Mobile Mapping

Im a geologist based in HK and currently use a Garmin 60 with Arcview

Im looking to upgrade to a better system such as GeoXH or mobilemapper in order to undertake mapping directly in the field.

I note both are supposed to be sub-metre accuracy but this seems to be related to there use in the US (eg H Star) and it is unclear whether post processing will be possible in Hong Kong

Grateful for feeback from any users

steve parry

Submetere precission is just a novelty in OSM, at this moment it would be a waste to use. There might be someone who knows something about it but it’s relevance to OSM is next to nil.

There are of course technical solutions to working with data that will be improved upon on a later date (postprocessed), you should be able to switch the incorrect coordinates which you worked with in the field with the one you get from postprocess. But I’m guessing there are no ready solutions for this other than using JOSM+perl and that’s not your choice of tools.

PS. I was expecting JRA to anser this as well I just wasn’t sure… :slight_smile: DS

I have been using Trimble GeoXT, Thales MobileMapper and Leica GS20 submeter units. They are accurate but accuracy does not come for free. They tend to drop the fix easily and it takes time to get it back. That’s probably because those units do not estimate the location by previous location, speed and direction like navigation oriented units. They suit much better for stop and go measurement than for collectiong traces in an OSM way. But for the real work in rather open fields they are OK. An alternative for post processing is to use differential correction either by having an own base station or utilising correction service. There may well be a free DGPS service available in Hong Kong because of the harbour and DGPS receivers are not very expensive. One more equipment in the same class is Topcon GMS-2. But as I said, they are not built for collecting traces in bad conditions.