The cartographic software package Map Maker has a set of strong features that make it ideal for handling field survey data. In this document the usage of some of these features is explained in the form of a one-page example for each. In writing these examples the author has borrowed freely from the section of the Map Maker manual dealing with surveying data and herewith acknowledges his debt. This document is not intended to be a substitute for the official manual, which covers all of the features of Map maker. The illustrations in the PDF version of this document carry a fair amount of detail and may be enlarged in Adobe Reader by pressing the ‘+’ button or by holding down the ‘Ctrl’ key and rotating the mouse wheel. The one-page examples written so far are for surveying by: • Closed compass traverse (Page 2). • Open compass traverse (Page 3). • Offsets (Page 4). • Distances from fixed points (Page 5). The author would be grateful for any comments, suggestions or special requests on how this document might be improved, no matter how trivial. The document has no copyright and is entirely in the public domain. Copies of the pages can be supplied in the original SVG format, on request. [email protected]The most recent version of the document will always be available at http://confound.me.uk/Surveying/survey_by_example.pdf 1
Transcript
Plotting survey data in Map Maker
The cartographic software package Map Maker has a set of strong features that make it ideal forhandling field survey data. In this document the usage of some of these features is explained inthe form of a one-page example for each.
In writing these examples the author has borrowed freely from the section of the Map Makermanual dealing with surveying data and herewith acknowledges his debt. This document is notintended to be a substitute for the official manual, which covers all of the features of Map maker.
The illustrations in the PDF version of this document carry a fair amount of detail and may beenlarged in Adobe Reader by pressing the ‘+’ button or by holding down the ‘Ctrl’ key androtating the mouse wheel.
The one-page examples written so far are for surveying by:
• Closed compass traverse (Page 2).
• Open compass traverse (Page 3).
• Offsets (Page 4).
• Distances from fixed points (Page 5).
The author would be grateful for any comments, suggestions or special requests on how thisdocument might be improved, no matter how trivial. The document has no copyright and isentirely in the public domain. Copies of the pages can be supplied in the original SVG format,on request.
Set a marker on the ground at Point A. From Point A take a compass bearing on Point B, then measure the distance between Point A and Point B. From Point B take a compass bearing on Point C, then measure the distance between Point B and Point C. Repeat for the remaining legs of the polygon, ending at the starting point.
Record the results of the survey in a data table similar to that shown. The bearings shown in the table of survey data are grid bearings. Magnetic compass bearings must be converted to grid bearings by compensating for local magnetic variation. If magnetic north is west of grid north in the area of the survey the variation is deducted from the magnetic bearing. If magnetic north is east of grid north in the area of the survey the variation is added to the magnetic bearing.
Making an XY file: In Map Maker, go Utilities ► Text editor, from 'Save as type' select 'Map Maker survey data (*.xy)'. Give the file a name and select a folder for its storage. Then click 'Save'. Now enter the survey data in the form shown in the picture. When finished, go File ► Save ► OK.
Making a DRA file: In Map Maker, go Utilities ► Vector utilities ► Import files ► Map Maker survey (*.XY). In the box that pops up click on 'Choose source XY file'. Navigate to the folder containing the XY file, select it and click on 'Open'. Click on 'Next step', accept the target file name offered and click 'Finish'. In the 'Confirm' box that appears click 'Yes', then click 'Confirm save'.
Loading a DRA file: In Map Maker, go File ► Add layer, then navigate to the folder containing the DRA file, click on it and then click 'Open'. Select a style and then click 'OK'.
The XY File
The product of a closed compass traverse is always a polygon. The corners of the polygon may represent points whose positions it is wished to plot, or the polygon may enclose a landscape feature (as it does in the example provided). The magnitude of surveying errors may be assessed by plotting the polygon in Map Maker without using the 'CLOSE' statement in the XY file, see below.
Finished DRA File in Map Maker
When plotted the survey data should describe a polygon that closes perfectly. In practice this never happens, there is always an 'error of closure', a gap between the starting point and the ending point of the polygon.
The 'CLOSE' statement is used here to tell Map Maker to close the polygon. Map Maker does this by sharing the error of closure between all of the corners of the polygon. It is good practice to check the geometry of polygons by first plotting them without using the 'CLOSE' statement. This will allow the magnitude of the inevitable surveying errors to be assessed.
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GRIDNORTH
Set a marker on the ground at Point A. From Point A take a compass bearing on Point B, then measure the distance between Point A and Point B. From Point B take a compass bearing on Point C, then measure the distance between Point B and Point C. Repeat for the remaining legs of the traverse.
Record the results of the survey in a data table similar to that shown. The bearings shown in the table of survey data are grid bearings. Magnetic compass bearings must be converted to grid bearings by compensating for local magnetic variation. If magnetic north is west of grid north in the area of the survey the variation is deducted from the magnetic bearing. If magnetic north is east of grid north in the area of the survey the variation is added to the magnetic bearing.
