MerseyViking

Liverpool, United Kingdom

geospark.co.uk

Age: 42

Maps. Archaeological geophysics. Programming. The holy trinity of my science geekery.

I'm a freelance geospatial and archaeological software developer.

Apr
3
awarded Yearling
Apr
3
awarded Yearling
Mar
21
comment Earth resistivity meter design
Interesting! Thanks for that Marko - my budget could stretch to a fairly cheap one to play around with and compare results with one designed for archaeology.
Mar
21
awarded Scholar
Mar
21
accepted Earth resistivity meter design
Mar
21
comment Earth resistivity meter design
That's fantastic, thanks JIm. Just the sort of thing I was after. The rest of the device - microcontroller, displays, input, logging and all that are fairly straightforward for me as a programmer (my main job) and tinkerer (I made an internet-controlled kettle for a client once - don't ask, but I got paid). It was really just the high voltage stuff that I didn't want to mess around with until I had something to work from. The GPS part generally isn't used - we divide the site into 30m squares that we survey in with theodolites and paper maps (archaeologists are slow movers with technology).
Mar
21
comment Earth resistivity meter design
I'm no expert on those sorts of devices, but I suspect they would be inappropriate otherwise archaeologists would be using those! Check the Wikipedia article I linked to for a general description of operation.
Mar
21
comment Earth resistivity meter design
Don't think of a archaeological res meter as a piece of lab equipment, but as something people throw in the back of a 4 wheel drive and generally abuse. Indeed, absolute measurements aren't important (as long as they are consistent), we are looking for variations in soil moisture at typically a 1m grid spacing over a usually large area in as short a time as possible. Also, archaeologists have no money - local archaeology societies are mostly volunteer-based, and finding $5000+ for a machine is very hard, and they don't tend to get resold because of it.
Mar
21
awarded Student
Mar
21
comment Earth resistivity meter design
Surely Marko, if I were an EE freak (I consider myself a hobbyist), I wouldn't be asking questions - or has SE become so exclusive that I need to be an experienced professional before asking a question? It's a good job I am thick-skinned otherwise I might be scared off by your elitism. My assumption is if a working device can be published in a hobbyist magazine, it's not beyond a hobbyist's ken to improve upon it. I understand I may not be asking the right question - in which case some gentle guidance would be appreciated.
Mar
21
comment Earth resistivity meter design
The RM15-D spec sheet gives a maximum contact resistance range of 10kΩ to 1MΩ at 100v
Mar
21
asked Earth resistivity meter design
Mar
14
awarded Supporter
Mar
14
awarded Autobiographer
Feb
12
awarded Autobiographer
Feb
12
awarded Supporter
Jan
18
comment longitudes look flipped when displaying geoserver kml on google maps
This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post - you can always comment on your own posts, and once you have sufficient reputation you will be able to comment on any post. - From Review
Jan
18
comment Convert .tiff data to bitmap just when rendering and at runtime by visualC++ code
This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post - you can always comment on your own posts, and once you have sufficient reputation you will be able to comment on any post. - From Review
Jan
18
reviewed Leave Open How to install pl/r pl/python pl/v8 in Ubuntu?
Jan
18
reviewed No Action Needed Polygon to Raster tool while keeping less than maximum values
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