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Thread: how to create 2D or 3D Cross section

  1. #1
    Mina Rahimi
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    Default how to create 2D or 3D Cross section

    Hi,

    I need to create cross-section from borehole data in 2D or 3D. I've read that it is possible in Arcmap with 3D analyst.
    Does anyone know how I can create cross section?

    Thanks alot

  2. #2
    Mina Rahimi
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    Default Re: how to create 2D or 3D Cross section

    Hi

    Does anyone know extension to create or draw geologic cross section?

    Thanks in advance

  3. #3
    Hardolph Wasteneys
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    Default Re: how to create 2D or 3D Cross section

    Quote Originally Posted by mi_rah View Post
    Hi

    Does anyone know extension to create or draw geologic cross section?

    Thanks in advance
    Mina,

    This depends on the type of borehole data you have and how much automation you want etc.

    In 2D it is just making a vertical map and if you have enough survey data calculated along some grid for the boreholes and are happy with a projection into a plane in that grid you can do it with Linear Referencing in ArcMAP. Just create polylines from the coordinate data with your X being the horizontal coordinate (e.g. the Easting) and Y being the depth then create routes using the drill string length as the "M" value at each survey point. With that you can do a "make route event" to input your down hole data table for interval of the borehole using the 'from' 'to' values as the input.

    With that plotted you can do a conventional map job linking contacts, create some polygons and you have a cross section. I've used this method numerous times, but you have to be familiar with your data formatting. For a surface profile you would have it in the conventional way by plotting the contour line intersections, though i'm sure one could readily come up with something more elegant.


    If you want some sort of 3-d manipulatable model, I'd suggest getting "Target" for ArcGIS or the standalone version. It will have good input data verification tools for the tabulated lithologies and geochemistry as well as being able to create views from different orientations. It is probably the same price as 3-D Analyst, but a Geosoft product.

    If you already have 3-D analyst I can't advise you on any fancy way of making a cross section except that there will be cutting tools to at least make the topographic profile, but the problem is the input method for the downhole data. Perhaps the Linear Referencing method above can be done in 3-D with a Z value. That would seem to be a sensible thing for it to have , but I don't know and don't have 3-D Analyst to play with it if it did.


    good luck

    Hardolph
    Hardolph Wasteneys Ph.D., P.Geo.
    Geologist
    Vancouver Island

    hardolph@bravewolf.com

  4. #4
    Mina Rahimi
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    Default Re: how to create 2D or 3D Cross section

    Hi Hardolph,

    Thank you so much for helping me.

    My borehole data contains stratigraphic layers. At each X,Y I have the elevation of the bottom layer. For example, for X=1 And Y=1 , I have elevation for surface, elevation of bottom layer for next layer and etc at a given point. By subtracting the elevation I have the thickness of each layer.

    I never use Linear reference and I got confused with your answer, I would appreciate if you can explain the process more clear.

    Thanks again

  5. #5
    Mina Rahimi
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    Default Re: how to create 2D or 3D Cross section

    Hi,

    My data like this:

    Column/Row/X/Y/surface/layer1/layer2/layer3/.....

    In surface and layer columns are elevation. By subtracting layer1-surface, I have thickness of layer1.

    I have install ET-geowizard to create polyline, but it creates horizontal line.

    What should I do?

    Thanks

  6. #6
    Hardolph Wasteneys
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    Default Re: how to create 2D or 3D Cross section

    Quote Originally Posted by mi_rah View Post
    Hi,

    My data like this:

    Column/Row/X/Y/surface/layer1/layer2/layer3/.....

    In surface and layer columns are elevation. By subtracting layer1-surface, I have thickness of layer1.

    I have install ET-geowizard to create polyline, but it creates horizontal line.

    What should I do?

    Thanks
    Mina,

    that sort of data might typically be used for creating an isopach map (thickness of a formation in plan) or contour map of the elevation of a particular contact. From your description I assume that you have an array of vertical boreholes and that elevations have been calculated in place of depths in the holes. No need for Linear Referencing

    For cross sections you would first look at the map of the borehole locations and then decide where you want a section line and whether it will be a straight line with data projected orthogonally into it or if you want a schematic showing changes in thickness of a formation from one point (borehole) to another. You could use symbology to show something like thickness of a target unit to help decide where you want the section line.

    What form is the data table in? Shapefile or just excel or dbf table? ... Plot it up on a map by using the "add XY data" tool in which you could use the X and Y coordinates for the drill holes.

