Re: [Shapedotnet-development] Layer Visibility Range

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Layer visibility thresholds became a hot topic with a previous project
I was a part of.&nbsp; The trouble is, what units of measurement do you use
to toggle a layers visibility?&nbsp; I see that you're using a percentage in
your example, but is that a percentage of the viewport as compared to
extents of the map, or the map layer?&nbsp; While we're considering it, is
that a percentage of area coverage or a percentage of total map
features, or a percentage of layer features?&nbsp; Area will probably
provide the least performance hit to calculate, but then you run into
the issue of one layer being in a lat/lon format and a second layer in
the map being projected in feet or meters or...<br>
<br>
I think trying&nbsp; to make this work at the GIS namespace level is a
recipe for headaches, it's too application specific.&nbsp; Best to provide
some sort of metric that represents the current "zoom level" or scale
as a property of the Map object and let the application developer
determine how to handle it.&nbsp; We could even go one step further and
raise a custom event like OnScaleChange or some such.<br>
<br>
I know this looks like a simple issue, but I've been bit before and I
could never get the solution generic enough to work correctly in all
situations.&nbsp; Of course I don't claim to be the sharpest pencil in the
drawer and I never say never, someone else may have a workable generic
solution.&nbsp; I love reading code.&nbsp; :)<br>
<br>
John<br>
<br>
Rife, Ryan wrote:<br>
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  <p class="MsoNormal"><font size="2" face="Arial"><span
 style="font-size: 10pt; font-family: Arial;">I&#8217;m not sure if this
needs to be part of SDN or the
parent application or if it already exists, but the application I am
working
needs to be able to set the layer&#8217;s visibility based on far in the user
has zoomed into the map.&nbsp; For example if a layer could have a
visibility range
of 20%-50% so when 50% or less of the map is visible then the layer is
automatically turned on&#8230;.if the map is only 20% visible or goes more
than
50% visible then the layer would automatically turn off.&nbsp; Later.<o:p></o:p></span></font></p>
  <p class="MsoNormal"><font size="2" face="Arial"><span
 style="font-size: 10pt; font-family: Arial;"><o:p>&nbsp;</o:p></span></font></p>
  <p class="MsoNormal"><font size="2" face="Arial"><span
 style="font-size: 10pt; font-family: Arial;">Ryan Rife<o:p></o:p></span></font></p>
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