On Fri, Nov 9, 2018 at 12:06 PM دار الآثار للنشر والتوزيع-صنعاء Dar Alathar-Yemen <hubais...@outlook.com> wrote:
> I suggest new tag to tell map render to draw the node name with a > specified rotate angle not horizontal. We need this for some seas like Red > Sea, and Suez Gulf in Egypt. > I have serious doubts whether encoding the rendering in the map in such a way is a good idea. A renderer that wished to label an area with an angled label could readily determine the angle for itself, by computing the principal axes of the area, and if its eccentricity exceeds a specified value, rotating the label to align with the major axis. An even better rendering could be achieved by computing the morphological skeleton of the area, and placing the label along some smooth curve that approximates the medial axis. There are also algorithms that handle curved label placement in the presence of interfering labels, although they are somewhat less well developed. One such is described in Mathieu BARRAULT, "A methodology for placement and evaluation of area map labels." _Computers, Environment and Urban Systems_ 25 (2001), pp. 33-52. http://geoinformatics.ntua.gr/courses/admcarto/lecture_notes/name_placement/bibliography/barrault_2001.pdf Barrault describes the process of choosing a family of circular arcs that well approximate the general contour of an area feature. Figure 3 of the paper is informative about what criteria his heuristic takes into account for 'goodness' of placement. Figures 10 and 11 show what the algorithm achieves on sample elongated figures and Figures 13-14 show what it can do in the presence of interfering labels. To place this task on the mapper forecloses on the possibility that a renderer can do it better.
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