PROCEEDURES LIBRARY FOR

NISQUALLY NWR WEST BLUFF

VEGETATION MAPPING AND ANALYSIS PROJECT

Prepared for:

Dr. Buckley

Geography 452

Advanced GIS

Presented by:

Molly Hanson

(smolly92@yahoo.com)

and

Chris Thayer-Snyder

(chrissnyder42@hotmail.com)

June 7th, 2000

TABLE OF CONTENTS

DATA ACQUISITION

GPS Data Collection Using the GeoExplorer III GPS

GPS Data Conversion Using Pathfinder Office

Acquisition of 24k DRG Via-Internet

Using FTP to Download Data

Decompressing Data Files Using WinZip

DATA MANIPULATION

Using the Projector! Extension

Clipping Images Using the Spatial Analyst Extension

Using the Imagewarp Extension

Updating Area, Perimeter, Acres, and Length Using the Xtools Extension

Using the Erase Tool to Create New Themes Using the Xtools Extension

GPS DATA ANALYSIS

Converting Polygon Vertexes to Points Features

Converting Polygon Features to Point Feature Constituents in Pathfinder Office

Adding X and Y Coordinates to Point Features

Determining Offset Distance Between Points (X and Y Coordinates)

Determining Area and Perimeter of Polygon Themes

Field Collection of Point, Line, and Polygon Features Using the Trimble GeoExplorer III GPS

Purpose: To collect raw GPS field data that will latter be converted to ESRI shapefiles.

Necessary Equipment: A Trimble GeoExplorer III GPS

Preconditions: Collected feature data will be post processed with corrected base station or CORS data.

The Basics:

• The GeoExplorerIII has three main menus:

1. SYS(tem) – used primarily for configuration of the GPS settings.
2. DATA – used primarily for collecting and describing feature data.
3. NAV(igate) – not used in this procedure, but is primarily for mapping and graphical orientation.

• Each of the three menus has several "sub-menus" described below:

• Each "sub-menu" has many "sub-sub-menus".
• The ENTER button enters you into sub-menus.
• The CLOSE button backs you out of sub-menus. VERY IMPORTANT! Press the CLOSE button if you get stuck or lost within all the sub-menus.

Initial Setup:

1. Turn the GPS unit on:

• Push the black oval button on the lower right.
• In five seconds the SYS(tem) GPS menu will come up - this is the default menu.

1. The GPS must be configured to the proper settings:

• Push the SYS button until you come to the "setup" menu.

1. 1. The GPS must be configured so that it can accept differential post processing and so that it records features for an appropriate length of time (depending on the feature and detail).

1. 1. Scroll down to the "feature settings" menu, and press ENTER
   2. Scroll down to "generic" and press ENTER
   3. Select "Point" and press ENTER
   4. Select "Interval" and press ENTER
   5. Scroll to the numeric value and press ENTER
   6. Select an appropriate time interval (we had ours set for 5 seconds).
   7. Press CLOSE
   8. Scroll down to "Accuracy" and press ENTER
   9. Select "Carrier" and press ENTER
   10. Point features have now been configured to accept differential post processing. Repeat steps 3 – 5 for the "Line" and "Area" features.

1. 1. Back in the "Setup" menu, select "Configurations" and press ENTER
   2. Select "Coordinates" and press ENTER
   3. Scroll down to "Altitude units" and press ENTER
   4. Select "meters" and press ENTER

1. 1. Select "formats" in the "setup – configuration" menu. Press ENTER
   2. Scroll down to degrees, and press ENTER
   3. Scroll to "DD.ddd’ and press ENTER.

1. Once these settings have been changed, the GPS is ready to collect data. However you may want to delete stored files (these eat up the 1Mb memory). Make sure you don’t need these files! Files to delete can include roving, base, data dictionary, or possibly others.

1. 1. To delete stored roving (R) files and base (B) files:

1. 1. Press the DATA button, the "file" sub-menu pops up.
   2. Press the OPTION button.
   3. Select "delete file(s)" and press ENTER
   4. Select the desired file to delete and press ENTER
   5. Steps 3 and 4 must be repeated for every R or B file.

