Wetland Resource Attribution and Verification Tools

Table of Contents

System Requirements
Installing the Custom Attribution and Verification Tools Version 2.5.1
Using the Attribution Tools
Using the Verification Tools

Attachments

Attachement 1: Crosswalk of Verification and Quality Control Functions
Attachement 2: Software Modification Form
Attachement 3: Frequently Asked Questions
Attachement 4: Common Errors and Solutions using the Wetlands Verification Tool

Disclaimer

The use of trade, product, industry or firm names or products is for informative purposes only and does not constitute an endorsement by the U.S. Government or the Fish and Wildlife Service.

System Requirements

The customized Attribution and Verification Tools are extensions to Environmental Systems Research, Incorporated’s (ESRI) ArcMap desktop geographic information system (GIS) product. Therefore, any workstation you intend to run the tools on must be capable of running the ArcGIS suite including Arc Desktop and Arc Workstation. ESRI has published system requirements for ArcGIS at their web site: www.esri.com. The following minimum hardware and software requirements are necessary:

Hardware:

• CPU with a clock speed of 2 gigahertz or faster

• 1 gigabyte of physical RAM

• AGP video card with 32 megabytes of video memory

• 10/100-base-T network adapter

• SCSI or ATA100 IDE hard drive(s)

• 1024 x 768 resolution monitor

Notes: RAM made more impact on speed and functionality than CPU speed. ArcMap reliability was affected by the virtual memory configuration, especially the location of the virtual memory file.

GIS Software:

• ArcGIS Version 9.1 or 9.2

Operating System

• Microsoft Windows XP

Installing the Custom Attribution and Verification Tools (Version 2.5.1)

There are a couple of steps to follow for installing the Attribution and Verification Tools, version 2.5.1. By following these guidelines most installation problems can be resolved:

STEP 1. Review the System Requirements document included with this information to be certain you have the necessary hardware configuration and basic software to support these operations.

STEP 2. The Attribution and Verification Tools must reside in a directory on the same hard drive that the operating system resides. This is typically the c:\ drive. Create a new directory for the tools called c:\nwitools. Copy all the files: nwiAttrib.dll, nwiDelPart.dll, nwiFav.dll, nwiQAQC.dll and nwi.mdb into the newly created c:\nwitools directory. The files can be loaded from a CD or can be found at: http://capp.water.usgs.gov/FWS_web/index.htm.

NOTICE* If you copied the files from a CD, then Windows gave the files Read-Only attributes. This will cause problems unless the files have full, read-write attributes.

1) Open Windows Explorer and navigate to the file(s)

2) Right click the file(s) and click “Properties”

3) Uncheck the “Read-Only” box on the bottom of the window

You cannot move the .dll files and copy them once you have initially installed these files. Their location on disk is stored in the Windows registry. This is true for all .dll's, not just the NWI tools. Both Windows and ArcMap look in the registry for the locations of all .dll's. If you need to move the files, you must first unregister the .dll's with the regsvr32.exe program and the /u option. If you are unfamiliar with Windows .dll files, you should avoid moving the files. Until you can get help, it's best to accept your original installation location. Alternatively, please read the documentation on regsvr32.exe

STEP 3. Windows must know where the tools are stored so it can provide the path name to the ArcMap tools when they are loaded. You need to create an environment variable called NWIHOME. The case of the variable name is irrelevant, but by convention all environment variables are all uppercase characters. The variable's value is the directory where you copied the files. In this case the name would be c:\nwitools.

Create the environment variable using these steps (using Windows XP):

1) Right-click “My Computer” then click “Properties”

2) Select the “Advanced” tab

3) Click the “Environment Variables ...” button

4) In the TOP frame, click the “New...” button

5) Enter “NWIHOME” (no quotes) for the Variable field

6) Enter “c:\nwitools” (no quotes) for the Variable Value: field

7) Click OK

8) Click OK

9) Click OK

STEP 4. Create a new toolbar in ArcMap for the new tools:

1) Open ArcMap

2) Click “Tools”

3) Click “Customize...”

