Soil and Water Conservation Laboratory Standard Operating Procedure

Transcription

1 Soil and Water Conservation Laboratory Standard Operating Procedure Sherman 230, Soil and Water Conservation Laboratory, UH Mānoa Collecting GPS data with the Trimble handheld through ArcGIS & related programs Required Programs: ArcGIS GPS Analyst ArcPad GPScorrect Microsoft ActiveSync I. Create a GPS enabled geodatabase (gdb): Open ArcCatalog A. Create a new personal geodatabase In left panel, right click on the folder where you want to place the new gdb, select New, select Personal Geodatabase New gdb appears in right panel, enter desired name In left panel, find new gdb, right click, select Properties, select GPS Analyst tab Click box to enable for GPS Click Set Spatial Reference to specify the spatial reference for the gdb For Hawaii, consider NAD 1983 UTM Zone 4N Change X & Y precision and Z min values, can leave others as default, list below: MinX = MaxX = MinY = MaxY = Precision = 20 Z Min = Z Max = Precision = Set Geographic Transformation, use NAD_1983_to_WGS_1984_3 for Hawaii 1

2 B. Create new feature dataset In left panel, right click on new gdb, select New, select Feature Dataset Enter name for feature dataset (e.g., GPS_Data) Specify the coordinate system, can use same as gdb Accept default for all other parameters C. Create feature class in new feature dataset In left panel, right click on new feature dataset, select New, select Feature Class Enter desired name for feature class (e.g., Waypoints), repeat for Alias Select Point Feature Leave M & Z coordinate info as default Enter desired fields and their data types (e.g., Name, text; Avg_Est_Accuracy, Double; Worst_Est_Accuracy, Double) D. GPS enable Feature Class In left panel, right click on new gdb, select Properties, select GPS Analyst tab Click box next to new feature class (e.g., Waypoints) to be GPS enabled Click Apply (Optional, but required for validation) Click on Feature Class Properties button For the average estimated accuracy, select Avg_Est_Accuracy from drop down menu For the worst estimated accuracy, select Worst_Est_Accuracy from drop down menu Enter the desired accuracy required for validation (e.g., 1 m) Create and import other data and feature classes as desired 2

3 II. Create a map Open ArcMap Open empty map, save with desired name (helpful to make it same as gdb) Add feature classes, rasters, etc. to make the map look like you want Zoom into the area where GPS data will be collected On the toolbar, click GPS Analyst, select Start GPS Editing Add GPS enabled feature class (e.g., Waypoints) On the toolbar, click GPS Analyst, select Stop GPS Editing (save GPS edits if you have that option) Save map III. Export map to ArcPad Open desired map in ArcMap (if not already open) Zoom into area that you want the ArcPad map to include On the toolbar, click GPS Analyst, select Start GPS Editing On the toolbar, click Get Data for ArcPad AXF button Select feature classes to: Check out for disconnected editing in Arcpad Data based on defined extent (e.g., any GPS feature class, e.g., Waypoints) Export as Background Data (to Shapefile) Make read only (most everything else, e.g., road maps, soil units, etc.) Raster images are more difficult to export, avoid this if possible 3

4 Export only the current display extent Name the ArcPad map, its folder, and where to store it Select Create ready to deploy.cab file containing the ArcPad data and Create the ArcPad data on this computer now, then select Finish The pop up window may indicate that some layers were not processed, but if it s because the layer shares the same info as another layer (e.g., State Parks km was not processed because National Parks km was already processed), that is okay, continue The folder will transfer when Trimble handheld is connected to the computer (use Microsoft ActiveSync) IV. Collect GPS data with ArcPad on the Trimble handheld On Trimble, click Start, click ArcPad 8.0 Double click on desired map to open Toolbars: A. To make viewing easier, may need to: Change scale to Always show for some features Turn on/off labels Zoom & bookmark spots 4

5 B. Select GPS layer for editing On Main toolbar click Table of Contents button Find the row for your desired GPS layer and select it for editing by checking the box in the Pencil column Click OK If more than one GPS layer is selected as editable, make sure the one you want is highlighted (in orange) on the Start/Stop Editing button in the Edit toolbar C. Check these GPS properties in ArcPad: On Main toolbar, click GPS Position Window drop down list, select GPS Preferences GPS tab Capture tab Protocol = Trimble GPScorrect Port = COM3: TSIP Serial port Baud = 4800 Show GPS Activity in System Tray, Automatically Pan View, and Log boxes all checked check Enable Averaging box, Points = 10, Vertices = 5, Position Interval = 1, Distance Interval = 10 GPS Height tab Antenna Height = 1 **If not using antenna, Antenna Height = 0 Geoid Separation = 0 Use map units for height units checked, Units = Meter D. Check these GPS properties in GPScorrect: Select GPScorrect toolbar, click GPScorrect button In upper left drop down menu, select Setup Click Logging Settings button Log GPS to SSF = On Antenna Height = 1 m (= 0 if no antenna) Click Tools button Click GPS Settings button Antenna Height should correspond to ArcPad value In Type drop down menu, select Zephyr if using the antenna and GeoXH Internal if not Make sure set to 100% Productivity DOP Type = PDOP Max PDOP = 20.0 Min SNR =

