3.1 Opening NADCON |
· Workstation version: Double-click the NADCON 4.2 icon located on the desktop. If the icon has been removed from the desktop, go to Start > Programs > NADCON. The following main screen is displayed when the program is launched from the locally-installed copy on the workstation:
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3.2 Converting Data Points – General Information
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NADCON can convert either a single coordinate point or multiple geographic coordinates stored in one of the supported file formats. Entering values in the Input Latitude/Longitude fields causes the program to perform a single point conversion. Refer to section 3.3, “Converting a Single Data Point”. Entering values in the File Format, Input File, and Output File fields causes the program to perform file based conversion. Refer to section 3.4, “Converting Multiple Data Points”. The file formats are explained in detail, including instructions for converting multiple data points.
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New Graphic User Interface simplifies the conversion process.
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Figure 3-3: Main Form: Converting a Single Data Point versus Multiple Data Points
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3.3 Converting a Single Data Point
Multiple display formats are available.
Coordinates MUST have a decimal point in both the Latitude and Longitude values. |
3.3.1 MethodTo convert a single geographic coordinate point, use the Input Latitude and Longitude fields. 1. Select the Datum Transformation from the pull-down menu. 2. Enter the coordinate values into the Input Latitude and Longitude fields. Coordinates can be in one of three formats:
Note: NADCON will recognize if the numbers/data entered do not meet required parameters. If a field turns yellow after the user tabs out of the field, this is an indication that the data does not fit the required format and must be revised. Holding the mouse pointer over the highlighted field (hovering) will display a brief description of the error. If the user still attempts to perform the conversion, NADCON will provide an error message. 3. Choose the Display Format by clicking one of the radio buttons. Important Note: This choice determines the way that the
output is displayed, regardless of the input format. This setting affects the on-screen display as well as the conversion summary report, but does not affect the values written to the supported file formats. For example, if a user enters a coordinate in DD MM SS format and the Display Format selected is DD.DDD, the NADCON program will accept the field input, validate it as a geographic value, and immediately reformat it in the decimal degrees format. 4. Click Display Conversion Report if a report is desired. The report will be displayed on the screen after all conversions are complete. This file is in an ASCII text file format and can be saved, if desired, using the normal “File-Save” method for your text file viewing application. Refer to “Viewing Conversion Statistics Reports.” 5. Click the Perform Conversion button. The results of the conversion will be displayed on the screen. The output will contain the latitude and longitude of the converted coordinate point, as well as the latitude and longitude shifts in arc seconds and meters, and the total shift in meters. 3.3.2 Coordinate Formats· General Information: - Three Formats may be used: decimal degrees; degrees and decimal minutes; and degrees, minutes, seconds. - The decimal is important! NADCON uses the location of the decimal to determine the format of the input. If no decimal is present, an error message will be displayed. · Decimal Degrees: - This format treats the coordinate as a signed floating point value. Latitudes may be between -90.0000 and 90.0000. A positive value indicates north latitude. A negative value indicates south latitude. Longitudes may be between -360.00000 and 360.0000. Any number of decimal places may be specified. A positive value indicates an east longitude. A negative value indicates a west longitude. A longitude greater than 180 and less than 360 indicates that the program will treat it as “wrapping around” to the other hemisphere. Therefore longitude 185 west will be treated as 175 east. - Alternatively, the hemisphere may be indicated by an alphabetic indicator. Enter “E” for east or “W” for west longitude. Enter “N” for north, “S” for south latitude. The hemisphere indicator can be placed either before or after the numeric value. Following are examples of valid values in this format: Latitude Longitude 39.718 -78.234 39.718N 78.234W S23.4055 165.3223- · Degrees and Decimal Minutes: - The latitude value is entered as an integer from -90 to 90 followed by one or more spaces. The longitude value is entered as an integer from -360 to 360 followed by one or more spaces. Following the space, the minutes value is entered as a floating point value ranging from 0.0000 to 60.0000, for both latitude and longitude. Any number of decimal places may be specified. A positive value indicates north latitude or an east longitude. A negative value indicates south latitude or a west longitude. - Alternatively, the hemisphere may be indicated by an alphabetic indicator either before or after the numeric value. Enter “E” for east or “W” for west longitude. Enter “N” for north, “S” for south latitude. The hemisphere indicator can be placed either before or after the numeric value. Following are examples of valid values in this format: Latitude Longitude 39 23.718 -78 10.234 39 23.718N 78 10.234E S23 39.4055 165 0.3223- · Degrees, Minutes, Seconds: - In this recognizable, classic format, the latitude value is entered as an integer from -90 to 90 followed by one or more spaces. The longitude value is entered as an integer from -360 to 360 followed by one or more spaces. Following the space, the minutes value is entered as an integer between 00 and 59, again followed by a space, and finally followed by a floating point seconds value ranging from 0.0000 to 60.0000. A positive value indicates north latitude or an east longitude. A negative value indicates south latitude or a west longitude. - The rules for entering the hemisphere indicator are the same as for the other two formats above. Following are examples of valid values in this format: Latitude Longitude 39 23 10. -78 10 45.234 39 23 10.000N 78 10 45.234E S23 39 52.4055 165 0 0.- 3.3.3 Using the ClipboardNADCON allows the user to copy a coordinate into and out of the NADCON Main Form. Several options are available from the “Edit” menu:
lat-sec. 0.7178 lon-sec. 2.13052 lat-m. 22.12237 lon-m. 53.62802 tot-m. 58.01176
Important Note: Pasting from the clipboard means pasting a latitude and longitude in a “freeform” format. When performing the paste operation, NADCON will interpret the values as if they were freeform text, will separate the latitude and longitude values, and will place them into the correct fields on the main form. However, the latitude and longitude values must still conform to the requirements for coordinate formats explained in “Coordinate Formats”.
Important note regarding edit functions: The purpose of the edit function shortcuts is to make handling latitude/longitude pair values in text format a little quicker and easier. The standard system edit functions (i.e., "Paste" function, using the ctrl-v keyboard shortcut) still work as expected for all fields on the form.
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3.4 Converting Multiple Data PointsMultiple data points can be converted by using files containing sets of coordinate points: •Free format 1 •Free format 2 •NGS Horizontal Bluebook •ESRI Shapefile •ESRI World File
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3.4.1 Method1. Select the Datum Transformation from the pull-down menu. 2. Select the File Format by choosing the appropriate radio button. For more information about file format, refer to “File Format Descriptions”. 3. Select the input file for conversion by clicking the Browse button next to the Input File field. The program will display an Open dialog box, which allows the user to pick the file. If desired, the user may also type the full path to the data in this field. 4. Select the location (folder) to which the output file should be posted by clicking the Browse button next to the Output File field. Additionally, an output file name MUST be specified. If the Output File field and file name have not been chosen, NADCON will not attempt to perform the conversion. 5. If a report is desired, click Display Conversion Report. The report will be displayed on the screen only. If the file to be converted contains more than 1000 points, the conversion report will not be generated. Note: The displayed conversion report will be an ASCII file. If desired, it may be saved using the Notepad “File-Save” menu options. 6. After the file names have been entered, click the Perform Conversion button at the bottom of the form. NADCON will then execute the necessary actions to perform the interpolation function and will save the results in a file to the location specified. 7. The output can be viewed by navigating to the output file specified. 3.4.2 File Format DescriptionsThere are five major types of file formats accepted by NADCON. NGS Horizontal Bluebook - Latitude and longitude in NGS Horizontal Blue Book *80* record format. Only the latitude and longitude in the record are modified, leaving the rest of the record unchanged. - For more information refer to “Input Formats and Specifications of the National Geodetic Survey Data Base”. The *80* format is described on pages 2-77 and 2-78 in Chapter 2: “Horizontal Observation Data”.