Making an XY file: In Map Maker, go Utilities ► Text editor, from 'Save as type' select 'Map Maker survey data (*.xy)'. Give the file a name and select a folder for its storage. Then click 'Save'. Now enter the survey data in the form shown in the picture. When finished, go File ► Save ► OK.
Making a DRA file: In Map Maker, go Utilities ► Vector utilities ► Import files ► Map Maker survey (*.XY). In the box that pops up click on 'Choose source XY file'. Navigate to the folder containing the XY file, select it and click on 'Open'. Click on 'Next step', accept the target file name offered and click 'Finish'. In the 'Confirm' box that appears click 'Yes', then click 'Confirm save'.
Loading a DRA file: In Map Maker, go File ► Add layer, then navigate to the folder containing the DRA file, click on it and then click 'Open'. Select a style and then click 'OK'.
Point Ax = 431086y = 380778
START
Leg Bearing Metres
(A) to (B) 45.7 61.5
(B) to (C) 22.2 58.3
(C) to (D) 0.0 54.3
(D) to (E) 38.3 36.6
(E) to (F) 76.2 44.6
(F) to (G) 112.3 51.4
Table of Survey Data
A
B
C
D
E
F
45.7°
61.5
22.2°
58.3
0.0°
54.3
38.3°
36.6
76.2°
44.6112.3°
51.4
G
Centreline of path
Finished DRA File in Map MakerThe XY File
The product of an open compass traverse is always a polyline. The corners of the line may represent points whose positions it is wished to plot, or the polyline may describe the shape of a linear feature. In the example provided the polyline is taken to represent the centreline of a path.
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Making an XY file: In Map Maker, go Utilities ► Text editor, from 'Save as type' select 'Map Maker survey data (*.xy)'. Give the file a name and select a folder for its storage. Then click 'Save'. Now enter the survey data in the form shown in the picture. When finished, go File ► Save ► OK.
Making a DRA file: In Map Maker, go Utilities ► Vector utilities ► Import files ► Map Maker survey (*.XY). In the box that pops up click on 'Choose source XY file'. Navigate to the folder containing the XY file, select it and click on 'Open'. Click on 'Next step', accept the target file name offered and click 'Finish'. In the 'Confirm' box that appears click 'Yes', then click 'Confirm save'.
Loading a DRA file: In Map Maker, go File ► Add layer, then navigate to the folder containing the DRA file, click on it and then click 'Open'. Select a style and then click 'OK'.
The XY File Finished DRA File in Map Maker
The product of a survey carried out by offsets is a polyline whose corners, A to M in the example, might represent points whose positions it is wished to plot or points on a linear feature. In this example the feature under survey, represented by a broken black line, might be thought of as the edge of a stream.
Markers are placed at Station 1 and Station 2, and their positions are determined. The line connecting Station 1 and Station 2 is the baseline for the survey.
Offsets are measured at intervals from the baseline to the feature under survey. The offsets must be at right-angles to the baseline. In the example, the first offset starts at a distance of 19.2 metres from Station 1 and is 25.9 metres long. The second offset starts at a distance of 34.9 metres from Station 1 and is 47.4 metres long, and so on for the remaining offsets.
Record the results of the survey in a data table similar to that shown below.
In the example shown, when viewed from Station 1 looking towards Station 2 the baseline has been set out to the left of the feature being surveyed. When a baseline is set out to the right of a feature (when viewed from Station 1 looking towards Station 2) the lengths of the offsets must be entered into the XY file as negative numbers.
The product of a survey carried out by measuring distances from two fixed points can be a polyline or a polygon. Map Maker will draw a polygon if the last coordinate in the XY file is the same as first one, as it is in the example. If the first and the last coordinates in the XY file are not identical a polyline will be drawn.
In the example the feature under survey is to the right of a line connecting Station1 to Station 2, when viewed from Station 1. In cases where the feature under survey lies to the left of a line connecting Station 1 and Station, when viewed from Station 1, the distances measured must be entered into the XY file as negative numbers.
Set out two markers on the ground, Station 1 and Station 2, at points of known position. Then measure the distance from each station to Point 1. Repeat for the remaining points and record the survey data in a table similar to the one shown.
The XY File Finished Polygon in Map Maker
Making an XY file: In Map Maker, go Utilities ► Text editor, from 'Save as type' select 'Map Maker survey data (*.xy)'. Give the file a name and select a folder for its storage. Then click 'Save'. Now enter the survey data in the form shown in the picture. When finished, go File ► Save ► OK.
Making a DRA file: In Map Maker, go Utilities ► Vector utilities ► Import files ► Map Maker survey (*.XY). In the box that pops up click on 'Choose source XY file'. Navigate to the folder containing the XY file, select it and click on 'Open'. Click on 'Next step', accept the target file name offered and click 'Finish'. In the 'Confirm' box that appears click 'Yes', then click 'Confirm save'.
Loading a DRA file: In Map Maker, go File ► Add layer, then navigate to the folder containing the DRA file, click on it and then click 'Open'. Select a style and then click 'OK'.