    For a simple 2-D cross section you need a section line and the orthogonal projection points of drill holes within some defined interval e.g. within 50 m on either side of the line. All you need next is the section line with some measure along the line of projection point of the drill holes. This could be a "buffer" that was used to spatially "select" the drill holes and export those to a new file.

    Make a new plot using the position measures as the X and the layer elevations from each hole as the Y. Even simpler if your section line is parallel to your grid lines then you can just make a new XY map with the line parallel coordinate as the X and one of the elevation Fields as the Y. Then repeat for each contact (layer1, layer2 etc) making a new set of points in each new layer for each contact.

    Now it is just a connect the dots exercise. Make a polyline FC or shaefile and snap lines for the contacts and vertical to represent the drillholes.

    If the exercise is more of GIS than a geology project you could use more elegant methods to do the plotting, but usually best to start off with the simplest method to see the problem and then look for more efficient ways fo handling a large data set, if that is the case.


    Hardolph
    Hardolph Wasteneys Ph.D., P.Geo.
    Geologist
    Vancouver Island

    hardolph@bravewolf.com

  7. #7
    Mina Rahimi
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    Default Re: how to create 2D or 3D Cross section

    Quote Originally Posted by Hardolph View Post
    Mina,

    that sort of data might typically be used for creating an isopach map (thickness of a formation in plan) or contour map of the elevation of a particular contact. From your description I assume that you have an array of vertical boreholes and that elevations have been calculated in place of depths in the holes. No need for Linear Referencing

    For cross sections you would first look at the map of the borehole locations and then decide where you want a section line and whether it will be a straight line with data projected orthogonally into it or if you want a schematic showing changes in thickness of a formation from one point (borehole) to another. You could use symbology to show something like thickness of a target unit to help decide where you want the section line.

    What form is the data table in? Shapefile or just excel or dbf table? ... Plot it up on a map by using the "add XY data" tool in which you could use the X and Y coordinates for the drill holes.

    For a simple 2-D cross section you need a section line and the orthogonal projection points of drill holes within some defined interval e.g. within 50 m on either side of the line. All you need next is the section line with some measure along the line of projection point of the drill holes. This could be a "buffer" that was used to spatially "select" the drill holes and export those to a new file.

    Make a new plot using the position measures as the X and the layer elevations from each hole as the Y. Even simpler if your section line is parallel to your grid lines then you can just make a new XY map with the line parallel coordinate as the X and one of the elevation Fields as the Y. Then repeat for each contact (layer1, layer2 etc) making a new set of points in each new layer for each contact.

    Now it is just a connect the dots exercise. Make a polyline FC or shaefile and snap lines for the contacts and vertical to represent the drillholes.

    If the exercise is more of GIS than a geology project you could use more elegant methods to do the plotting, but usually best to start off with the simplest method to see the problem and then look for more efficient ways fo handling a large data set, if that is the case.


    Hardolph
    Hi Hardolph,

    Thank you so much for your reply and your help.

    I found a way to create cross section in Arcscene (3D).

    First I have created a TIN from file for 15 layers then I have converted the line of cross section to 3D again for 15 layers based on each TIN, Finally I have added each of them to arcscene. I think it works.

    I did not understand well your way. My problem is to make a plot ;"Make a new plot using the position measures as the X and the layer elevations from each hole as the Y. "

    Here is what I have done: Add XY from tool then use X coordinate for X and Z for each hole as Y coordinate. However, they overlap each other and I cannot see the thickness of each layer from holes.
    Is it right or correct?

    Again thank you so much.

    Mina

  8. #8
    Hardolph Wasteneys
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    Default Re: how to create 2D or 3D Cross section

    Mina,

    If you have a good method in 3-D Analyst that cuts the TIN surfaces in a vertical plane and shows the intersections that's a good solution.

    With the 2-D method I suggested you can only plot a narrow horizontal range of holes (orthogonal to your section line) before the data overlap and become confusing. A solution would be to select a line of holes and then export them to a new FC. Then use that to connect the dots with polylines tracing the various layers. This is not as accurate as the TIN solution unless you interpolate between elevations for the same layer from holes on either side of the cutting line.

    Main thing is to be able to visualize the layers and it sounds like you have a good aid in ArcScene.

    Hardolph
    Hardolph Wasteneys Ph.D., P.Geo.
    Geologist
    Vancouver Island

    hardolph@bravewolf.com

  9. #9
    yamini rajan
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    Default Re: how to create 2D or 3D Cross section

    Hi,
    I have seen ur thread...I am new to GIS...i am doing same type of work..
    I am trying to create a 2D cross section using bore hole data in Arcmap...
    I have X,Y data, soil profile (i.e. fill, sand, etc..) and Z value depth as well as thickness for the corresponding soil profile.
    I have plotted X, Y points in Arcmap, then i tried to interpolate the points of each soil profile (i.e. sand, clay ) to get the cross section surface.. but it doesnt work.. i dont know how to move further to plot Z value....
    Based on which layer u have created TIN in 3D Analyst..
    Could u please explain me..
    Thanks..