4) Select the “Toolbars” tab

5) Click the “ New...” button

6) The Toolbar name can be “NWI Tools”

7) If you always want the NWI Toolbar to be displayed, save the Toolbar in normal.mxt. (It is probably better to establish a NWI editing session and save the Toolbar in that document.)

8) A small 'floating' toolbar will appear somewhere on your screen. This can be 'docked' to the ArcMap window by clicking and dragging it to the desired location on the ArcMap window.

STEP 5. Once you have a toolbar, you must show ArcMap where on the disk the .dll files are located. Arc does the rest, including telling Windows.

1) With the “Customize” window still open (step 4) select the “Commands” tab.

2) Make sure the Save In document is the one you want to use

3) Click “Add from file...”

4) Navigate to the c:\nwitools directory and choose one of the .dll’s (for example: nwiAttrib.dll)

5) Repeat this step for the other three tools (.dll’s)

STEP 6. Once ArcMap knows the location of the .dll’s you now need to add three of the NWI Tools to the toolbar.

1) With the “Customize” window still open (step 4) select the “Commands” tab.

2) Select “NWI” from the “Categories” list. The tools should appear in the “Commands:” list.

3) Click and Drag each tool to the new tool bar you created, but NOT the delete part tool.

4) You may now symbolize the tools on the tool bar by right clicking each one independently. The current standard is to select ‘Image and Text’ then ‘Change Button Image’ to the following:

Attribute Tool =Favorites Tool =and Verification Tool =

STEP 7. Placing the “Delete Part” tool.

1) To place the Delete Part tool Select the “Toolbars” tab on the customize window.

2) Check the “Context Menus” from the Toolbars list. A floating “Context Menus” should appear on your screen.

3) Click the pull down menu on the “Context Menus” toolbar and select the “Sketch Menu” on the bottom of the list.

4) Select the “Commands” tab on the Customize window and Click and Drag the “Delete Part” tool to the “Sketch Menu” window and place it just below “Finish Part”.

Using the Attribution Tools (Version 2.5.1)

The Attribution Tools were designed as ‘resource mapping’ tools to help attribute mapped features that may depict wetlands, deepwater, riparian areas, uplands or other natural resource features. The Attribution Tool can be used as a reference for uncommon or rarely used codes or to assist those not familiar with the wetland alphanumeric mapping codes. It is anticipated that the Attribution Tool and menus incorporated within it, will be useful even to the most experienced NWI wetlands interpreter for coding and labeling upland and riparian areas, applying hydrogeomorphic modifiers or adding qualitative indicators. Many image analysts experienced in the use of the Cowardin wetland classification system and the NWI mapping codes may not find the Attribution Tool useful for routinely attributing wetland polygons. The Attribution and Favorites tools work with the standard NWI field ‘Attribute’, which is a text field with length of 20.

The Attribution Tool

The main Attribution Tool (Figure 1) contains the entire Cowardin hierarchal scheme for the classification of wetlands and deepwater habitats (Cowardin et al. 1979). Tabs compartmentalize the System, Subsystem, Class, and Subclass classifications (Wetland

Figure 1. The Attribution Tool Version 2.5.1. with ‘Modifiers’ file selected.

Systems tab) from the water regime and special modifying terms (Modifiers tab). The complete riparian classification hierarchy is accessed through a third tab. Hydrogeomorphic and upland classifications schemes are completed but not yet accessible in Version 2.5.1.

The alphanumeric codes appear in the “Classification (CCode)” text box each time a classification is selected from the hierarchy tree for wetlands. Water regime modifiers or special modifiers appear in the “Modifiers (MCode)” text box. The “Get CCode” and “Get MCode” populate the “Working Attribute(s)” text box with the complete attribute. The “/” button allows split classes to be entered (Figure 2). Any classification code can also be directly typed in the “Working Attribute(s)” text box. The “Update Selected Polygon(s)” button will apply the attribute from the “Working Attribute(s)” text box to any polygons that are selected in the ArcMap window. The “Add to Favorites” button ‘adds’ the attribute code shown in the “Working Attribute(s)” text box to a user’s list of frequently used codes. The codes are then available using the Favorites Tool (see The Wetlands Favorites Tool, below).