1. 1. To delete stored "data dictionary files":

1. 1. Make sure that you have first deleted all the files under the DATA menu.
   2. In the SYS menu select "data dictionaries" and then select any additional data dictionary files except for the "tutorial" and "generic" files.
   3. Select the desired data dictionary file(s) to delete, and press OPTION.
   4. Select "delete" and press ENTER
   5. Repeat until data dictionary files are deleted.

Collecting Data:

• Multiple point, line, and polygon features can be stored within the same roving file. Every roving file will look something like this: R050121A. This weird code actually says a lot about the type of file and when it was collected. The "R" means it’s a roving file (vs. a base file, B). The "05" refers to the month (May). The "01" refers to the date (1^st day of May). The "21" refers to the hour (on a 24 hour system). The "A" means it was the first file collected in this certain hour on this certain date.
• When collecting data, take notice of several icons on the screen:

1. 1. Notice the small icon that looks like a battery. This is the battery meter! If the battery is all black the GPS is fully charged.
   2. If you use up too much memory, an icon looking like a spider (microchip) will appear above the battery icon. If this icon appears, I don’t recommend that you collect data. Chances are the features will not be recorded.
   3. Battery and memory levels can also be checked in the SYS – Status menu.
   4. Pay close attention to the number of satellites the GPS is receiving signals from! This is the number below the satellite icon. The more satellites the better! If this number goes below 4 or begins to flash, the GPS isn’t receiving a good signal. Data won’t be collected while the satellite icon is flashing!

• Battery and especially memory levels will be greatly influenced by the data collection interval (see above section). If a large amount of data is to be collected, I recommend that you keep the interval over 5 seconds.
• If the GPS is used as a base station, the memory will be used up in under an hour if set to record every second. This is a bad decision! Use a 5 or more second interval.
• Decide what you intend to do (feature size, time, and desired detail) before you begin collecting data. Make sure the configuration settings reflect what you are doing.
• Each separate file (not feature) must be recorded for at least ten minutes (if using differential post processing). The ten-minute span applies only to "carrier time" (the amount of time the unit receives a carrier signal), but not the actual amount of time you record features in a file. This doesn’t have to be a continuous, non-broken recording time (most of the time the carrier signal is difficult to keep a lock of for more than a few minutes, depending on satellite availability. Make sure you have at least ten minutes of carrier time (this is what I have been told by Gene Hoerauf), but I’ll bet the required carrier time is less than this. I didn’t decide to press my luck. This would be a good topic for a GPS study!

1. 1. Collecting point feature data:

1. 1. Press the DATA button.
   2. Select "create a new file" and press ENTER
   3. Select "latter" by pressing the right hand arrow button.
   4. Select "point" and press ENTER.
   5. "Comment" will automatically be selected. Press ENTER again.
   6. Select the appropriate comment (label) for the feature you are recording. When the data is converted into a spatial coverage (ArcInfo or ArcView) the "comment" text will be the only way to differentiate features. It is okay to have multiple features named the same thing, but they must be the same type of feature. Examples of my point feature comments: MAD for madrona, MDF for mature Douglas fir, SGATE for the south gate, etc.
   7. Press the CLOSE button (or select CLOSE and press ENTER) after a comment has been entered.
   8. Begin data collection by pressing the LOG button.
   9. I recommend that you record each point at least five times (beeps) if using a 5-second collection interval. If using a 1-second collection interval, I recommend collecting for twenty beeps. This is because the CORS differential signal is recorded every 5 seconds for hourly data files, and every 30 seconds for 24 hour files (see projlog or proclib: Pathfinder Office). Each recorded position of an individual feature is averaged together, so presumably, the more beeps the greater the precision. One beep for each feature would work, but the precision of the position would be minimal.
   10. After the desired number of positions have been logged, press the pause button (same as the LOG button).
   11. Press the CLOSE button, and select the type of feature you would like to record next. If done collecting data for that file, press the CLOSE button again to close the roving file.

1. 1. Collecting line feature data:

1. 1. Follow the steps for collecting point features, but in step 4 select "line".
   2. Let the GPS record one point of the line and begin walking. The slower you walk the greater the detail, but the more memory you will use. Changing the collection interval will also effect the detail.
   3. When done walking the line, press the pause button (same as LOG button).
   4. Press the CLOSE button, and select the type of feature you would like to record next. If done collecting data for that file, press the CLOSE button again to close the roving file.

