This chart shows the final organized opinion of the community in regard to the relative value of ac cessibility of standard lots. This relation is expressed in the following manner : the most valuable block frontage in the city is chosen, and the value at that point is designated as 100; the values of all other block frontages are then indicated as percentages of this sum. When the accessibility of a standard in side lot has been determined for each block frontage, it is a comparatively simple matter to estimate the actual value of any lot by allowing for depth greater or less than the standard, for corner influence, for plottage value, and for the cost of filling or excavat ing to bring the ground to the street level.
7. Variation of value with authorita tive rules are used in the valuation of depth. One of these was formulated by William E. Davies after an examination of the records of the sale of 10,200 par cels of land of different sizes and shapes in New York City. The complete Davies rule, giving the values for each foot of depth up to 200 feet, is to be found in the Annual Manual and Diary of the Real Estate Board of Brokers of New York City. The other rule is that of the Somers System. This rule in its complete form—also applicable to lots as deep as 200 feet—appears in a free pamphlet distributed by the Manufacturers' Appraisal Company of Cleve land. The quantities given in the comparative table,' are percentages of the value of a standard lot which has the same properties as the lot to be measured, but which is 100 feet in depth.
There are two older rules for depth. The first is known as the Hoffman rule. It gives lower values than the Davies rule, up to 50 feet, and higher values from 50 to 100 feet. The second is the Neill rule, which gives higher values than the Davies rule up• to 50 feet, and lower values for greater depths. The rule that is most convenient to remember is that of George J. Craigen. It reads as follows: Where 100 feet in depth is worth a given price, take for each 25 feet from front to rear, 40 per cent, 30 per cent, 20 per cent, 10 per cent, 9 per cent, 8 per cent, '7 per cent, 6 per cent ; a total of 130 per cent for a lot 200 feet deep.
8. Corner influence.—The ground at or near the intersection of two streets possesses a greater value than inside lots, because a building erected upon it will have more light and air, and the business will possess superior transportation advantages and will make a stronger appeal to the passing public. This enhancement of value, above what is normal for nearby inside lots, is obviously greatest where two prominent streets of equal importance intersect. As the streets become less important and more unequal in importance, the enhancement of values in corner lots decreases. The Commissioner of Taxes and Assess ments of New York City gives the outside limits of enhancement, as follows : In a suburban section where the appropriate development is by the erection of detached houses, the appreciation be cause of corner position may not be more than 25 per cent for a lot 25 x 100; on the other hand, when the lot is at the corner of two streets, both of which are good retail shopping streets, the increment of value of a lot 25 x 100 may be more than 200 per cent over the value of an adjacent interior lot.
The appropriate increment of value due to corner position must be considered with reference to the actual earning power and consequent selling value of corner lots in the par ticular section. The distance from a corner to which the influence upon value of proximity to the corner extends, depends upon the character of development appropriate for the neighborhood. Where a lot 100 feet square is the ap propriate size for a building, the corner influence extends to the whole 100 feet ; on the other hand, where a vacant plot 100 feet square at a corner would be improved with four or more buildings, the corner influence extends no farther than the width of the first lot.
The Somers System of valuation provides a series of corner-influence tables, giving the enhancement for the parts of an area 100 x 100 feet for every pos sible combination of street-unit values on the adjacent sides of the block. A street-unit value is the value of a strip of land, one foot wide by 100 feet deep, which is free from corner influence. Figure 2, page 51 represents one of these tables; it gives the values where a street with $1,000 unit value is intersected by a street with $250 unit value.
9. value is the additional value which is possessed by a plot of ground composed of a group of lots, and desired for a use that demands unit areas larger than a single lot. This element of value is well described by the Commissioner of Taxes and Assessments of New York City, in his report for 1914, as follows: Where the appropriate improvement of a section demands lots of standard size, a lot of greater width than standard size has no more relative value than a lot of standard size, but where the appropriate building for that section requires a plot of greater depth, the larger plot has a greater rela tive value than the standard lot. In such cases an appro priate addition must be made to the value above that in dicated by the unit, according to the size of the particular lot to be valued. In a tenement house section in Manhattan, a lot 37Y2 feet wide is worth relatively more than a lot 25 feet wide, because a tenement house, under the law, cannot profitably be built on a lot 25 feet wide, whereas an eco nomical tenement house can be erected on a lot 37% feet wide. In a territory suitable for lofts, a lot 50 feet wide is worth more than twice as much as a lot 25 feet wide, and generally a lot 100 feet wide would be worth more than twice as much as a lot 50 feet wide. The appropriate increase for plottage must be considered with reference to the actual con ditions prevailing in the section where the lot is situated. An addition for plottage may be as great as 20 per cent, or even more.