Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. The base scale for all size values that will be given in points
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1 point = 0.35146 mm. Each text object has a font size from the style. To enable annotation text, a mechanism is needed whereby text may be defined in points but usually based on a
specific map scale. Thus, a text object would be placed using a font size of 24 point at 1:1000000 and client-rendering engines would use this information to scale the text size appropriate to changes in the map scale. This base scale would be
stored once in the metadata. Any point size values in the metadata attributes column see below or in individual rows would be relative to this value, as would letter-spacing and word-spacing, stroke-width for text and leader line and both vertical
and horizontal margins. Application may round to the nearest point during scaling.
6.1.6.2 Table or View Constructs for structural metadata
The following CREATE TABLE statement creates an appropriately structured table to be included in the schema, describing how text is stored in a feature table. This should be either an actual metadata table or an updateable
view so that insertion of reference system information can be done directly with SQL.
Note that there is no requirement that the annotated feature have any other attributes. Unattributed annotations are in essence context-free, and may be used to place any text on the data, such as collection metadata or notes
to user about unusual situations of which he may wish to be aware.
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Th e r e i s s o m e m i n o r d i s a g r e e m e n t o n t h e s ta n d a r d f o r a t e x t p o i n t . Th e U S - U K s ta n d a r d i s 1 7 2 . 2 7 i n c h , A d o b e P o s ts c r i p t u s e 1 7 2
i n c h . Tr a d i t i o n a l t y p e s e t t e r s u s e 1 6 4 i n c h a n d E u r o p e a n b a s e d o n a F r e n c h s ta n d a r d u s e a p p r o xi m a t e l y 1 6 7
i n c h . A t t h e s i z e s o f n o r m a l t e xt a t n o r m a l d i s p l a y s c a l e , n o n e o f t h e s e d i ff e r e n c e s a r e s i g n i f i c a n t . Th e s e m a n o r d i ff e r e n c e s m a n m a k e f i n e s c a l e c o m par i s o n
o f o u t p u t d i ff i c u l t t o m a k e .