Free Format 1 and Free Format 2: - ASCII text files consisting of latitude and longitude point definitions. - Latitude and Longitude: ◦ Free Format 1 - latitude and longitude in columns 41-80 ◦ Free Format 2 - latitude and longitude in columns 1-40 In both of these formats, there will be 40 columns of unused space on one side or the other. If desired, the user can type a station name or other identifying information into the unused columns. NADCON will capture this information and print it out in the report. - Both free format input types accept any supported coordinate formats, as specified in the “Coordinate Formats” section. - In the two free format input file formats, the exact column position of the latitude and longitude is not important as long as they fall within the correct range of columns. - The latitude and longitude numeric format in the two Free Format types may be expressed as: ◦ Integer degrees, integer minutes, and decimal seconds. ◦ Integer degrees and decimal minutes. ◦ Decimal degrees. - The decimal is important! NADCON uses the location of the decimal to determine the format of the input. If no decimal is present, an error message will be displayed. Raster/ESRI World File - A file format for associating geographical point data with bitmapped image files, allowing assignment of geo-coordinate information to a map or other image file. - World files consist of sets of point data consisting of six lines each, denoting the following: ◦ Line 1: (size in pixels in x direction) ◦ Line 2: (rotation term for row) ◦ Line 3: (rotation term for column) ◦ Line 4: (size in pixels in y direction) ◦ Line 5: (x coordinate of center of upper left pixel in map units) ◦ Line 6: (y coordinate of center of upper left pixel in map units) - The World file format is always associated with a bitmap or raster image file. There are many of these image formats and all will be supported by NADCON, since processing is identical for all. The image file itself is unchanged. The text file containing the geographic coordinate data is assigned a new file extension, depending on the original file type. - The following table lists the image file types and extensions recognized by NADCON:
ESRI Shapefile Geographical data file format supported by Environmental Systems Research Institute, Inc. (ESRI) software. ESRI shapefiles are composite data structures consisting of several independent data files. The two files that NADCON works with are:
1) The main file. 2) An index to the main file. Note: NADCON will only create a conversion for the main file and the index file. If copies of the other files/file types are needed to complete the shapefile structure, the user will have to make copies of the exiting files and manually rename the files to match the newly converted main file and index file. Additional Note: NADCON will not convert a geographic data point if the coordinate is located in the database (.dbf) file. A full description of ESRI Shapefiles is available at http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf.
Important note pertaining to shapefiles and world files: NADCON only works for latitude and longitude formats. It cannot convert coordinate formats/projections such as State Plane Coordinates or Universal Transverse Mercator coordinates. |
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3.5 Removing, Adding, and Main-taining Conversion Types
Conversion Types can be tailored to suit user preferences.
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3.5.1 The BasicsThe purpose of removing, adding, and maintaining datum conversion types is to allow the user to: · Add, remove, or re-order items in the Datum Transformations pull-down menu, and · Tailor the way in which the items on the pull-down menu are displayed. How is This Feature Used? The user may wish to remove conversion types not necessary for the current work at hand, thereby increasing the efficiency of the tool. If a conversion type is removed, the grid file is not physically deleted from the file system. It will still reside within the local installation folder. This allows the user to add conversion types back into the pull-down menu at a later time if desired. How to Get There To get to the Maintain Conversion Types Form, click the Add/Remove Grids button on the NADCON Datum Conversion Utility screen. The following screen will appear: Figure 3-4: Add/Remove Transformations Form 3.5.2 Adding a New Datum Transformation1. Click the New button. This prepares the screen for addition of new datum transformation grids. Note: All fields are cleared except for the Conversion ID. The program defaults the ID to the next available integer. After saving this transformation type, the user may modify this ID to control the order in which the datum transformations are displayed. Refer to “Conversion ID” below for more information. 2. Click the Browse button. A typical Windows dialog box will allow the user to navigate to the folder where the grids are located. 3. Navigate to the location of the grid files. Note: The grid files are in pairs that have extensions of “.las” and “.los”. Both files in a pair must be present in order to function. These files are located in the program installation directory in a folder called “grids”. Only the files having the “.los” extension will be visible. 4. When the “.los” file of the grid pair is located, highlight the file and click OK. The program will automatically pull the file into the “Add/Remove Transformations” form. The .las and .los extensions will be stripped off in the display. 5. The other details – shift direction and description – can then be filled in. See “Tailoring the Appearance or Order of a Conversion Type”. 6. Save the change:
Note: Clicking on the Cancel All Changes and Close button reverts the “in-memory model” so that it matches the last saved Datum Transformation file. 3.5.3 Removing a Datum Transformation1. Select the Datum Transformation from the pull-down menu. 2. Click Remove. Note: The user will be required to validate the choice by responding to a “Please confirm this action” screen. Select Yes or No as needed. 3. Save the change:
Note: Clicking on the Cancel All Changes and Close button reverts the “in-memory model” so that it matches the last saved Datum Transformation file. 3.5.4 Tailoring the Appearance or Order of a Datum TransformationThe user may wish to change the way in which a conversion types appears on the pull down menu. To do so, refer to the following: The Datum Transformation dropdown displays the same list of supported conversions as on the main screen. The user may use it to select an existing conversion type that he or she wishes to modify or remove. The Conversion ID field displays and allows modification of the assigned integer ID. This allows the user to control the order in which the supported conversion is presented. If the user enters an ID already in use, the existing records are renumbered so that entries with a larger ID are “shifted down” in the display order. The Shift Direction field is a pull-down box which allows the user to select whether a conversion using this conversion grid is performed from an older datum to a newer one or from a newer to an older. The Description field allows the user to enter or modify descriptive information for a Datum Transformation field. This description is also used in the title of the Conversion Statistics Report. The Grid File Path displays and allows the user to enter or modify the file system path where the “.las” and “.los” files stored. The grid file path also contains the name of the file. The browse button presents a folder browse dialog box to allow the user to navigate to the file. The “.las” and “.los” extensions are stripped from the display but both files are used by the program.
