Problem: Some features disappear when zoomed out but render when zoomed in
Some features on the map do not render when zoomed out but render when the user zooms in.
This is often related to generalization. Generalization is used by the Image Server to speed up the processing of features. By default, features are generalized. However, in certain cases, generalization causes some features or parts of features to drop out. This can happen with very small or narrow features. The features display when zoomed in, but as the user zooms out, part or all of an affected feature drops out. The tradeoff for not generalizing features is that the ArcIMS Spatial Server takes longer to process a request.
Solution or Workaround
In your ArcXML configuration file use the IMAGEGENERALIZATION element with mode set to false. For example:
<?xml version="1.0" encoding="UTF-8"?>
<LOCALE country="US" language="en" variant="" />
<UIFONT color="0,0,0" name="Arial" size="12" style="regular" />
<SCREEN dpi="96" />
<ENVELOPE minx="-175" miny="-85" maxx="179" maxy="85.38594439950108" name="Initial_Extent" />
<MAPUNITS units="decimal_degrees" />
<IMAGEGENERALIZATION mode="false" />