    Quote Originally Posted by mi_rah View Post
    Hi Hardolph,

    Thank you so much for your reply and your help.

    I found a way to create cross section in Arcscene (3D).

    First I have created a TIN from file for 15 layers then I have converted the line of cross section to 3D again for 15 layers based on each TIN, Finally I have added each of them to arcscene. I think it works.

    I did not understand well your way. My problem is to make a plot ;"Make a new plot using the position measures as the X and the layer elevations from each hole as the Y. "

    Here is what I have done: Add XY from tool then use X coordinate for X and Z for each hole as Y coordinate. However, they overlap each other and I cannot see the thickness of each layer from holes.
    Is it right or correct?

    Again thank you so much.

    Mina

  10. #10
    Hardolph Wasteneys
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    Default Re: how to create 2D or 3D Cross section

    I don't know what your data file looks like, but the simplest way of understanding the problem is to do a map first as you've mentioned with the XY of all the boreholes; draw a line through a set of the boreholes and do a little pencil sketch reading off the vertical coordinates from the attribute table so that you understand what you're after from the data.

    Next make a new data frame with the same projection as before and use the "add XY" on your data file BUT specify just the X field for x coordinate and use one of the vertical input fields for Y. ArcMAP doesn't care what numbers you use.

    that will give you one set of points representing a layer of your cross section and you can just repeat for each elevation field you have and then draw some connecting lines.

    For a section line parallel to one of the coordinate axes it is a pretty simple method and no more complex than plotting by hand.

    to display the section you can do a layout and move the section line to where you want it. For an off axis section line, which would require a bit of geometry for the "x" coordinate you can rotate the data frame by the azimuth of the line and display it in the layout parallel to the section line.


    Hardolph
    Hardolph Wasteneys Ph.D., P.Geo.
    Geologist
    Vancouver Island

    hardolph@bravewolf.com

  11. #11
    Adam Read
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    Default Re: how to create 2D or 3D Cross section

    While ArcMap 10 supports vertical lines, the length of vertical lines is zero which is probably why linear referencing doesn't work for vertical wells. Of course, you can just subtract depth from the depth-datum elevation to get the elevation in this case, but with mixed data you'd have to use a separate method for vertical and deviated wells.

    On a related note, apparently, Arc 10 doesn't support 3d polygons with vertical sides (they collapse due to zero area). This makes it difficult to draw 3D sections using polygons unless you have a section that is just off-vertical.

    Another approach might be to draw a section in Illustrator or in "map view" (i.e. set Y = Z) in ArcMap, export as a raster, and hang it on the side of a multipatch rectangular object.

    All in all, the 3D functionality of Arc 10 out of the box is somewhat disappointing with regards to portraying subsurface geology...

    Quote Originally Posted by Hardolph View Post
    Mina,

    This depends on the type of borehole data you have and how much automation you want etc.

    In 2D it is just making a vertical map and if you have enough survey data calculated along some grid for the boreholes and are happy with a projection into a plane in that grid you can do it with Linear Referencing in ArcMAP. Just create polylines from the coordinate data with your X being the horizontal coordinate (e.g. the Easting) and Y being the depth then create routes using the drill string length as the "M" value at each survey point. With that you can do a "make route event" to input your down hole data table for interval of the borehole using the 'from' 'to' values as the input.

    With that plotted you can do a conventional map job linking contacts, create some polygons and you have a cross section. I've used this method numerous times, but you have to be familiar with your data formatting. For a surface profile you would have it in the conventional way by plotting the contour line intersections, though i'm sure one could readily come up with something more elegant.


    If you want some sort of 3-d manipulatable model, I'd suggest getting "Target" for ArcGIS or the standalone version. It will have good input data verification tools for the tabulated lithologies and geochemistry as well as being able to create views from different orientations. It is probably the same price as 3-D Analyst, but a Geosoft product.

    If you already have 3-D analyst I can't advise you on any fancy way of making a cross section except that there will be cutting tools to at least make the topographic profile, but the problem is the input method for the downhole data. Perhaps the Linear Referencing method above can be done in 3-D with a Z value. That would seem to be a sensible thing for it to have , but I don't know and don't have 3-D Analyst to play with it if it did.


    good luck

    Hardolph

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