Autor Thema: AT5.xml files - how they work  (Gelesen 3575 mal)

Offline gregory

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AT5.xml files - how they work
« am: 26 Juni 2014, 13:35:17 »
The AT5.xml format is a pretty old format that was incorporated for use in the IMC.  It was originally designed back when the HDS Gen 1's were first being released as a way to control draw over raster behavior without updating our AT5 major version.
 
The format is designed to allow users to specify the behavior of draw over raster only on polygon features.  This means that a user can set the alpha multiplier of a feature from 0 to 255 or -1 for just rendering a border and this behavior will occur over raster (or on a non-tiled unit, on the rest of the screen when only certain tiles have raster).
 
Usually, this behavior is quite simple.  You'd have something like "aCity = 100" and it was clear from the file that cities would all be rendered with a 100/255 alpha multiplier.  With the IMC, you have "a" then a bunch of gobbledygook and it makes that association very difficult because there's no clear identifier to the feature...just a feature name serialization.  On top of that, with each processed AT5 through the IMC, those feature names changed which makes it difficult or impossible to recombine these features into a single AT5.xml.
 
This was the AT5.xml's 1 major limitation.  Because several years ago, only 1 dataset was considered usable per card, the AT5.xml was considered global and placed in the root directory to affect all data on the card.  Recently, we've been working on fixing this limitation. 

As of major version 13, there is now a variable for storing this information directly in the feature definition for points, lines, and areas.  This is not implemented on the chart plotters yet but is settable through the "IMG_RENDER" attribute or the advanced options for auto generated features and set regardless of whether an AT5.xml file is exported from the IMC application.