How to Contour A Map

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    mhmoudkhlifa
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    How to Contour A Map

    مُساهمة من طرف mhmoudkhlifa في 2007-10-31, 3:38 pm





    Geologists make all kinds of contour maps. Contouring is not hard, but it takes lots of practice and patience to make a nice-looking map.
    You start by "spotting", or drawing, all the wells on a map. In a large part of the United States, the Township and Range System is used to spot wells.
    Let's assume we are making a map in one the western states that uses the Township and Range system. In this area, a "section" of land is one mile on each side (one mile square). This also happens to be exactly 640 acres.
    Here's a section of land to the right, with wells spotted on it.


    Next, you look at the electric logs for each well. We are going to make an "isopach" (eye-so-pak) map. An isopach map is a map that shows the thickness of something. In this case, it is the thickness of a sandstone formation.
    Count the number of feet of sand in the zone you are interested in. Then, put the number of feet of sand below each well spot.





    Start contouring with the highest values. Use a "contour interval" that is slightly less than the biggest values. In this case, the first line drawn is the 40-foot contour.
    As you draw your line, look carefully when you pass between two wells. Try to use your eye like a "ruler", and position the line at the proper distance between the two wells. Notice the well with a footage of "38". Since 38 is very close to 40 (the contour we are drawing, you should "pull" the 40-foot contour over close to the 38-foot line, like I did here.
    If there is a "40" on the map (there is on this one), you will draw the 40-foot line right through that well.


    Now draw the 30-foot contour. "Eyeball" the map and be sure to leave the proper amount of room for the remaining contour lines. Use a pencil, because you have to erase a lot!!




    Finish the map by drawing the 20-foot, 10-foot, and zero contour lines. Label the "contour interval" you used at the bottom of the map. In this case, the contour interval is 10 feet.
    You're done! It takes quite a bit of practice to draw decent contour maps by hand. The one we just did was a "quickie". Normally, you would draw this in pencil and then go back and make it better with ink.
    It's important to know how to contour a map, but these days, geologists use computers to do a lot of their contouring. The computer can't do it all, however. It still requires quite a bit of "help" from the petroleum geologist to make a decent-looking map.
    The map on the right would still require some erasing and reworking to get it looking right


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    رد: How to Contour A Map

    مُساهمة من طرف takey في 2007-10-31, 9:28 pm

    Very Good
    topic my friend,



    I want only to add that there is small difference
    between the human contouring and the computer contouring. In manual or human contouring
    normally, we use the linear function, but in computer contouring, we can choose
    the mathematical function of the contouring (variation in the phenomena) linear,
    exponential, logarithmic, etc….



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    salheen
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    رد: How to Contour A Map

    مُساهمة من طرف salheen في 2007-10-31, 11:00 pm

    nice topic khalifa although i prefer human contouring alot as it makes u understand well the nature of the area
    but i know how to do contour by computer in the same time as it is more fast


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    رد: How to Contour A Map

    مُساهمة من طرف عمرو ماهر الزيني في 2007-11-11, 10:28 pm

    ميه ميه
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    uno
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    رد: How to Contour A Map

    مُساهمة من طرف uno في 2007-11-25, 1:19 am

    yes the computer contouring is faster but with less accuracy as well
    i prefer manual contouring as sal7een and made checking up by the computer
    lol!


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    رد: How to Contour A Map

    مُساهمة من طرف exploder في 2007-11-29, 9:15 am

    شكرا على الموضوع الجميل ده
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    رد: How to Contour A Map

    مُساهمة من طرف abdovolcano في 2007-11-30, 12:34 am

    thanks
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    mohamed elzhar
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    رد: How to Contour A Map

    مُساهمة من طرف mohamed elzhar في 2007-12-12, 5:14 am

    كلامك صح يا صالحين وبعدين منا ممكن اعمل تصحيح للكنتورات على الكمبيوتر
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    mohamed elzhar
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    رد: How to Contour A Map

    مُساهمة من طرف mohamed elzhar في 2007-12-12, 5:18 am

    وبعدين انا ايضا مع عمل الكنتورات يدوى للمعرفه فقط ولكن خلاص بعد ماتفهم العمليه ماشيه ازاى لازم تشتغل على الكمبيوتر لان انت مش هتشتغل على 4 نقط ولا حتى 10 نقط ولكن هتشتغل على 100 او اكثر من ذلك ولا ايه رايكو؟؟

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