臺灣地區地形圖係採橫麥卡托投影製圖，從早期的六度分帶到目前二度分帶，中央經線的尺度比值由0.9996調整爲0.9999，具體的影響就是長度最大變形誤差，由1/2,500降至1/10,000，使之更符合地籍測量精度的要求。由於長度變形係受投影結構影響所造成，無法藉由儀器或測量方法得到改善。基此，要提升測圖精度，改善投影結構則爲重要關鍵。爲因應高土地利用之精度要求，以目前我國地形圖所採用之二度分帶橫麥卡托投影，中央經線的尺度比值k0=0.9999是否合適，木文將綜合考量臺灣本島各主要市鎮分布的位置，配合行政區劃等級給權，重新計算中央經線尺度比值，除了能具體改善臺灣地區長度變形影響外，對測圖精度的提升是最根本且有效的方法。
Transverse Mercator Projection are often used to make topographic maps in Taiwan. From 6 degree zone in early stage to current 2 degree zone scale at the central meridian is changed from 0.9996 to 0.9999. The obvious effective influence is to decrease the maximum distortion errors from 1/25,00 to 1/10,000 in order to match the accurate requirement of cadastral surveying. Due to the distance distortion is affected by the structure of the projection, the errors can not be reduced by adjustment of instruments or the methods of surveying. Based on this, it is crucial to improve the structure of the projection if the accuracy of mapping is going to be dealing with. In consideration of the high accuracy requirements from land use aspect this research will recalculate a new scale factor to replace the k0 (k0=0.9999) by giving weighs of administrative district ranks with the consideration of the locations of cities in Taiwan. Not only can this research crucially and effectively reduce the influence of distance distortion but also promote the accuracy of mapping.
