Vertical control framework with levelling method as the based for detailed mapping in UNS Campus of Pabelan

Detail maps are one of the outputs created by measuring soil and mapping the topography of the earth’s surface on a huge scale. Preliminary steps must be completed, including the creation of fundamental mapping framework points that are evenly scattered across the area to be mapped. The goal of this study is to construct a vertical control framework and determine the accuracy of vertical control frameworks basic outline points in the form of polygons, measuring, processing data, displaying in the form of different height images and verifying their accuracy, and assessing the findings comprise the implementation technique. Vertical Control Framework measurement employs the chain levelling method and a levelling measuring tool. The results of the data analysis obtained a high difference of 8 mm in the results of the point before the correction, so the calculation of the height of the point after correction so that the height of the point equals zero in order to meet the feasibility as the basic framework of detail mapping and can be used for further measurements. The implications of the vertical control framework are utilized as a guide to generate a detail map.


Introduction
Soil measuring, often known as surveying, can be used to estimate the relative position of a point below or above the earth's surface.Soil measuring, in general, can be defined as a science that encompasses all methods for gathering and processing measurement data information about objects on Earth, whether natural and man-made, such that it can be clearly located or positioned [1] [2].
A map is one of the outcomes or outputs of soil measurement activity (mapping).In general, a map can be defined as an image or depiction of the earth's surface that depicts information using symbols.A comprehensive map is one of the outputs of the process of soil measurement and topographical mapping of the Earth's surface on a large scale.A detailed map measurement is a measurement used to generate a map that can represent both the horizontal position (coordinates x, y) and the position of height or elevation in the field (z) [1].
There are various preliminary steps that must be completed before making a thorough map, including washing the basic frame points of mapping reasonably uniformly on the region to be mapped.The basic mapping (control) framework is separated into two parts: the horizontal control framework (planimetric) and the vertical control framework (height) as a determinant of the coordinate point of the building to be formed into a detailed map and details [3] [4].The UNS Pabelan campus is the UNS's fifth branch campus, located right next to the UNS Hospital.The Uns Pabelan campus does not yet have a precise map of the situation and specifics, also, some new buildings have been constructed on Campus V UNS Pabelan.
The goal of this research is to create the design of vertical control frameworks on the UNS Pabelan campus, as well as to determine how the accuracy of the vertical control framework on the UNS Pabelan campus, which will later be used as a basic framework for detailed mapping on the UNS Pabelan campus.
The measurement work will generate size and map data that can be used to inform plots of land ownership, land use, land surface height expressed by contour lines, maps or plan drawings for project preparation, drawing land boundary lines, measuring land area and volume, and selecting a suitable location for a project [5][6] [7].
The benchmark or peg installation is a job that is done to help and save time on soil measurement (surveying) activity, particularly in the establishment of basic mapping frameworks.
Control points can be divided into two types based on their nature and utility: fixed polygon points made of concrete monuments and installed in small areas such as cities or industrial and residential areas, and temporary points that are temporary points, both manufacturing and use in measurements such as wooden pegs, yalons, and measuring signs.
Direct measuring is a fundamental skeletal mapping approach that is performed at each designated point along the path.For example, before making measurements, the points P1, P2, P3, P4, and P5 are determined as depicted in Figure 1 [4].Then, in this direct measurement process, the aircraft is established at each point by aiming at the point after, for example: the measuring aircraft is established in P1 by aiming towards P2, the measuring aircraft is established in P2 by aiming towards P3, and so on.This direct measurement is typically employed on territory with irregular elevation (steep).Indirect measurement is a basic skeletal mapping technique that involves leaping over one point from the previous measurement site as depicted in Figure .2 [5].For example, before taking measurements, determined points P1, P2, P3, P4, and P5, then in indirect measurements the measuring aircraft is not established at each point but is established at odd point only or even point only, for example: the aircraft is established at point P1 then the measuring aircraft will aim at points P5 and P2, point P3 aircraft will aim at points P2 and P4, and so on.This indirect measurement is commonly employed on flat land.The process of estimating the height of a number of places or measuring the difference in elevation is known as levelling.The difference in question is the height above sea level to a specific point along a vertical line [6].The axis line on the plane, which is depicted on the vertical sign, will define the difference in height between the locations.Levelling is also the notion of assessing the height difference between two or more points using a horizontal crosshair directed at upright signs (vertical) [6].If (a-b) the result (+), then from point A to point B rises, or in other words point B is higher than point A. Whereas if the result (-), then from point A to point B down, or in other words point B is lower than point A. [1] If the distance between the control point is relatively far, the measurement of the height difference with the flat insertor cannot be done with a single tool stand, then between two consecutive control points made several slag with auxiliary points and the measurements are made in a chain.[1].

