Landscaping and Gardening Info

More of the basics of landscaping before getting to the actual doing of the landscaping. In this landscaping lesson it describes how to measure off and create a “map” of where your landscaping will be done by means of pacing. We use the first method, sort of, ourselves when figuring out how to and where to add certain aspects to our own landscaping. It is effective enough if you have a large area within which to do your landscaping.

LESSON SEVEN

Below are two methods of making paced surveys. Such surveys are frequently used in landscape gardening. It is important that everyone who does any sort of work in landscape gardening, even the pupil in school or college, should be familiar with the practical methods employed and should have some experience in making surveys.

Definition

A paced survey is one in which all, or most of the distances are measured by the worker pacing, or walking, from point to point. Sometimes when large areas are to be mapped as in military work, distances are measured by counting the steps taken by a horse, or by observing the time taken by a horse to traverse them.

Discussion

The paced survey has several practical advantages. It can be made quickly by one man working alone without expensive instru­ments. It is therefore rapid and inexpensive. Without previous practice the average man will work to about 10% of accuracy, making the distances too short on account of over-stepping. With practice it is possible to reduce the error to two or three per cent.

Although not absolutely accurate as to distances the relation­ships of parts are correct, and such surveys are accurate enough for plans to accompany general directions and explanations to assist­ants and clients, for rearrangement plans where little grading is proposed, for approximate location of details for the guidance of experienced foremen, for making planting plans and for records of information in study of existing designs. They are not accurate enough for figuring amounts in grading.

Equipment

The worker should be equipped with a compass (see Lesson 8). He should also have one or several sheets of cross-section paper mounted on a drawing board. It is possible, of course, to make paced surveys while recording the notes on any stray sheet of paper, but the cross-section paper will help greatly. A pair of tri­angles and an engineer’s scale should be used.

General Directions

Pace Length: Do not try to take an unnaturally long step, it is tiresome and cannot be continued with an uniformity. The ordinary step is not far from two and one-half feet, often a little more, and one is apt to lengthen it in pacing so that care should be taken not to overstep. For areas of a few acres the best plan is to take the natural step considering it two and one-half feet and keeping count in feet rather than number of steps. Starting with, say, the right foot, counting five, ten, fifteen feet, etc., each time it is placed; distances may then be plotted in feet with the engineer’s scale.

When considerable areas are to be surveyed so that long dis­tances are paced and the accumulated error would amount to con­siderable, more correct results will be obtained by finding the true length of the pace by counting the number taken in a measured distance of considerable length. This is the method used in military surveying. A table of corrections for various slopes may be worked out and applied in order to give correct horizontal distances.

Two methods are in common use:

1. In which objects are located from base lines by two paced distances usually at right angles to each other.

2. In which objects are located from some central point, the direction being read by a compass and the distance paced.

The first method is more useful for areas of a few acres, especially if about a building.

Method I
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In this method the plan should be plotted on a piece of paper ruled to squares; engineers cross-section paper is best. It is ruled ten spaces to the inch and each space may be taken as a foot, or as two feet, making the scale of the plan 10′ or 20′ to the inch, or more if desired. The sides of the main building give good straight lines, and their extensions may easily be located as they cross the grounds. Usually a building will give two such lines in each direction and sometimes more. When there is no building, a straight fence may be used as a base line, or three poles may be set up in line. Three will define the line at any point while if two are used positions on the line cannot be determined between them. A straight line on the ground, as a railroad-edge or ditch will do, but this is not so good as something which stands up so as to be easily seen.

One of the heavy lines on the cross-section paper should be assumed as representing the base line on the ground, or two at right angles should be taken to represent the best defined sides of a build­ing. It will not be possible to locate the details of the building ex­actly by pacing and if special accuracy is desired for these measure­ments it will be better to tape them. This may be done by fastening the zero of the tape at one corner of the building and recording the readings at each side of windows, doors, etc., to the next corner, and
similarly along the other sides. With this information the building may be easily plotted.

Pacing is not sufficiently accurate to give good results by triangular ties, even small errors in measurement will throw the intersec­tion of the arcs too far from the correct position. The pacing should be on 90° ties, that is along lines at right angles to the base lines. A point should be found in the base line where a line at 90° to it will pass through the object to be located. When the distance to the object is short such a point may be found by estimation, for greater distances stand on the base line, stretch the arms along it, and (without looking at the object) swing the arms together, if they do not point toward the object move along the base line and try again till the proper place is found. When a drawing board is used to hold the paper, right angles may be found by sighting along its edges or a right angle mirror or prism may be used.

Pacing should be done from the point on line to the object, as the point must be found first and the object is more easily seen from a distance.

Do not locate an object by pacing from one base line along another to the right angle point, as this would include any error made in the location of the right angle point. Such an error of lo­cation would have little effect on a distance at right angles to the base line.
Sometimes objects intervene so that it is not possible to pace along a desired line; it is then often possible with a little care to offset and pace along a parallel line.

Gain general control of the problem first, - that is, locate boundaries, fences, important roads and the larger objects as other buildings, etc., and then fill in the single trees, walks, shrub beds and other details.

Locate everything possible from the original base lines. When objects are to be located from other objects be sure that the first locations are correct.

When locating a line at an angle to the base line tie in its ends, or if more convenient some point in the prolongation of the line. A row of trees may be plotted by locating the end ones and pacing along the line to locate intervening ones.

Locate curves by right angle ties from the base lines to as many points as desired. Avoid unnecessary walking. Often in pacing a distance intermediate objects, as road edges, etc. will be passed; if so, make notes of the distances to such objects and later plot them.
Check your work occasionally by general inspection of the plan
and correct any mistakes.

In plotting it will be less confusing to orient the plan so that
objects will be in their proper relations. Omit foliage lines till all location is done and then sketch them by inspection in relation to various objects.

An approximate north point should be shown. It may be determined approximately by holding a watch flat in the hand with its hour hand directed toward the sun (that is with its shadow under it); then half way between the hour hand and twelve will be the north and south line.

Method II ;

In the second method, where a compass is used, select some
central important object such as a tree or building corner, and stand­ing at it, take the bearings of a considerable number of other ob­jects. Then pace from the central station out to an object and crossing over to some other object pace back to the central station so as to save walking. Intermediate objects along a paced line should be noted. The notes of such a survey may be recorded either in tabular form in a notebook with columns showing the station, direction, distance and object, or in a diagrammatic form with the objects roughly sketched in relation and the direction and distance shown along lines from the central station. Additional stations may be located from the first one and the work carried along as required. Such a survey must be plotted up by means of a protractor. It is much better to use a compass and a protractor graduated in azimuth to 3600 rather than to quadrants. This method requires less time in the field and more in the office than does the previous one. It also requires the use of compass and protractor. The results are perhaps not quite so accurate, as it is not possible to read courses very accurately with a hand compass.

Practice

The student must have actual practice in making paced sur­veys. Indeed he must have extended and frequent practice. Speed and accuracy are gained by such practice, the improvement in accuracy being especially important.

Therefore let the student undertake surveys of this kind as often as possible. It will be better naturally to begin with simple problems where only a few details are to be located and proceed to the study of larger areas and rougher land with more intricate de­tails. It will be better also to select areas which have some in­trinsic interest or those for which the finished maps may be of some further use, either in the present course of landscape gardening studies or for other business.

Rather a long landscaping lesson today, but we figure to more quickly get these basic lessons out of the way to see what more our landscaping book has to teach us about landscaping. You may wish to try the first method of doing a pacing survey within your own landscaping.