Figure 2. Example of a split class attribute with a modifier.

The Attribution Tool is not limited to alphanumeric code attribution. Attributes for use on specialized or custom maps do not need to be Cowardin alphanumeric codes. For example, geographic names or place names may be entered by typing the name into the “Working Attributes” text box and ‘updating’ the selected polygon(s). WARNING: This deletes the wetlands attribute and replaces it with the custom ‘name’ entered. This should only be done on a copy of the data for project specific cartographic representation.

The Wetlands Favorites Tool

The Favorites tool (Figure 3) was developed as a shortcut for efficiently and quickly updating wetlands with commonly occurring attributes. Attribute codes can be entered into the Favorites Tool using the Attribution Tool window, or using the “Favorites Manager”.

Figure 3. Example of Wetlands Favorites Tool with drop-down box open.

To add a ‘favorite’ attribute from the Attribution Tool, select the “Add to Favorites” button on the Attribution Tool after you have the desired attribute in the “Working Attribute(s)” text box. On the Wetlands Favorites tool click the “Refresh Favorites List” button. This will add the attribute to the pull-down list and the “Favorites Manager” list.

To add a ‘favorite’ attribute using the “Favorites Manager” click the “Favorites Manager” buttonon the Wetlands Favorites tool. The “Favorites Manager” window (Figure 4) allows a new ‘favorite’ attribute to be manually typed or cut-and-pasted into the top text box. After the attribute is entered in the text box, click “Add” to ‘add’ it to the list. The “Delete” button allows attributes to be removed from the list. When the desired list is finished, click the “Save” button to update your ‘favorites’ drop-down list. Click “Done” when finished.

Figure 4. Example of the Favorites Manger Window

Attribution codes entered into the Favorites Tool can be selected and applied to a single map feature or multiple features that have been selected in the ArcMap edit session by clicking the green arrowon the Wetlands Favorites Tool. Any number of attribute codes can be entered into the Favorites Tool depending on the needs of the image analyst. This list of ‘favorites’ is associated with a specific user and is available when that analyst logs into the computer uses ArcMap.

Using the Verification Tools (Version 2.5.1)

The Verification Tools Version 2.5.1, have been constructed to automate (to the extent possible) the quality control functions necessary to ensure the geodatabase is accurate¹. This suite of functions has been designed to address geopositional errors, digital anomalies, and some logic checks that make use of the power of the geographic information system.

Some functions the verification tools perform will flag potential problems but provide the image analyst the option of editing or ignoring the feature. This is to accommodate the image analyst’s ability to ultimately determine the best ecological portrayal of the data. For example, a small lake that is only 18 acres has been identified during the data verification process as a potential problem based on its size (18 acres) and classification (lacustrine). The analyst has information that the lake depth exceeds 90 feet and determines that lacustrine is the best ecological descriptor for this feature.

The verification tools allow the user to easily find attribute problems with the NWI wetlands polygons. There are two types of procedures involved. The first procedure is a non-interactive, intensive process that checks all the NWI attribute codes, repairs some of them and flags others for subsequent checks. The second type of procedure is an interactive process where the analyst uses the interactive mapping capabilities of ArcMap to visually identify specific topological and attribute features that may need adjustment. The Verification tools work with the standard NWI field ‘Attribute’, which is a text field with length of 20.

The tool incorporates the following:

• Allows the image analyst to perform a series of verification tests and optionally visualize the results of those tests through the use of ‘graphic elements’.

• Results of the tests are stored and managed by the Tool in a special field added to the layer’s attribute table.

• Provides the image analyst with a count of the number of errors found by a particular test.

