In stereographic projection you can plot geological features as planes  and lines. You can considered the slope as a line. this line has the direction of slope (the trend of slope measured from the north direction) and an angle of plunge (the angle of slope measured downward from the horizontal). You can plot the slope using these two values  ; trend and plunge. The methodology of plotting is explained in details in many webpages (e.g. https://www.uwgb.edu/dutchs/structge/sl71.htm). The line will be represented in the projection as a point. 

The methodology of plotting is explained in details in many webpages (e.g. https://www.uwgb.edu/dutchs/structge/sl71.htm).

Dear Dr. M.A.Waheed,

I do not understand why we have to consider slope as a line? Generally structural geologist plot line structure which is present on a plane. Your answer looks absurd to be me because no logic behind this answer to satisfy me.

Hello,

I am not certain if I understand you question correctly, but perhaps it will help if I explain how I plot planar data, and how I usually interpret slope from an equal-area lower-hemispherical projection.

In my experience, there are three conventions for communicating the orientation of a plane (orientation includes both the dip/slope magnitude and the direction in which it is sloping/dipping): [1] as a 'great circle' arc that connects from one side of the circular plot to the other; [2] as a point that marks the projected position of a line that matches the down-dip (down-slope) direction (i.e., the steepest possible direction ON the plane); [3] as a point that marks the position of the plane-normal line direction.

I have tried to attach an example equal-area lower-hemisphere plot I made just now. In this plot, the thin arc line is a great circle arc that traces where the edge of the plane would intersect the bottom of the projected hemisphere. The triangle marks the 'down-dip' direction on the plane (not that it intersects the arc, because it represents a line that exists ON the plane). The square represents the plane-normal line (a.k.a. the pole to the plane)... note it does NOT intersect the arc... which is good because it does NOT lie within the plane (it is normal to it). 

In all cases, the magnitude of the slope/dip is communicated by the distance in the projected plot space from the edge of the circle (and/or the distance from the center of the plot). In the example I attached, the plane slopes 45º, so the distance from the center of the plot for both the triangle and the square are identical. Note: a vertical line/direction would plot as a point in the very center of the 'stereonet'.

Does that help at all... or make sense?

cheers.

Dear Professor Zachary Michels,

If you mean the dip of a plane, it is plotted exactly the same way as in the Lambert-equal area net.  Structural geology lab manual which has step-by-step instruction how to plot 1) a plane with its strike and dip and 2) a line with its trend and plunge. I know that which you explained me my dear.

But I mean slope. So far I know Dip and slope is not same. In standard literature terminology used as 1) Dip angle 2) Slope angle. I have learned that Dip is used for measurement of inclination of rock strata/plane.

Please give me some reference of book where Slope is also plotted as Dip of a plane or line with its trend and plunge.

Is it now clear to you,I mean my question?

best of luck,

Hi. Sorry, no that doesn't help. It seems you have not yet explained how it is that you understand slope to be different from dip. To me they are the same, but I am not the one with the problem. It was also unclear from your original post (and responses to others' attempts to help you) that you had any clue how to plot any data on a hemispherical projection, so that is why I thought to start there. Perhaps if you find the words to communicate what you think slope means – and precisely how you interpret that to be different from dip – then someone (else) mught find it worth their time to continue trying to help you. Best of luck.

A slope angle can also be described as the dip angle of the slope. Without further clarity regarding how you perceive the geometry of a slope to be unique from any other plane... It mostly sounds like you are confused by terminology. However, it is not complicated, and I think with some basic internet searching you can find the resources and references you need. The previous posts by others might be a good place to start.

cheers.

Thank you for helping me in a wrong way and to instruct to direct me to search net.

best of luck 

you are very welcome.

enjoy your search.

cheers.

 Hello Mr. Syed,

I am not sure if my answer would be satisfying or not, but what I understand is :

1. Slope is a term related to 'topography' and dip is a structural term related to inclined beds. Nonetheless , both of them are angles measured from horizontal.

2. Since the slope is an angle, yes, it can be plotted in a stereonet in a form of plane (strike/dip format) or in form of line (trend/plunge). In both the cases the orientation of the sloping surface must be known along with its slope angle. 

3. For example, consider you have to plot the sloping faces of a linear ridge with horizontal ridge axis.The strike direction for both the faces of the ridge will be same (i.e the strike of the ridge axis) , the dips will be opposite. The final plot will be the same as an antiformal fold plotted in the stereonet.

Consider another case when you have to plot the sloping surfaces of a valley. It would be the opposite case of the previous one. The final result will look like the plot of a synformal fold plotted in the stereonet. 

All you need to have to plot any kind of plane/line in stereonet is a pair of data: 1.Orientation w.r.t North and 2. The dip/plunge angle. 

In case of slopes of a topographic feature I believe you'll have to determine the slopes and corresponding strikes from a toposheet.

Best of luck!