1. 1. Collecting area (polygon) feature data:

1. 1. Follow the steps for collecting point features, but in step 4 select "area".
   2. Let the GPS record one point of the area and begin walking. The slower you walk the greater the detail, but the more memory you will use. Changing the collection interval will also effect the detail.
   3. Be sure not to walk past your starting point, otherwise your corrected shapefiles will have funny little tails on them. ArcView doesn’t like these tails!
   4. If you walk short of your starting point, the last point will be joined to the starting point by a straight line. This is the recommended method.

1. 1. When done walking the polygon, press the pause button (same as LOG button).
   2. Press the CLOSE button, and select the type of feature you would like to record next. If done collecting data for that file, press the CLOSE button again to close the roving file.

Viewing the Collected Features on the GPS Screen:

1. 1. If the roving file is open:

1. 1. Press the DATA button until the "map" sub-menu comes up. The polygon and line features will look weird since they haven’t been differentially corrected.

1. 1. If the roving file is closed:

1. 1. Press the DATA button until the "file" submenu comes up.
   2. Select "open selected file" and press the down arrow button to select "file: R______". Press ENTER.
   3. Select the desired roving file and press ENTER.
   4. Press the DATA button until the "map" sub-menu comes up. The polygon and line features will look weird since they haven’t been differentially corrected.

My Final Thoughts:

• Make sure the roving file has been closed before you turn the GPS off (hold down the black oval button).
• Be kind to the GPS and it will be kind to you. These units are very water resistant, but don’t let them fall into a stream or lake. Underwater data collection is out of the question.
• Dense vegetation, as well as close proximity to large buildings will impair satellite signals.
• Hold the GPS unit high (away from your body) and it will receive a cleaner signal.

GPS Data Conversion Using Pathfinder Office

Purpose: To convert raw GPS data into ESRI shapefiles.

Necessary Software\Equipment: Pathfinder Office, A Trimble GeoExplorerIII GPS (or a roving file stored on a disk), and a Trimble Serial Clip or Cradle.

Preconditions: The GPS unit has a valid roving file recorded in the memory, or the roving file on disk is of a valid format.

The Basics:

• Pathfinder Office is software produced by Trimble that downloads and uploads files from a GeoExplorer GPS.
• A "roving file" is the raw data that the GPS collects. A roving file will have a name similar to this: R050121A. This weird code actually says a lot about the type of file and when it was collected. The "R" means it’s a roving file (vs. a base file, B). The "05" refers to the month (May). The "01" refers to the date (1^st day of May). The "21" refers to the hour (on a 24 hour system). The "A" means it was the first file collected in this certain hour on this certain date.
• This proclib only deals with downloading data from the GPS unit.

Initial Startup:

1. Place the GPS into the GPS cradle or serial clip.
2. Start up Pathfinder Office: Start Menu – Programs – Pathfinder Office
3. Create a GPS project folder in c:\temp:

1. When you start Pathfinder Office, a little dialog box will pop up. You need to tell Pathfinder where you want to locate all the files that it will create/use.

1. 1. Click the "new" button
   2. Type an appropriate project name
   3. Click the "browse" button located to the right of the "project folder field".
   4. Scroll down to the c:\temp, and double click on the folder.
   5. Click the "OK" button in the "Project Folders" menu.
   6. Click "OK" in the "select project" menu
   7. You are now ready to download the GPS data (almost).

Downloading Data from the GPS: (IF YOUR ROVING FILES ARE ALREADY ON A DISK, SKIP TO THE "DIFFERENTIAL PROCESSING" SECTION).

1. From the "Utilities" drop down menu, select "Data Transfer".
2. If nothing pops up onto the screen, click the "data transfer" button on the bottom of the screen.
3. The data transfer menu will tell you what roving files area available from the GPS under the "available files" field. To download these files:

1. Make sure that the "destination directory" is set to c:\temp\base. If not:

1. 1. Click on the "destination directory" button.
   2. Browse to the c:\temp\base folder, and double click on it (the "base" folder icon will open)
   3. Click "OK".