• A “progress bar” provides the image analyst with an estimate of the processing time remaining until completion of a verification test.

• Provides a function that runs the most critical tests and produces either a ‘pass’ or ‘fail’ assessment of the QA/QC procedure.

Note: The Verification tool has been updated to Version 2.5.1. On the surface the tool and user interface has not changed. The verification program has been modified to improve speed and to better process large geodatabases. In particular, Version 2.5.1 significantly increases the speed of finding invalid wetlands attributes. Additionally, Version 2.5.1 better supports editing large geodatabases by periodically saving the pending edits stored in the ArcMap edit cache.

Description and Organization of the Tool

The Verification Tool is organized as a table (Figure 5). The rows of the table correspond to particular verification test, while the columns of the table refer to properties of a particular verification test.

Figure 5. Wetlands Verification Tool

Graphic Element Legend
The first column is a series of colored boxes linked by a vertical line to a checkbox titled “Draw Graphic Elements”. When a particular test is run the user has the option of adding graphic elements to the map to indicate wetlands that fail a particular test. A graphic element is a visual flag that assists the image analysts in locating wetlands with problems. Graphic elements are removed using tools on the “Draw” toolbar. They are visual pointers and problems in the underlying wetlands data are fixed using ArcMap “Edit” tools and/or the Attribution Tools. The color of the box corresponds with the color of the added graphic elements. Unchecking the “Draw Graphic Elements” checkbox omits the graphic elements if the image analyst does not wish to add them to the map.

Verification Tests
The second column labeled “Verification Tests” organizes both checkboxes and descriptions of each verification test. The verification tests are grouped by function and by color. The orange group includes tests for verifying wetland attributes. The green group includes tests for verifying the size of wetlands, specifically very small wetlands that may be slivers, and those with PUB or L1UB attributes, that are unusual in size. The blue group includes tests for topological problems, which should not exist in a properly organized geodatabase. Each of the groups is graphically and functionally linked to a button labeled “Find”. The procedure for running a verification test is to check off a particular test using its checkbox and then click the “Find” button to start the procedure.

QA/QC Codes
The third column, labeled “Codes” is an alternative identification tool designed into the verification process to identify ‘failed’ wetlands. Only those experienced with ArcMap attribute tables and selection tools should use this technique! The column labeled “Codes”, is a legend of the error codes associated with a particular test. As previously described, the verification tools record the results of the verification procedures using a special field added to they layer’s attribute table. The field is a 9-digit field named QAQC_CODE and each of the nine positions corresponds to each of the nine verification tests. If a particular test is run the results of that test are stored in the corresponding digit using the codes in the third column. For example, if the first test is run for finding wetlands with invalid codes, the character “C” is stored in the first digit of the QAQC_CODE for those wetlands that fail the test. Those wetlands which “pass” the test have valid codes and are given a value of “N” in the first digit which is a mnemonic for “No error”. A more complete explanation of the code is provided by pressing the button labeled “?” at the bottom of the list of codes (Figure 6.).

Figure 6. QA/QC Legend shown

Number of Problem Wetlands Found
The fourth column, labeled “# Found”, indicates to the image analyst the number of wetlands that failed a particular test. Ideally, the image analyst would run a particular test and the results would be zero.

Pass/Fail Check
At the bottom of the “# Found” column is a button labeled “Pass/Fail”. The “Pass/Fail” button automates the checking of the most critical verification tests. The most critical verification tests are “Unattributed or Null Attributed Wetlands,” “Adjacent Wetlands with the Same Attribute,” “Wetlands less than 0.01 Acres,” “Improper Island Polygons,” and “Overlapping Polygons.” If any of the tests indicate that any wetlands in the layer have any or all of these errors, the procedure is evaluated as having ‘failed’ the QA/QC procedures and the image analyst is notified with the message window shown in Figure 7.

