JTS polygon intersection calc on a geoid

I am using JTS to compute intersections between polygons with WGS84 lat/lon coordinates. I am not converting coordinates to anything 2D based, just reading in POLYGON(lat lon, lat lon) and doing geometry1.relate(geometry2).

Will that give me correct answers all the time?

My polygons are roughly 1m to 100m in size, located in US and Alaska.

If it's completely wrong, should I convert WGS84 to UTM? Using JTS/GeoTools/Proj4J ?

• Welcome! Please take the tour: gis.stackexchange.com/tour and update your question to include what you have already tried and what you are having problems with. – MaryBeth Dec 28 '15 at 15:19
• Coordinates are usually in X,Y order, so your constructor should be "lon lat, lon lat,..." One meter is an awfully small area for a GCS geometry. – Vince Dec 28 '15 at 15:28
• @Vince you are correct. (lon,lat) sorry about that. 1m dimensions has to do with GPS coordinates (which are very accurate) and outlines of buildings. My JTS usage will be to see if person's gps location is inside a building, bounding box, or "hull" of the building. – Elijah Dec 28 '15 at 15:42
• I think you need to explain what you mean by "correct." – Rob Skelly Dec 28 '15 at 22:59
• By "correct" I mean that intersection of two geometries will be correctly identified by JTS library despite me using lon/lats. So far it seems that my test cases pass. But i cant tell if i'm lucky with test cases. – Elijah Dec 28 '15 at 23:11