6 Min Elevation = 5 Velocity Filter = Off Use GLONASS = Auto Click Tools button Accuracy value for display/logging = Horizontal, In the Field Click Real time Settings button Choice 1 = Use Uncorrected GPS Return to ArcPad by clicking the ArcPad icon/button on the upper right of the GPScorrect window E. Activate GPS and collect data If using the antenna, plug it in now Click GPS Active button Will hear chime if GPS activates, wait a minute or so for it to find and lock on satellites, moving to another spot if necessary. Can go to GPScorrect to get a good view of the available satellites by selecting the GPScorrect toolbar and clicking on the GPScorrect button Return to ArcPad by clicking the ArcPad icon/button on the upper right of the GPScorrect window Capture a GPS waypoint by selecting the Edit toolbar and clicking on the Capture Point using GPS button Enter desired name for the waypoint, wait for averaging to finish, click Okay Click Save button on Main toolbar When GPS is active, do not let the Trimble go into suspend mode because it may cause issues Make sure to de activate the GPS before closing the map To de activate GPS, click GPS Active button again Save map 6

7 V. Check edits back in to ArcGIS Connect Trimble handheld to computer, replace original Arcpad folder on computer with edited ArcPad folder from the Trimble In ArcMap, open the same map from which the data was checked out On the toolbar, click GPS Analyst, select Start GPS Editing Click Check in ArcPad AXF file and GPScorrect SSF to check in edits Select desired folder & map On the toolbar, click GPS Analyst, select Save Edits In left panel, right click on GPS Positions, select Properties, select Display tab Select from all GPS sessions box to see GPS symbology on map when in editing mode On the toolbar, click GPS Analyst, select Stop GPS Editing Save Map VI. Differential Correction of GPS points Open map in ArcMap On the toolbar, click GPS Analyst, select Start GPS Editing If small red squares are not visible on the waypoint locations, right click on GPS Positions in the left panel, select Properties, select Display tab, select from all GPS sessions box On GPS Analyst toolbar, click Differential Correction button Select GPS session you want to correct, remove any others 7

8 Follow prompts for Differential Correction. Consider these parameters: Standard Code Processing Only (may be able to do H Star, but I haven t tried this yet) Smart Automatic Rover Filtering Re correct Real Time Positions Update Base Provider list and select Base Provider with shortest distance and highest rating Use most recent GPS positions from all GPS sessions Filter by correction type Do not filter by position quality Manually edited geometries will be replaced with GPS geometries If selected Base Provider provides 100% coverage, continue with correction. If not, go back and try another Base Provider When complete, you should see that the points from the waypoints shapefile have moved to the center of the green (corrected) squares On the toolbar, click GPS Analyst, select Save Edits, then Stop GPS Editing Save map VII. Validate corrected GPS points Prior to validation of points, accuracy and validation requirements must be specified in the gdb properties, GPS Analyst tab, Feature Class Properties button Open map in ArcMap On the toolbar, click GPS Analyst, select Start GPS Editing On GPS Analyst toolbar, click GPS Feature Validation button Select Validate all features New window opens showing results Close validation window by clicking X button at top right of window On the toolbar, click GPS Analyst, select Save Edits if option is available, then select Stop GPS Editing Save map 8

9 Remember: Export only what you really need to ArcPad; big files or too many maps make it extremely slow. Any layers to be added to the map, especially if they will be exported to ArcPad, should be imported into the map s main gdb if at all possible. Before activating the GPS in ArcPad, the antenna height should be checked and changed if needed (internal vs. external Zephyr). Make sure to start GPS editing whenever you alter anything about the GPS linked features. Then make sure to save the edits. Troubleshooting for problems in ArcPad If you get a COMM Port error message when trying to activate GPS: De activate GPS, go to Table of Contents, un select the soil map unit feature class, click OK. Activate GPS again. If it works, then go back and select the soil map unit feature class to be shown again. If the above action doesn t work, try to get GPS to activate by un selecting other features in the Table of Contents. If you need an un selected feature and the GPS won t continue working when the feature is reselected, try adding it as a new layer if the feature is present in another map on the Trimble handheld. If the problematic feature is editable, try activating GPS while the feature is selected for editing. Lastly, you can open a new, empty map, activate GPS, add the necessary features as new layers and see if the GPS will continue to work. To help avoid this problem, make sure the soil map unit feature class you exported was imported into the main gdb for the map (and added to the map from that gdb). If you have problems with the attribute fields not showing up, etc., when exported to ArcPad, try to export the soil map unit feature class as editable. If the feature symbology is not displayed as it should be, it may be related to a join performed on the attribute table while in ArcMap. You will need to add it again as a new layer from another map on the Trimble if there is one that is not affected. You could try exporting the feature as editable, but otherwise you will need to make a new map if that symbology is needed. 9