Figure 7. Pass/Fail Results window

The last two areas of the Verification Tool are informational. The gray horizontal band below the “Pass/Fail” “Find”, and “?” buttons is a progress bar. The bar fills with a dark blue color to indicate the progress of a particular verification test. The white horizontal band at the bottom of the Verification Tool is a message box, which provides textual feedback to the analyst, describing the various tasks performed as part of the verification tests. The message box also displays various error messages. The message box holds 1000 characters and can be scrolled using the up/down arrows on the right side of the box and cleared using the ‘X’ button on the right side of the box.

Using the Graphic Elements
When the “Draw Graphic Elements” checkbox is checked all verification tests add a graphic element to the map indicating wetlands that fail the test. The graphic element is a visual flag that assists the image analysts in locating wetlands with problems. The graphic element is drawn in a hatched fill pattern in the color indicated by colored box in the first column. For example, wetlands polygons that overlap are indicated by an orange-hatched graphic element labeled “<OVERLAP>” drawn on top of the wetland (Figure 8.)

Figure 8. Overlapping wetlands

Graphic elements are used instead of either adding new features to the layer or creating a new feature class populated with the problem wetlands, because of the potential problem of inadvertently modified the copied features and not the original. Graphic elements are copies of the wetlands but since they require completely different tools to edit them, there is no chance that an image analyst would inadvertently modify any feature except the original.

Using the QAQC Code field
Only those experienced with ArcMap attribute tables and selection tools should use this technique! The previously described QAQC field, ‘QAQC_CODE”, can be used by any of the ArcMap attribution selection tools. Moreover, wetlands can be symbolized using the values in the QAQC_CODE field. Since each of the codes is unique simple queries can be used to select those polygons with specific errors. For example “QAQC_CODE” Like “*A*” could be used in the ‘Select by Attributes’ window to find all wetlands that failed the “Adjacent with Same Attribute” verification test.

Description of the Verification Tests

A brief description of each of the verification functions is provided below. Additional quality assurance issues not readily apparent on the verification tools may be handled by the geodatabase architecture itself. Refer to the crosswalk of NWI QC AML’s to Geodatabase Verification (Attachment 1).

Find Wetlands with Invalid Codes but Not Null

The first process this test conducts is to convert the old mapping code of “OW” to the known Cowardin type of “UB”. It also converts modifying terms that are uppercase to lower case, which is the current accepted convention (Many of the NWI wetlands quads tested had both of the described conditions). The second process this test conducts is to identify invalid codes. This process runs an exhaustive error checking procedure that checks every attribute for valid Cowardin System alphanumerics (codes), Subsystem codes, Class and Subclass codes, water regimes modifiers, and special modifiers. An additional check compares any of the illegal Cowardin attribute codes against a list of known map codes from existing digital files (6,400 possibilities). The polygons found with invalid codes are identified in the attribute table QAQC_CODE field with a “C” and on screen with a pink graphic drawing.

Find Unattributed and Null Attributed Wetlands

This test finds polygons that have a blank attribute field or contain “<Null>” in the attribute field. The polygons found with unattributed or Null codes are identified in the attribute table QAQC_CODE field with a “U” and on screen with a gray graphic drawing.

Find Adjacent Wetlands with the Same Attribute

This test searches for polygons that share a common border, but have the same value for the NWI attribute. This condition indicates that something is wrong with the attribute or the delineation since there should only be a single polygon. The polygons found that are adjacent with the same attribute are identified in the attribute table QAQC_CODE field with an “A” and on screen with a red graphic drawing.

Find attributes with > 1 Lowercase Modifier

This test searches for those polygons that have been given more than one lower case modifier. Although it is legitimate to have wetland features with more than one lower case modifier, these are usually rare. Identifying these attribute codes can help find miss-coded errors or force re-evaluation of labeling conventions. The polygons found that have more than 1 lowercase modifier are identified in the attribute table QAQC_CODE field with an “M” and on screen with a light-blue graphic drawing.

