Changes between Version 3 and Version 4 of Help/Plugin/PicLayer

Timestamp:

2010-10-10T22:48:58+02:00 (15 years ago)

Author:

anonymous

Comment:

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Help/Plugin/PicLayer

@@ -36 +36 @@
 This plugin is meant to help with mapping from photos (for me it's mostly buildings) for people who simply don't like MetaCarta Rectifier.
 
+
 For those interested in converting calibration data in PicLayer:
+
 INITIAL_SCALE is the initial size of 100 image pixels (length of ruler in JOSM).
+
 SCALEX/Y is the factor after changing the size of the raster image relative to JOSM data layer.
+
 INITIAL_POS_y/X are the coordinates of the image center in mercator projection.
+
 POSITION_X/Y are the coordinates after shifting the raster image relative to JOSM data layer.
+
 ANGLE is the angle in degrees (clockwise -> positive) when the raster image is rotated.
+
 Mercator units are arc units in longitude (PI <-> 180).
+
 Latitude is a bit complicated because this projection preserves angles but not areas:
 y = ln(tan(45+b/2))
 where b is in degrees, ln ist the natural logarithm and tan ist the tangent.
+
 The longitude in degrees l is obtained from x via l = x*180/PI.
+
 The latitude b can be calculated from y by b = 2*arctan(e power y) - 45 (when inverse tangent returns degrees).
+
 When transforming longitude degree differences of image corners to distance, you have to take into account that one degree east-west has different size dependent on latitude.
+
 At equator 1 degree -> d0 = 111.3 km, at latitude b you get d = d0/cos(b)(only exact for sphere, but deviation from ellipsoid < 0.5%).