[Qgis-user] Drill hole section with QGIS 3

[Ramon Andinach]

Hi Calvin,

In geology, we use a set of drill holes into the ground to interpret the space in the earth between them. Depending on what the geologist is interested in, we might be plotting the location of an aquifer, or a gold seam, an oil reservoir or some other feature. Note here, that I’m deliberately picking things that have length, breath and depth, so just interpolating a surface is not the same thing.

So, things that you might want to be able to do include:
 display attributes of the drill hole on a string representing the drill hole (or drill trace) in real 3D space.
 Create slices (sections) of these drill traces (so depth is the right and left side), with windows of included data on either side of the slice.
 Draw polygons snapped to the drill trace to link areas with similar features between holes.
 Build a mesh/wireframe model that links the polygons together
 Get a volume of said model
 Create a voxel model of an attribute/s distribution within the mesh.

This is probably a slightly economic geology skewed view, but hopefully I’ve left enough geo-jargon out that it’s understandable[1]

Depends on how complex you want to be. A well known GIS package in my neck of the woods trumpets the ability to do the slice and dice and section bit, but really it’s making up non-earth plans and dressing them up as having proper depth (a section). For some people that seems enough. 
But - that sort of approach makes it really difficult if what you’d really like to do is show just the bits of the drill holes with say, gold grades greater that 20g/t - leaving any other result as transparent - and spin it slowly around in 3D so that you can get a sense of the go/d’s distribution pattern. This last one is much more complex and only possible if you’re working in a truly 3D environment. 

Hope that makes some sort of sense. Feel free to ask for clarification.

Ramon.
[1] I’ve made an attempt to swap out terms I’m used to using for more generic explanations or more comp sci friendly terms. Hopefully, mostly understandable to both sides now.


> On 15 Mar 2018, at 20:31, C Hamilton <adenaculture at gmail.com> wrote:
> 
> Pardon my ignorance on the matter, but what does a drill hole capability mean? Is it simply making a hole in a polygon or is it much more complex.
> 
> Thanks,
> 
> Calvin
> 
> On Wed, Mar 14, 2018 at 3:46 PM, John Harrop <jcharrop at gmail.com <mailto:jcharrop at gmail.com>> wrote:
> It looks like no one has been answering this for you yet and I’m just catching up on a few days emails after my computer was in the shop.
> 
> There is active interest in developing a drill hole plugin for QGIS3 now that 3D is more fully supported.  I also work with drill holes and have been running them in QGIS fairly easily in plan view where I just calculate traces to a plan view (either in a spreadsheet or using code) and apply theme patterns based on the attributes I kept with the segments.  This has worked reasonable well with grade and lithology which are two of the main things you want to see.
> 
> Cross sections have been harder, but those are still “maps” in non-Earth coordinates.  Again I’ve tended to build those with projections to a plane in either a spreadsheet or by code.  This is not as easy to work with as plan view so I am very interested in seeing the developing interest in getting a drill hole section plugin for QGIS.  That will really finalize QGIS as the logical choice for geological exploration work.
> 
> I’ve cc’ed the others I know using QGIS so I hope you can be included in the list of interested users.
> 
> Regards,
> 
> John Harrop, PGeo, FGS
> Senior Project Geologist
> Coast Mountain Geological Ltd
> 
> PO Box 62
> Suite 488 - 625 Howe St
> Vancouver, BC   V6C 2T6
> 
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