I know my question does not have an exact answer (it will depend on the region of the globe we're talking about), but I wanted to know what's the overlap between two UTM zones? Centimeters, meters, hundreds of meters? The same question applies for different latitude bands.
I'll localize a robot in region close to the intersection of two zones and two bands (therefore I might be in 4 different zones) and would rather force the Lat/Long-to-UTM conversion to always use the same zone. I know the further I get from the meridian the less precise it will be, but what's an acceptable distance I could cross from a zone and still force it to project it into another zone? Again, I just need want to know an order of magnitude. If I get some 100 kilometers out from one zone into another, what's the magnitude of the error I should expect?
If anyone has any references on where I could go about calculating all these more precisely, I'd appreciate.
I think I see what you've driving at: As Joe said UTM zones do not overlap by definition, but that does not mean that you cannot project features existing in one zone using an adjacent one. The issue is not immediate locational error, but progressive shift, map distortion and therefore area and length. Depending on how far north you are you can probably use an adjacent UTM zone as the projection say half way across a few hundred km ... or anywhere say 3 degrees of longitude before things start to get noticeably out of shape and if projected out of alignment by say a meter at mid latitudes.
That is why there are other projections like Albers to preserve area across several zones. But project to excess across a few zones and you will see shifts and severe area distortion like these shots of Lake Superior in a screen projection of UTM Zone 15N (with a background map in NAD84 Web Mercator Auxialiary Sphere). The progessive offset was the result of projecting a shapefile from zone 15N into 14, 13, 12, 11, 10 and 9 shown overlapping to the west with the zone 9 on top. In 14 there is only about a meter of offset but the area is also significantly changed in the shapefile. Progressive westward errors in meters from the zone 15N projection; UTM14N = 1m, UTM13N = 25m, UTM 12N = 314m, UTM 11N = 2500m, UTM10N = 18000m, UTM9N= 102,000m. Areas are displayed as square meters in a jumble with the minimum being the zone 15N projection and the max 9N. The larger red number is the area in a continental Albers projection.
So based on that you have to decide what precision you can tolerate whether you are using a UTM projection or Albers.