Find Wetlands < 0.01 Acres

This test searches for polygons that are on the cusp of being slivers, digital artifacts or very small polygonal features. Experience has shown that polygons smaller than this size (about 55 square meters) are slivers indicating a spatial processing problem. The polygons found that are smaller than 0.01 acres are identified in the attribute table QAQC_CODE field with an “S” and on screen with a dark-blue graphic drawing.

Find PUB Wetlands > 20 Acres

This test finds palustrine unconsolidated bottom polygons larger than 20 acres. By convention these size cutoffs determine system classification breaks in the absence of other information. The image analyst is given the discretion to make these classification changes or not. The PUB polygons found that are larger than 20 acres are identified in the attribute table QAQC_CODE field with a “P” and on screen with a green graphic drawing.

Find L1UB Wetlands < 20 Acres

This test finds lacustrine limnetic unconsolidated bottom polygons smaller than 20 acres. By convention these size cutoffs determine system classification breaks in the absence of other information. The image analyst is given the discretion to make these classification changes or not. The L1UB polygons found that are smaller than 20 acres are identified in the attribute table QAQC_CODE field with an “L” and on screen with a brown graphic drawing.

Find Improper Island Polygons

This test finds “improper island” polygons. An “improper island” polygon is a polygon that is nested completely inside another larger polygon, but the larger polygon does not have a “hole” corresponding to the nested polygon. When this problem is encountered, the larger polygon should be “repaired” by clipping a hole in it with the smaller island polygon with the Editor toolbar’s Clip menu command. The island polygons found are identified in the attribute table QAQC_CODE field with an “I” and on screen with a yellow graphic drawing.

Find Overlapping Polygons Function

This test is a more general case of the “improper island” polygon problem. It finds any polygons that overlap, which is an error in the geodatabase. The overlapping polygons found are identified in the attribute table QAQC_CODE field with an “O” and on screen with an orange graphic drawing.

Attachment 1: Crosswalk: AML Coverages QA/QC Checks and Geodatabase Verification

Currently the NWIC relies on digital QA/QC procedures that are written in ESRI’s Arc Macro Language (AML). AML is a scripting language for the Arc Workstation shell and is designed to manipulate and analyze geographic data stored in the ESRI geo-relational data model called ‘coverages’. Coverages are a file-based method for storing geographic data. The geometry of geographic features is stored in proprietary tables, while the geographic attributes are stored in the INFO database file manager. Although useful, the coverage data model was designed nearly 20 years ago and was optimized for the slower, storage limited computers of that era.

Today, there are tremendous advantages in using newer technologies to store and analyze geographic data using client-server, relational data base management systems (RDBMS). The most significant advantages are speed, multi-user, multi-platform, and remote access to geographic data. ArcGIS takes full advantage of the client-server, RDBMS mechanism by storing geographic data in RDBMS tables. ESRI calls this geographic data model a ‘geodatabase.” A Geodatabase is a sophisticated and efficient mechanism for storing geographic data. Geodatabases can store tabular or attribute data, feature classes such as wetlands or roads, collections of features called features datasets, and additional functionality such as attribute rules and domains, feature and attribute relationships, and geometric networks.

Many of the geopositional data checks that were written into AML queries of the NWIC QA/QC procedures are now inherent in the creation of a geodatabase using the ArcGIS tools. Many traditional georelational items found in coverages are now either not necessary or not possible in the creation of a geodatabase. For example, a geodatabase cannot be created without first defining the map projection parameters. The geodatabase verification process also takes advantage of modern desktop PC workstations for enhanced display and visualization and customized tool development. The highly interactive nature of a menu-driven desktop GIS software allows users to check the wetland classification accuracy along with cartographic precision.

A crosswalk contrasting the differences between the AML Coverages QA/QC checks and Geodatabase Verification Tools is provided to illustrate the functionality of each process and clarify how each quality check is addressed.