Methods
This study uses experimental research methods conducted gradually in the period January 2021 -June 2021.The process of data collection is carried out by observation which includes research instrument preparation activities, control point assessment, surveying, data analysis, and depiction of vertical control frameworks according to the data that has been obtained.Data obtained from the results of direct measurements in the form of readings of waterpass aircraft thread, aircraft height, peg height, and distance.Data analysis techniques are performed using levelling measurement methods.This research procedure consists of the stages of preparation of research instruments, cooking, direct measurement in the field, data analysis, product design drawing, expert validation, and product revision.

Results and Discussions
This research examines how the vertical control framework is designed and how accurate the vertical control framework on the UNS Pabelan campus will be used as a basic framework for detailed mapping (Topography) on the UNS Pabelan Campus.In this research, the process of data collection is carried out by observation by preparing research instruments, cooking, and measuring (surveying) directly on the research object, namely the UNS Pabelan campus.

Preparation of Research Instruments
Preparations carried out include borrowing tools, preparing materials, making peg, and checking the function of measuring instruments such as, waterpass condition checks, measuring signs, and statif.

Field Orientation
Orientation in the field is carried out before making measurements.Field orientation aims to know the state of the field to be mapped so that later it will facilitate in determining the position of control points that will be used in the measurement process [1].Installation of peg and also sketch depiction of distribution of control points is also carried out at the time of field orientation.In determining the control point there are several criteria that must be considered, namely.
-Between the three adjacent points are visible to each other.
-The distance between points ranges from 10 meters to 20 meters.
-The position of the point does not interfere with the surrounding environment.
It can cover all the locations to be mapped.In this measurement will be obtained data that will be used as a basis in determining the difference in the height of the region to be mapped.The data needed in this measurement to be able to determine the difference in the height of a region is the reading of yarn on ppd / waterpass aircraft (upper thread, middle thread, lower thread), plane height, peg height, and optical distance.The height difference measurement steps for vertical control frameworks use the chain levelling (slag) method as follows: a) Install a Waterpass measuring instrument on a statif that is established between two that will be measured different in height as depicted in Figure 6. ) Orient waterpass by plumb or with optical centering so that it is just above the predetermined point.Set the nivo bubble to be in the middle (leveling) as depicted in Figure .7. c) The distance between the face and back of the levelling gauge is relatively the same.d) Aim for the measuring tub, then record the measurement results into the measurement form as depicted in Figure .8. e) Move on the next slag.Repeat steps a to d so as to get the required data.
Perform points a through e steps to measure other vertical control framework points.

Data Analysis
In the process of data analysis both direct and indirect measurements using the same formula except in the determination of height differences, in the determination of height differences there are differences because direct measurements only aim in the front while indirect measurements aim in the front and back directions.
Here are the stages of analysis of levelling measurement data.

