <br />Similarly, the Metro Plan Zoning Designation layer, where boundaries are not defined by surveys, <br />but by lines drawn on paper, is less precisely aligned to the tax lot map and State Plane <br />Coordinate System than other layers. <br />The question then is how much "slop" is present in the relationship between the Metro Plan <br />Diagram and the tax lot layer? <br />Schirmer-Satre uses a very small "snippet" of the Metro Plan diagram in isolation, in order to <br />perform the alignment using only two referents (30th Avenue R-o-W centerline and north arrow). <br />LCOG uses the entire diagram. <br />According to the tax lot map (Lane Co Map 18030900), in the vicinity of the Laurel Ridge property, <br />the width of the right-of-way for 30th Avenue varies from 240 to more than 300 feet (there are even <br />wider R-o-Ws in the area of the Spring Boulevard interchange). This is, comparatively, a very <br />large right-of-way and poorly defines the actual location of the road. As a result, use of this <br />referent imparts a very large measure of "slop" into the alignment of the diagram with the tax lot <br />layer. In addition, in this area, the road surface itself is located close to the western boundary of <br />the R-o-W as the eastern portion of the R-o-W is taken up by road embankments. Aligning the <br />centerline of the R-o-W with the center of the road moves the R-o-W centerline significantly farther <br />west than it is located in reality. <br />