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3.6 Viewing Conversion Reports
Output information is available in summary form, which includes a graphic representation
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3.6.1 Conversion Detail ReportFor each conversion performed, the NADCON application will create a detail report displaying information for the conversion operation. If the button Display Conversion Report was chosen, the report can be viewed on–screen. A sample of the report follows: Figure 3-5: Conversion Detail Report As illustrated above, the detail report will display - for each geographic point in the input file - a description of the conversion operation, including the following data items (refer to the numbered labels above): 1. Transformation #: A simple sequential count of transformations. 2. Station Name: The user-supplied identity of the geographic station name. 3. Original Values: The Latitude and Longitude of the input geographic point. Lat/Long point values are presented in the display format selected by the user on the NADCON main form. 4. Converted Values: The results of the NADCON conversion operation.
5. Shift Values: The distance of the NADCON conversion shift in both seconds and meters in both the east/west and north/south directions. 6. Magnitude of Total Shift: The total distance of the shift.
3.6.2 Conversion Summary ReportAfter all conversions are complete, the NADCON application will create a detail report displaying statistics for all conversions performed during a single operation. NOTE: The summary report will only be created if there is more than one point converted. Additionally, if there are more than 1000 points to be converted, this report will not be produced. A sample of the report follows: Figure 3-6: Conversion Summary Report As illustrated above, the summary report will display, for the total of all points converted, the totals of all conversion operations, including the following data items (refer to the numbered labels above): 1. Range of shift (meters): For both latitude and longitude, the smallest and largest shift performed, in meters. 2. Range of shift (seconds): For both latitude and longitude, the smallest and largest shift performed, in arc seconds. 3. Summary for mean, variance, and standard deviation in meters: For both latitude and longitude, general statistics in meters. 4. Summary for mean, variance and standard deviation in seconds: For both latitude and longitude, general statistics in arc seconds. 5. Total number of conversions: Total count for all conversion operations. 6. Region of Conversions: A graphic representation/diagram illustrating the minimum and maximum latitude and longitude for all conversions in the group. 3.6.3 Conversion Summary Error ReportsThere are two main types of conversion summary errors that can occur during the NADCON conversion. The first error type is one that occurs when input data does not pass validation rules. This applies to either the user entered parameters on any of the program forms, as well as data in input files. The second error type occurs when an environmental or program logic error occurs. In both cases, a form, report or message will be displayed containing some or all of the following information as appropriate (actual appearance may vary based on the run-time context). Note: Prior to pressing the Perform Conversion button, NADCON will recognize if the numbers/data entered do not meet required parameters. If a field turns yellow after the user ‘tabs out’ of the field, this is an indication that the data does not fit the required format and must be revised. Holding the mouse pointer over the highlighted field (hovering) will display a brief description of the error. If the user still attempts to perform the conversion, NADCON will provide an error message. Following is a sample of a conversion summary error report: Figure 3-7: Conversion Summary Error Report
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3.7 Help |
Help for NADCON is available by using the Help menu at the top of the NADCON Main Form. The help menu topics correspond with this User Manual. The help menu also has short-cut keys: § Alt+1: What Is NADCON § Alt+2: NADCON Features § Alt+3: Using NADCON § Alt+4: Troubleshooting § Alt+5: Technical Information § Alt+6: Additional References Context-specific help is also available by placing the cursor in a field (or using the tab key to move the focus to the screen control of interest) and pressing the F2 key. |