OSGeo
GeoJSON: Decimal number inside extra member may get more decimals
If GeoJSON contains an extra feature member like this (sorry if it is not a member, I do not master the JSON vocubulary):
"kiinteistotunnuksenSijainti":{"type":"Point","coordinates":[461312.783,6685388.485]}}
then the numbers seem to go through a decimal->double conversion and the result from ogrinfo and from ogr2ogr conversions is
kiinteistotunnuksenSijainti (String(JSON)) = { "type": "Point", "coordinates": [ 461312.783, 6685388.4850000003 ] }
By comparison a numeric attribute "testnumber":6685388.485 is not changed and ogrinfo shows it unaltered
testnumber (Real) = 6685388.485.
How to reproduce:
ogrinfo base_3067.json -al
JSON numbers are stored as IEEE754 64-bit real numbers on JSON parsing (as most parsers do). Regarding the output back to decimal representation, this is just dependent on the number of significant figures selected. OGR is on the safe side, using potentially more significant figures than strictly necessary, to avoid any loss of accuracy.
$ python -c "print('%.17g' % 6685388.485)"
6685388.4850000003
$ python -c "print(6685388.485 == 6685388.4850000003)"
True
We have logic at a number of places to try to find the "minimal" decimal representation. Probably not used for that particular use case. Minor issue from my point of view
