I routinely import centerlines and other data from various counties that are in different projections, so I've begun to convert everthing to WGS84 so all is in the same projection. I want to match up topology where centerlines from different counties meet, so in order to do that, I have to zoom in (really) close to see if centerline endpoints match up. However, since I've converted stuff to WGS84, when I zoom in close to features, they disappear from the display, and I can't zoom in close enough for what I need. Anyone else experience this, and is there a fix? Using ArcGIS 10.1 Advanced...


By "really close" I mean sub-centimeter at times, maybe even sub-millimeter... essentially I want to do is be able to create a network dataset so I need the lines to connect, and I need a way to identify places where they don't connect, even from small distances...

If WGS84 is not high enough precision, what would you recommend for a "universal" projection (mainly for United States) that is "high precision"? Projections have always been kind of confusing for me (as well as others I'm sure...) Thanks for your response/comments...

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    What do you mean by "really close"? My guess is that it has a function of scale. The precision of Lat/Long is not as good as something like UTM. If you are looking for sub-meter, or centimeter precision, you may want to consider switching to a different projection. – Ryan Garnett Nov 18 '13 at 22:54
  • Are you able to see this on any dataset? If so, perhaps use Create Fishnet and then describe a precise coordinate and scales at which the lines are still visible and then disappear. That would be a test we could use to try and reproduce what you are describing. – PolyGeo Nov 18 '13 at 23:09
  • See edit changes... – Jason Miller Nov 18 '13 at 23:31
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    I can think of two things: build/rebuild the spatial index or it's a display driver problem. – mkennedy Nov 19 '13 at 0:13
  • I ran my Create Fishnet test and was able to use a fishnet (polylines) stored in WGS84, projected into Mercator (World) to zoom in and measure distances of less than a micrometre almost without a problem. I say almost because occasionally the lines disappeared when I zoomed but I just hit Previous Extent and did the same zoom again and it invariably drew at the second attempt. – PolyGeo Nov 19 '13 at 5:04

Any coordinate system can be as precise as you want; it just depends on how many decimal places you work with. That is, both lat/long and UTM can provide coordinates down to the sub-centimeter level, although rarely would the data be collected down to that precision. Also, WGS84 is a datum, not really a projection such as UTM. None-the-less, your problem is not related per se to using WGS84. Projecting it wouldn't 'fix' your problem, since the projection would be based on the WGS84 coordinates. It may be related to ArcGIS parameters--what is the default precision? ArcGIS might be rounding down the coordinates; it supports both low and high precision georeferencing and you may need to explicitly set it to high precision.

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I also encountered this issue after importing AutoCAD (dwg). I noticed the problem only occurred using dotted or dashed line styles.

Changing the style of the polyline to a solid line resulted in the lines being drawn again.

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