GPS- Collecting Data

Geo II ch 5Edited 10/14/05

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GPS- Collecting Data

Now that you have your data dictionary loaded, let’s configure the unit and take it outside!

RECOMMENDED: Print this & take it outside with you!

Geo II ch 5 Edited 08/25/04

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First thing that we need to do is to restore the factory settings on the rover. This step should not be performed on a unit already in use in another project as loss of data, data dictionary and settings will occur.

1. Turn the rover on. You should come to the “Main Menu” screen.

2. Using the arrow buttons to move you around, scroll down to highlight “Configuration”. Push the “diamond” or “Enter” button to select.

Restoring Factory Settings


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The screen should now look like this:

Restoring Factory Settings

3. Using the arrow buttons again, scroll down and select “Fact. Defaults”. Push “Enter”.

4. Use the arrows to highlight “Set Defaults” and push “Enter”.

5. Press “Enter” once again to confirm your decision.


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Your screen should look like this. This tells us that the defaults have been restored. To exit from this screen, push the “Esc” button until you are back to the main screen.

Now, we’re ready to collect data!


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Before you go out into the field to collect data you need to be a little familiar with the data that you want to collect.

The following slides have all of the features and their attributes that you need to collect while in the field.

Feature: something that can be mapped using the GPSe.g. walkway, building, athletic field

Attribute: information about a feature e.g. Walkway Width (feet) = “4”

Building Name = “Main Office”

Athletic Field Type = “Baseball”


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Buildings (polygon)Name (text: type in the name of the building)Function (menu: choose academic; administration; or athletic)

Athletic Field (polygon)Type (menu: choose football; baseball; or intramural)Name (text: type in the name of the athletic field)

Flagpole (point)Responsibility (menu: choose student body; administration; student organization; or other)Height (number: type in the height of the flagpole in feet)Construction (menu: choose aluminum; steel; wood; or other)Condition (menu: choose good; fair; or poor)

Walkway (line)Surface (menu: choose concrete; gravel; or asphalt)Width (number: type in the width of the walkway in feet)

Bleachers (polygon)Function (menu: choose athletic; assembly; performance; or other)Construction (menu: choose wood; aluminum; or other)Portable (select Yes or No)

Parking Lot (polygon)Surface (menu: choose asphalt; concrete or grass)Use (menu: choose multiuse; students; or faculty)

This is a very useful page

while you are outside

mapping your school.

These are the features that you will collect and their attributes.


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Before you collect your data(Hints for easier data collection)

You can collect more than one feature in any rover file: (e.g. 3 athletic fields, 10 buildings, 14 walkways, 2 flagpoles, and 5 parking lots)

These can all be contained within one rover file. However you may not be able to map your entire school in one EAST class:

Therefore you need a plan of action:

Collect one type of feature (e.g. all walkways) within one EAST class and move onto another feature type in your next EAST class.

For example:First EAST class: collect all of the parking lotsSecond EAST class: collect all of the athletic fields

And so on until you have collected all of the features in your school.

You can transfer each individual rover file to your PC before you begin thenext rover file. (see Ch 6: transferring GPS data)


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Now we are ready to take our GPS outside!

Getting Satellites

6. From the Main Menu, select “GPS Status”.

7. Now, select “Sat Tracking”. We should now be at this screen.

It tells us what satellites the rover sees, and how many it has been able to lock. Each arrow represents a satellite whose location has been confirmed. The objects in the bottom left corner of the screen are also indicators.


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Note: You need to be outside for the GPS to “see” any satellite vehicles (SVs).

If you are outside and the PDOP is above 6, then you may not be holding the rover correctly:

Getting Satellites

Your screen may look like this, or it may have writing across the bottom that reads “PDOP”.

A high PDOP means that our satellites are not in a good geometry for accurate readings.

Once you have reset the factory defaults on the rover, the limit for PDOP is 6, so anything above this will not allow us to collect positions.


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wrong

right

wrong

Holding the Rover

Your body can block satellite signals, so it is important to hold the GPS rover correctly.

For the best reception:• Hold the rover away from your body.

• Tilt it so that the top of the GPS (the antenna) is parallel with the ground.

•Hold it up so that you and the satellites can see it. Keep in mind that your friends can block signals too, so don’t let them crowd you.

It may also take a few minutes to get a good set of satellites – especially if the rover has been inside for a long time or has never been turned on.


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Getting Satellites

Notice here that by standing in the right position, our PDOP has dropped from 6.97 to 3.89. We picked up a new satellite that was in a better position to give us good readings.

Now, we can collect points!

If at any time you notice that your counter is not moving, you can get to this menu from the Data Collection screen by selecting “Main Menu” and then “GPS Status”.


