Doug Thanks for the reply. I am not sure what is different with the three zone gridding and just gridding with the small size for all data? In both cases you are creating the grid in the low data density zone with high density cell sizes? Does you attached image (grid) looked much different than you initial attempt (say at 25 m grid cell size)? I am sure that if you merge the 3 zoned grids into one grid that you would have some issues (a 1VD of the grid will show all of the edge effects). But if you use grid knit and have overlapping areas that should be eliminated as you alluded to in your email. If you go to voxi to model it, it won’t matter so much if you use the stations for data and not the grid since it will be the cell size that controls the data (if you chose 1 data point per cell size). Looks like a nice data set, should be fun to interpret. Glad to see you are still having fun in geophysics. Good hunting and discovery. Regards Dick
From: Doug Perkin <[email protected]> [mailto:[email protected]] Sent: Thursday, May 05, 2016 10:01 AM To: Geosoft Oasis montaj and Target Subject: Re: [geonet] Gridding Gravity data Hi Dick Thanks for your response, I did grid this with three zones and use the same color scheme as you suggested and it looks really good accept when you are interested in things near the boundaries of the zones. Riann Mouton suggested I try taking this a step further and re-grid/interpolate the coarser grid to the cell size of the smaller grid and window out the zone covered by the finer grid in the interpolated version of the coarser grid and then repeat the process till all 3 zones are in the smaller cell size. So the two coarser grids look like a donuts where the central part with the closer spacing is dummied. This worked very well since I had 25m, 50m and 100m cell sizes in the 3 zones. After regriding all 3 to 25m and windowing out the central parts of the two coarser grids you can try to connect the three grids using Grid=>Utilities=>Grid Mosaic from Grid files. I am still getting some edge effects at the boudaries of the grids so you probably need a row or two of cells at the boundaries so you can more smoothly interpolate between them. Doug On Mon, May 2, 2016 at 2:17 PM, Dick West <[email protected]<mailto:[email protected]>> <[email protected]<mailto:[email protected]>> wrote: Doug One method is to create three grids, central, 2nd and 3rd areas. You can grid the central area with the optimum grid cell spacing, go to the next zone and use the optimum cell spacing for that (and using that spacing for the high density core stations too) and then do the same for the out zone. You have three grids, three different grid cell size and you can drape them atop one another using the same color scheme. That way you maintain best resolution within a zone. But it always depends on the anomaly character and do the anomalies bleed from the higher density into lower density zones (in which case this does not work as well). Dick From: Doug Perkin <[email protected]<mailto:[email protected]>> [mailto:[email protected]<mailto:[email protected]>] Sent: Monday, May 02, 2016 1:53 PM To: Geosoft Oasis montaj and Target Subject: [geonet] Gridding Gravity data Hi I have a question about gridding gravity data in oasis montaj. What gridding settings are best for a survey with variable spacing like the image below? The spacing ranges from 200m to 800m depending on distance from AOI. I can get good results with default minimum curvature with 40m cell size in the high density part, but don't get very good interpolations where the spacing increases. Is there a way of doing a more regional grid with 200m cells then stitching it to the 40m grid? Any suggestions on the gridding settings here? Regards, Doug --- Forum archives can be accessed here: http://lyris.geosoft.com/read/?forum=geonet<http://lyris.geosoft.com/read/?fourm=geonet> You are currently subscribed to geonet as: [email protected]<mailto:[email protected]>. To subscribe or unsubscribe from any of our forums, select the User Forum selection on the Geosoft Community page: http://www.geosoft.com/support/community/forums/register/ --- Forum archives can be accessed here: http://lyris.geosoft.com/read/?forum=geonet<http://lyris.geosoft.com/read/?fourm=geonet> You are currently subscribed to geonet as: [email protected]<mailto:[email protected]>. To subscribe or unsubscribe from any of our forums, select the User Forum selection on the Geosoft Community page: http://www.geosoft.com/support/community/forums/register/ --- Forum archives can be accessed here: http://lyris.geosoft.com/read/?forum=geonet<http://lyris.geosoft.com/read/?fourm=geonet> You are currently subscribed to geonet as: [email protected]<mailto:[email protected]>. To subscribe or unsubscribe from any of our forums, select the User Forum selection on the Geosoft Community page: http://www.geosoft.com/support/community/forums/register/ --- Forum archives can be accessed here: http://lyris.geosoft.com/read/?forum=geonet You are currently subscribed to geonet as: [email protected]. To subscribe or unsubscribe from any of our forums, select the User Forum selection on the Geosoft Community page: http://www.geosoft.com/support/community/forums/register/