1. Click on one (or more using the SHIFT key) of the roving files (example R050121A). Make sure that all the file(s) you want are selected.
2. Once the desired files are selected, click on the "transfer" button on the right of the menu. This can take a really long time, depending on the size of the roving files.
3. Once the data transfer is successful, the roving file(s) will be located in c:\temp\base.

Differential Processing:

• This section deals with differentially processing the uncorrected roving files with either a CORS station or a GPS unit set up as a base station.

1. From the "Utilities’ drop down menu, select "Differential Correction".
2. An error message will pop up, just click OK, and then click on the Differential Correction button at the bottom of the screen.
3. Tell the computer what roving files you want to correct:

1. Click the "browse" button in the roving files part of the menu (the top browse button).
2. Navigate to where the roving file(s) are located (c:\temp\base) and click "OPEN’.

1. You have several options at this point in terms of where to get the correction data:

1. From a GPS unit set up as a base station.

1. These base files are very similar to roving files in appearance, except they will have a B at the beginning (example B050121A). These can be downloaded from the GPS unit the same way as a roving file.

1. From a CORS base station.

1. 1. Files can be downloaded from the Internet (very easily), but often won’t work via the Internet if the roving files were collected more than 12 hours ago. However, this method needs to be attempted first. Even if you can’t get the correction data you need, the computer will let you know what the names of the correction files you need (briefly, so write these down fast!). You will need to know these file names if you use the FTP method. Look at 5) Here’s how to get CORS data via the Internet.
   2. If the roving files are too old to be had from the Internet, they can be downloaded from an FTP (file transfer protocol) site. This is a bit more complicated than the Internet method, but isn’t that bad. Before you use the FTP method, look at 5) Here’s how to get CORS data via the Internet, and then 6) Here’s how to get CORS data via FTP.

1. Here’s how to get CORS data via the Internet:

1. Click the "Internet Search" button.
2. Select the appropriate CORS station (CORS Whidbey Island, WA) is closest to WWU. If you want an alternate CORS station, click the "new" button, and select the closest station to where you collected the roving files. Ask Gene about this! Once you select the appropriate CORS station, click "OK".
3. Click "yes" you want to continue.
4. Here’s the important part if you are going to use the FTP method! In the little display, the needed correction file names will display. Write these down immediately. You should be writing down something like this: rpt1104v.00n.gz, rpt1104w.00n.gz, etc. Pay close attention to the 1104v part, as this is the day and hour information for the roving files. The following is a breakdown of this mysterious code.

1. 1. 1. rpt1 – This is the abbreviation of the CORS station you are using (Whidbey Island is "whd1").
      2. 104 – The last three numbers (104) are the day of the GPS data collection in terms of number of days after Jan. 1^st. Remember the last three numbers of all the correction files.
      3. V- this is how CORS stations keep track of hours of the day (Greenwich Mean Time, not Pacific standard!). The hours are from A to W (1 – 24). Make sure you write this letter down!
      4. 00n - the n indicates that it is a navigation file. I don’t know what the 00 means.
      5. Gz- gz is the abbreviation for g-zip, the format of file you are trying to download.