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Data Capture Screen

8. Push “Esc” to get back to the “Main Menu”. Then, use the arrows to scroll to “Data Capture”, and push “Enter”.

9. Scroll down to “Dictionary” and push “Enter”.

10. The dictionary loaded should be “schoolmap”. If it is not, delete the other dictionary and reload “schoolmap” in the lab.


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Opening a New File

11. Push “Esc” to bring you to the “Data Capture” screen.

12. Use the arrow keys to scroll down to “Open Rov. File” and push “Enter”.“Rov.” stands for “Rover” (as in GPS Rover).

13. Scroll down to “Pause” in the Rover File options and push “Enter”. This will pause the rover so that we will be able to enter in attributes before collecting any location data.


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PLEASE remember that you can collect more than one feature within a rover file!

Selecting a Feature

14.Scroll down to “Select Feature” and push “Enter”.

Here, you see a listing of types of features that you can collect when you are out in the field. You have a choice of five features, three are polygons, one is a line and one is a point.

This tutorial will walk you through collecting one athletic field and one flagpole.

Be aware that that there are a couple of different methods for collecting features. You should be familiar with these before going out to collect data.


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Collecting Data – Athletic Field

To collect an athletic field feature go to the actual field that you are planning on mapping.

15.Scroll down to “Select Feature” and push “Enter”.

Now, we see a list of all of the possible features that we can collect.

15.Scroll down to “athletic_field” and push “Enter”.

16.Scroll down to type of field, and push “Enter”.


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Adding and Changing Attributes

17.This is a menu list of types of fields. Select the type of field that you are about to map by scrolling down and pushing “Enter”, when the field type is highlighted.

18.When you have done this, it brings you back to the screen with both “type” and “name” listed.

19.Select “Name” and push “Enter”. The screen should look like this: You will fill in the data on this line. Select this dotted line and push “Enter”.


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Adding and Changing Attributes

20. Using your arrow buttons, scroll up and down through the alphabet to select your letters. When you have the correct letter, push the right arrow button to move over one space.

21. When you have completed naming your field, push “Enter” again to get to the previous screen.


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The unit is still paused, and no points have been collected. Walk to the corner of the field.

22. If your field is rectangular, you can get the straight sides by collecting points only at the corners. To do this, select “Resume”. This is how you can start and pause the collection of data.

23. Watch the counter in the corner. Collect one position, and then push “Pause” again to pause the collection.

24. Do this for each corner, selecting “Pause” at the last corner.


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25. When you are done, select “Close Feature” to close the feature. You should be back to the “Select Feature” menu.

You should be back to the “Select Feature” Screen.

You have collected one athletic field feature.


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Collecting Polygon or Line features

PolygonsYou can start collecting and walk around the feature, collecting data continuously. This is best for curvy features (like a baseball field).

or You can collect just the corners, using the log button to pause in between point collection. This is best for rectangular features like a building or football field.

The GPS will automatically close the polygon for you (so you don’t need to go back to your starting point).

Hint: Line features are collected in the same way as polygons, except that the GPS doesn’t close the polygon.

Lines For curvy sidewalks collect data continuously.Straight walkways: collect data at the corners, pausing the unit in between point collection.


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Collecting Data - Flagpole

26. Walk to your school’s flagpole. On your GPS scroll down to “flagpole” and push “Enter”. As long as you ended the collection of the field in the paused mode, your unit should still be paused. If it isn’t, select “Pause”.

27. Add in the attributes for responsibility (who is in charge of putting up and taking down the flag).

Now we are going to collect a point feature – your school’s flagpole.


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28. Scroll down to “height” and push “Enter”.

29. The default for “height” is 50 feet. Use your up and down arrow buttons to change this number to the height of your flagpole. When you are finished, push “Enter”.

30. Finish adding attributes. When you are done, select “Resume” to start collecting data.

31. To collect a point, you need to stand still until your counter reaches 120 points. When you have done this, push “Close Feature”.


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Now you should be familiar with collecting features using your GPS. You should be able to map your entire school, using the methods that have been given as an example in the previous slides.

Remember: that you can collect more than one type of feature within a rover file.

After you have finished collecting all of the features that you can in the time allowed you can close the rover file and take the GPS back inside to transfer the data to your PC.

You may need to make multiple data collection trips to map your whole school – so plan what you are going to collect before going outside! (see slide 6).

Collecting Point features

Points: When collecting points, the GPS will take an average location based on the number of points you collect (when collecting the flagpole you need 120 points, collecting 1 point each second, therefore you have to stand still for 2 minutes).


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Closing your file

Once you have finished collecting all of your features that you can in the time allowed you can close your rover file.

32.Select “Close File” and push “Enter”.

33.Confirm closing the file by selecting “Yes” and pushing “Enter”.

34.Push “Esc” to get out of the data collection and back to the main menu. The file has been stored, and you can now take it back inside.

Chapter 6 will describe how to transfer your GPS data to your computer.

GPS- Collecting Data

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