[postgis-users] St_length anomaly

[Bob Pawley]

Hi

I am running geometry at srid –1.

I have an interesting anomaly when identifying or rejecting a st_length2d linestring.

I have a linestring with it’s own row and id, and a length of 1.50812109467324e-008 (according to postgis).

However when I attempt to exempt all linestrings shorter that 0.02 this very short linestring is included as being longer than .02.

I checked the geometry on QGIS and it shows as being much shorter than its immediate neighbours(lengths of 0.0625000012910668)  that are rejected as being shorter that 0.02.(perhaps a nervous drafter or an anomaly in the transition from dxf)

Actually, it still gets included even when I use st_length greater than 1.6. But it is finally rejected when using 1.7 as a minimum length.

It’s almost like postgis is calculating the numerals and ignoring the e-008.

Is there another explanation for this(I hope)??

Bob
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