Measuring lenghts and area, which coordinate system/datum is best?

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07-29-2016 02:29 PM
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LukePettinga
New Contributor

I would like to have a discussion regarding which coordinate system(s) are best, and/or are typically used, for measuring both the lengths and areas of mapped features at various scales, and addressing the specific limitations/cautions/concerns that arise from using any single coordinate system for this type of work.

This can range from the simple (ex., geographic vs. projected coordinate system (GCS vs. PCS) to measure area, or selecting an appropriate datum) to the more advanced (ex., when it is appropriate to use (or not use) a projected UTM coordinate system).

Impetus: I need to measure both lengths and areas of objects on the scale of 10s to 100s of km across that are located in areas distributed around the globe. In pursuit of developing a simple, efficient, and accurate workflow: I would like to minimize the number of coordinate systems (and conversions between them) that I will need to us to obtain accurate length and area measurements. Is there a single coordinate system that I can use to accurately measure both? Or, will I need to use multiple? What coordinate system(s) are best for this work, and what are their limitations? etc.

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DanPatterson_Retired
MVP Emeritus

In some cases it is best to read the tool's help... for example

  Generate Near Table—Help | ArcGIS for Desktop  for long distances geodesic would be best

large areas would be a challenge, but you probably wouldn't be expecting extremely accurate results in any event.

I tend to use UTM if EW spacing is less than 6 degrees, a MTM (modified Transverse mercator) for EW spacing less than 3 degrees and a Lambert conformal conic for EW distance greater than this and for latitudes > 45 N... maybe a little Albers South of this.

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