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how to convert page units into map unit

August 20 2009 | 0 comments
Categories: ArcGIS Methods, Cartographic Design

I have to convert the page unit into map unit.
how do i annotate a font feature class with 70 feet in arcGIS ?

Mapping Center Answer:

Assuming you are making a fairly large scale map...

  1. Convert points (1/72 inch) to the type of map unit you are using.  Sounds like you're using feet, so that would be 72 points/inch * 12 inches/foot = 864 points per foot.
  2. Multiply that by the representative fraction of your map's scale:  For example for a map scale of 1:1000 this would be:  1/1000 * 864 = 0.864 (points = 1.0 feet)
  3. Multiply the number of map units (70) by this number (0.864).  In this case that's 60.48 points.

The bad news is:  that won't work because you're using a computer.  The reason is the size of the font is based on the size of the character box as defined within the font. This accounts for descenders and additional space above the typical height of a capital letter.  Worse, this will differ from font to font.

So, pick the font you will be using.  Create rectangle feature (Advanced Editing toolbar) that is exactly 70 feet in height, and then by trial and error resize your text until it vertically fits exactly in the box.  You can decide whether that includes descenders or extra "head room".

The real lesson here is to be suspicious of anyone who tells you to, or assumes that you can, set your text size using map units.  In some cases such thinking is based on antiquated production methods (think Leroy Lettering sets).  But there are also cases where doing something like this can be purposefully applied to produce a clever or novel result.



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