Results
In this study, 44 control points were generated tied to the Bench Mark (BM) point which is at the south intersection of building A on the UNS Pabelan campus.The tool used in this study is Waterpass with the following accuracy.Fhmax = 10 x √Σd Fhmax = 10 x √796000 Fhmax = 8.92 mm So in this study the maximum height difference correction is 8.96 mm which means that the error in the measurement of the height difference (Fh) must be ≤ 8.96 mm.If Fh > Fhmax then it must be remeasured.
From the analysis of the data carried out, it can be known that the high difference correction obtained whether it meets the requirements of corrections different from the levelling method.From the results of data analysis obtained the results of high difference correction as follows.
Fh = starting point heightend point height Fh = 751 -222 Fh = 529 mm Because Fh > Fhmax, high difference correction is declared not to meet the calculation requirements with the levelling method.That way, it must be re-measured.
Before re-measuring, researchers must make observations first to find out points that have a very significant potential for high-difference correction in order to minimize errors.
After the re-measurement, the final result data is obtained from a difference in height of 743 mm, the result of correction of the difference in height after the re-measurement is as follows.
Fh = starting point heightend point height Fh = 751 -743 Fh = 8 mm So the high difference correction resulting from the re-measurement is 8 mm.So with a correction of the maximum height difference is as hard as 8.96 mm so that it can be declared Fh < Fhmax Has met the calculation requirements with the levelling method so that the calculation can be continued to calculate the high difference correction at each point so that the data is obtained high point after correction.After getting a high point result at each control point in this study, the researcher continued the next stage of drawing high on each control point in accordance with existing data using the autocad application.

Figure 3 .
Figure 3. Determination of height difference with levelling Description: A and B : the point above the earth's surface to be measured the difference in height a and b : the height of the crosshairs at points A and B HA and HB : the height of points A and B above the reference field ΔhAB : the height difference between points A and B The height difference between A and B is formulated as: ΔhAB = abIf (a-b) the result (+), then from point A to point B rises, or in other words point B is higher than point A. Whereas if the result (-), then from point A to point B down, or in other words point B is lower than point A.[1] If the distance between the control point is relatively far, the measurement of the height difference with the flat insertor cannot be done with a single tool stand, then between two consecutive control points made several slag with auxiliary points and the measurements are made in a chain.[1].

Figure 4 .
Figure 4. Determination of The Difference in The Height of The Chain Levelling Description: A and B : fixed points to be determined the difference in height 1 and 2 : points to help measure bA, b 1, and b2 : readings of signs behind mA, m1, and m2 : face sign readings To calculate the difference in height between two points with slag can be calculated using the following equation: ΔHAB = Σ Δh = Σ b -Σ m Description : Δh : different height of each slag Σ b : number of readings of the back sign

Figure 5 .
Figure 5. Research Chart 3. Levelling Measurement (Surveying)In this measurement will be obtained data that will be used as a basis in determining the difference in the height of the region to be mapped.The data needed in this measurement to be able to determine the difference in the height of a region is the reading of yarn on ppd / waterpass aircraft (upper thread, middle thread, lower thread), plane height, peg height, and optical distance.The height difference measurement steps for vertical control frameworks use the chain levelling (slag) method as follows: a) Install a Waterpass measuring instrument on a statif that is established between two that will be measured different in height as depicted in Figure6.

1 . 4 .
Write the values ba (top thread), bt (middle thread), bb (bottom thread), rear distance, and face distance.2. Search for crosshairs error values.3. Calculate BT corrections on each slag using the equation : bt = + 2 Calculates the optical distance (d) of each slag using the equation : d = (babb) x 100mm 5. Calculates the total optical distance (Σd) by summing all the slag distances.6. Calculate the accuracy of the maximum height difference measurement (fhmax) as a reference for high difference errors with the formula : Fhmax = 10 x √Σd 7. Calculate the difference in height (Δh): Direct measurement using formula: Δhm = tpbt Indirect measurement using formula: Δhb = bttp (back) Δhm = tpbt (front) 8. Calculates the high difference correction (fh) using the equation : Fh = end point heightthe height of the starting point.9. Calculates the magnitude of the correction of each point (khi) using the equation : khi =   x fh Description : khi : major correction of each point d : optical distance of each slag Σd : total optical distance Fh : correction of different height 10.Calculate the height of the measurement point (Ti) by summing the height of the previous point with the height of the correction point whose result is equal to zero.11.If it is not equal to zero then the calculation of the height of the point after the correction with the following equation : Ti = the height of the starting point ± Δh + khi Description : Ti : height of measurement point Δh : different height khi: correction of each point

Table 1 .
Measurement Results