Converting PostGIS point to text causing loss of data?
You are likely correct in your thought that the conversion using ST_AsText is causing a loss of precision. This is actually stated as a warning in the documentation found here: ST_AsText
WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for transport.
Basically you want to do any operations while the geometry is in a binary form to ensure you get full precision.
Now, in the larger context of your question, this would seem to indicate that there is some gap between the start of one segment and the end of another. If they are supposed to be coincident, then you have two options:
- Edit the layer and snap the endpoints together. Continue on.
- If this data is supplied from an authoritative source, you may want to let them know about it so the data may be fixed there then propagated out again. This may take longer, but would contribute to better data quality in the long-run.