A16.1 Survey: Summary - LUPMISManual

Annex 16: Entry and Display of Survey Data

Level of expertise required for this Chapter: Intermediate; general Map Maker training

Units can also be entered with their coordinates or data, as collected in the field by traditional, ‘old-fashioned’ survey techniques. The entry of polygons and lines through this method can be more precise, if conducted over short distances, but is more labor-intensive, more error prone and slower.

A menu-driven user-friendly entry system has been established at LUPMIS Drawing Tools (see Chapter 8.2).


A16.1 Survey: Summary

The approach: Entry of data in .XY file --> Convert to DRA file.

1. Have a listing or sketch of all points, which define the polygon(s) or line(s). These data can be:

• Coordinates of each point, or
  

• Distance – bearing of each point, starting from a known point, or
  

• Distance – bearing of each point, starting from some distance / bearing from a know point, or
  

• Distance – bearing of each point, starting from two points with their bearings,
  

• etc
  

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2. It is recommended to use the Map Maker internal text editor to enter the data:
Main menu > Utilities > Text editor > Select type: Map Maker survey data (.xy) > Select folder > Specify file name for new file > Save
Alternatively, you can use WordPad, Notepad or any other text (ASCII) editor.

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2.A) If you have the coordinates of each point of a polygon or line, enter each point (1,2...n) with its x and y coordinates in one line, separated by comma, and the name of the unit in the first line. The syntax reads as:

Name of polygon,x1,y1
x2,y2
x3,y3
…
xn,yn

For example (see below):

MyPlot, 814179,617801
814201,618242
815219,618581
814563,617518
814179,617801

If the last point is equal to the first point, it will be a polygon, otherwise a line.

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2.B) If you draw a polygon or line starting from a known point (1), with all next points surveyed the old-fashioned way through distance – bearing (2,3…n), the syntax is:

COMPASS TRAVERSE
Name of line,x1,y2
bearing1,distance1
bearing2,distance2
…
bearing n,distance n


For example:

COMPASS TRAVERSE
MyOtherPlot, 814179,617801
90,45
175,32
261,35

If the last line segment reaches the starting point, it will be a polygon, otherwise a line. In practice, there will be a discrepancy. If you add the word CLOSE to the bottom, Map Maker will spread the error proportionally among the other points in the polygon.

For example:

COMPASS TRAVERSE
MyOtherPlot, 814179,617801
90,45
175,32
261,35
CLOSE

See Annexes 16.2 and 16.3 for full description and samples of the traverse methods.

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2.C) If you draw a polygon or line starting from a point (2), which has a know distance – bearing from a known point (1), with all next points surveyed through distance – bearing (3,4…n), the syntax is:

POLAR,x1,y1
Name of line,bearing2,distance2
bearing3,distance3
bearing4,distance4
…
bearingn,distancen

If the last line segment reaches the starting point, it will be a polygon, otherwise a line.

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2.D) There are more entry options. See the documentation in the official manual of Map Maker or contact LUPMIS. See also Annexes  16.2 - 16.5 for samples.

• Compass bearing method: Distance-bearing readings for all points of a surveyed polygon, starting from two reference points known by their x-y-coordinates
  

• Relative angles method: Same as above, but the first point of the surveyed polygon is measured in an angle to the base line between the two reference points (not in North bearing)
  

• Relative polar coordinates method: Same as above, but all angles are in reference to the base line between the two reference points (not in N bearing)
  

• Distance method: Only the distances of all points of the surveyed polygon from the two reference points are used, no bearings at all.
  

• Angle traverse method: Similar to the compass traverse method (see para 2.B above), but all angles are relative to the previous angles, not in North bearing.
  

• Offset method: An object is defined by its 90º offset from a point on a straight line between the two reference points
  

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3. Press <Enter> at the end to close the last line.

Having entered all data, you must save the file (File > Save > OK)

Be sure, that the saved file has the extension XY, not TXT.


4. Use the import facility of Map Maker:
Main menu > Utilities > Vector utilities > Import files > Map Maker survey (*.XY) > Import Map Maker survey data, step 1 window: Choose source XY file > Select folder and file > Open > Next step > Step 2 window: Choose target file > Specify file name > Save > Finish > Do you want to check polygon topology: Yes > Confirm save

The new DRA file can now be displayed and processed.

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LUPMIS exercises:
1. Modern surveyors use high-accuracy GPS to survey a parcel. They came back from the field with following coordinates: 780491/611165, 780517/611170, 780523/611133, 780497/611129. Transfer to Map Maker and display with background orthophotomap (if available).
2. Old survey reports show following distance-bearings for a parcel: 171.0º/36.65m, 260.3º/26.45m, 351.3º/36.49m, 79.9º/26.30m, with start at 780517/611170. Transfer to Map Maker.
3. How do these two plots compare?
4.Prepare a draft survey report of this parcel (UPN 780-0611-0053).
5. Another exercise: The surveyed plot has following distance-bearings, starting at x 784791, y 607700: 90º, 100m - 180º,50m - 90º,50m - 180º,100m - 270º,150m. What is the last line to close the parcel? Transfer to Map Maker.