If I was reading the purpose of this stackexchange site right, I could also ask general map questions. Not necessarily regarding software.

Anyways, I was wondering if someone could inform me what this blue line indicates on this topo map image. I understand the circular line with the ticks indicates a lower elevation, possible sinkhole-like, but I don't know what that blue line is.

Also, does that line with the Xs through it normally indicate a fence?

enter image description here

If it matters at all, this is a map image from an ESRI powered site.

EDIT: Here is a link http://www.kgis.org/KGISMaps/map.htm?map=topography&box=2540262:579354:2540837:579771

  • Welcome to gis.SE. Certainly non-software-specific questions are welcome here. Sometimes mapping conventions are local to an area or organisation, so if you can edit your question to add anything that might indicate the source of the original map, that might allow us to provide a better answer.
    – BradHards
    Apr 7, 2013 at 1:06
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    sorry the website the link goes to doesn't appear to be working
    – Banger
    Apr 7, 2013 at 2:26
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    Well, don't see either of those symbols in the USGS map symbols docs. Apr 7, 2013 at 2:46
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    There's a button that lets you bring up the same view in Google Maps. In satellite view there is nothing apparent on the ground that corresponds to the blue line (or the brown line with tick marks, for that matter.) As far as I can tell, the map server has no way to provide a legend, either. I'm guessing these symbols are specific to the KGIS system and represent some sort of land-use restrictions, such a pooling areas for water, though the slope of the ground makes that explanation dubious.
    – Llaves
    Apr 7, 2013 at 2:59
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    The official topo maps for the citu in which I live are made in AutoCAD and in these maps the line with the Xs is a fence. Not sure about the blue line but since this is almost certainly an AutoCAD map you might want to look at some autocad topographic symbology standards. Apr 10, 2013 at 3:07

3 Answers 3


It is. My opinion that these are flood control structures. Berms if-you-will?
Here they are used as impervious (paved) runoff holding ponds along and near water tracks.
Probably considered man made berm or control structure.

  • You are correct. I contacted them earlier and that is what it was.
    – Justin
    May 20, 2013 at 11:46

Clicking on the "legend" button on this map and scrolling reveals the line represents a "dam".



the blue line means its under water

  • 3
    Are you able to provide a reference for that, or is it just your opinion?
    – PolyGeo
    Oct 9, 2013 at 3:10

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