1. Here’s how to get CORS data via FTP:

1. Start up FTP: Start – Programs – WS_ftp – WS_FTP95 LE
2. Under the "host name/address" field type this: ftp.ngs.noaa.gov and click "OK"
3. FTP should connect with NOAA’s main FTP site.
4. The right site of the window represents NOAA’s files. The left side represents the files on your computer. On the NOAA side:
5. Double click on the "cors" folder.
6. Double click on the "rinex" folder.
7. This is where it gets a bit tricky. All these numbered folders are days of the year. The number represents the number of days after Jan. 1^st (i.e. 00003 means Jan. 3^rd). Refer back to 5) Here’s how to get CORS data via the Internet to see how to get the number file(s) you need to get from NOAA.
8. Double click on the appropriate numbered folder. As discussed in the "Here’s how to get CORS data via the Internet" section, you only need to know the last three numbers (114 will transfer to 00114). Your correction data might be stretched over two days, especially if you collected your roving file(s) in the early evening. Remember that CORS time is Greenwich Mean Time, not Pacific Standard.
9. Double click on the appropriate CORS station folder (whd1 is the CORS station at Whidbey Island).
10. If your roving files were collected recently, the FTP site should contain correction data in an hourly format (remember the 24 hour letter system, a-w). The hourly data will look something like whd1114v.00n, and each hour will have a few different .00_ endings: s, n, and o for example. If you want hourly data be sure to grab all the files (s, n, o, etc.) for that particular hour. The hourly data is more precise than the 24-hour data, which is usually listed at the top of the daily file menu. 24-hour files don’t have the a-w hour letters, so they look like: whd11140.00n,s,o, etc. Also the 24-hour files tend to be much larger than the hourly files. Typically, NOAA deletes the hourly files in a few days, but the 24-hour files remain all year. Also the 24-hour files are the easiest to deal with (, as you only need to worry about a few files for each day). Although convenient, there will be certain amount of precision loss when using 24-hour files, so use the hourly format whenever possible.

1. 1. 1. On the right side of the FTP screen, double click on the C:\temp\base folder. This is where the correction files will be transferred.
      2. On the right side, select (click on) all the correction files you want to transfer and then click the LEFT arrow button in the middle of the screen. It will take a few seconds, but the correction files will transfer to c:\temp\base.
      3. If you have transferred all the necessary files, you can close FTP, and go back to Pathfinder Office.

1. Back in Pathfinder Office, and the "differential correction" window, hit the "local search" button. This will search for CORS correction data in the specified folder c:\temp\base. If the correction data is somewhere else, hit the "browse" button, and locate the files yourself.
2. Hit the "search" button in the "local search for base files" window.
3. A window called "confirm selected base files" will pop up. If the CORS correction files correspond to the time the roving files were collected, the "coverage" will be 100%. If lower than 100% you need additional correction files, or else the roving file data won’t be processed in its entirety. If 100%, click OK.
4. If the "reference position" data (exact x-y-z position of the selected CORS station) is correct, press OK.
5. Back in the "differential correction" window, click the "OK" button in the top right corner.
6. It will take a while for the computer to think. It will then spit out a summary of the differential processing success or failure. As long as some features were processed Pathfinder Office will write a differentially processed version of the roving file to c:\temp. Use NT Explorer to make sure. The file icon is a little target symbol.

Converting the Corrected (or Uncorrected) Roving to an ESRI Shapefile or Coverage:

1. Back in Pathfinder Office, select "export" from the "utilities" drop down menu. The "export" window will pop up.
2. Select the appropriate corrected roving (blahblah.cor) file that you want exported. Hit the "browse" button if you don’t see it in the "selected files" field. Note: you can export uncorrected roving files (see step 4C).
3. Pay attention to the "output folder" location. It should be c:\temp\export.
4. Look at the "choose an export setup" section. Verify that this is the format, coordinate system, projection, etc. you want your data exported as. If not:

1. Hit the "change setup options" button.
2. Look at "coordinate system" tab, and make any necessary changes.
3. Under the "position filter" tab, you can designate if you want to export uncorrected roving files by checking the "uncorrected" box.
4. Once all the settings are in order, click the "OK" button.

1. Back in the "export" window, verify that all the settings are correct, and then press "OK".
2. A summary of the export success will pop up to tell you how the export session went.
3. Kazam!!! In c:\temp\export the exported ESRI shapefiles or coverages will be found, ready to be used by ArcView or ArcInfo.

Acquisition of 24k DRG Via-Internet

Necessary software: A java-enabled web browser.

Purpose: To acquire a digital raster graphic (USGS topographic map) from an Internet source (www.gisdatadepot.com).

Procedure:

1. Start Netscape Navigator: Start – Programs – Netscape Communicator – Netscape Navigator
2. Go to this web site: www.gisdatadepot.com
3. Click on the green arrow icon (free data).
4. Browse to the desired DLG you wish to use (24k, 100k, 250k, etc).
5. Follow the instructions provided on the screen.
6. Once the data has been successfully transferred (to C:\temp), you can add it (as an image theme) to ArcView.