Obsolete Checks

(AML-Coverage specific checks that are not necessary in a Geodatabase)

Topological Checks

Attribution Checks

Enhanced Data Checks

Attachment 2: Software Modification Forms

Resource Mapping Software Modification Form

To be filled out by image analyst and sent to:

Thomas E. Dahl
U.S. Fish and Wildlife Service
Division of Habitat and Resource Conservation
555 Lester Avenue
Onalaska, Wisconsin 54650
FAX: 608-783-8450

View a PDF of the Resource Mapping Software Modification Form

Response Form

To be filled out by Tom Dahl and/or USGS staff and will be returned to image analyst along with the Resource Mapping Software Modification Form

Attachment 3: Frequently Asked Questions

Custom Attribution and Verification Tools for ArcMAP

Q. 1. I’m an experienced wetland interpreter and I don’t find the attribution tool useful for labeling NWI wetlands. Why is it here?

Answer: This is not a problem. The attribution tool can be used as a reference tool for uncommon or rarely used codes or to assist those not familiar with the wetland alphanumeric codes. It is anticipated that the attribution tool and menus will be more useful to experienced NWI personnel in the application of upland and riparian mapping codes, hydrogeomorphic modifiers or qualitative indicators.

Q. 2. What other functions are contained in the attribution tool operations?

Answer: The attribution and verification tools are being used by NWI specifically for wetlands mapping, but they were originally designed as ‘resource mapping’ tools. The attribution tool was designed so that additional lists could be added and used to attribute map features. Currently the attribution tool contains lists for hydrogeomorphic modifiers, uplands and the riparian classification hierarchy.

Q. 3. Why don’t the tools limit attribution to the list of legal NWI mapping codes?

Answer: There are several reasons. One involves Regional conventions that have developed over the years. Some Regions use map codes that are not used in other Regions. The attribution tool references the Cowardin classification system and allows any combinations to be created that are in the classification hierarchy. The Verification Tool, however, checks attributes against both the Cowardian classification system and against a list of known attributes and helps the user identify attribution problems. The tool also allows the ability to incorporate new codes, geographic specific codes, place names and other identifiers that may be used on custom maps.

Q. 4. Will the verification tool work for shapefiles and coverages?

Answer: No. The customized attribution and verification tools were designed to work specifically with geodatabases. They have not been developed or tested for use with shapefiles or coverages. Further, the Verification Tools ignore layers in ArcMap that are not stored in geodatabases.

Q. 5. Will this verification tool replace the current NWI QC routine (AMLs)?

Answer: Yes. Every function currently performed by Arc Macro Language (AML) in a Unix environment has been carefully accounted for in the new process. A crosswalk between the AML functions and the new geodatabase functions has been prepared to illustrate this transition.

Q. 6. What about topology?

Answer: There has been a great deal of confusion circulating in e-mails regarding topology and verification routines. The statement “We need topology to conduct our quality control.” is mis-informed, at best. The situation is that the NWIC QA/QC routines are confined to coverages. They are written in Arc Macro Language (AML), which is specific to the Arc Workstation environment. Nothing in a geodatabase can be accessed with these old QA/QC routines. Rest assured that geodatabases do support topological relationships. The data access is so much more efficient in the geodatabase model that topology is calculated “as needed” instead of “if needed” For those really interested in this subject there is additional information at www.esri.com/news/arcuser/0701/migrating.html.

Q. 7. What kind of testing has been done on the verification tool?

Answer: St. Mary’s University has used an interim version of the tools extensively for QA/QC processing of over 116 updated NWI quadrangles in Michigan. Further operational testing has been done for quads in IL, SD, and a random sample of 100 quads in the U.S.

Q. 8. What are the advantages of a geodatabase over coverage?

Answer: Some of the advantages of the geodatabase include:

· All geographic data are centrally stored and managed in one database

· Data entry and editing is more efficient.

· Geodatabases can accommodate very large sets of features without tiles or spatial partitions.

· ArcSDE geodatabases allow multiple users access and editing capability.

· Geodatabase annotation can be linked to the feature it describes.

· Instead of generic points, lines and areas users work with objects such as roads, lakes and rivers.

· Geodatabases can be created, accessed and managed through the standard menus and tools in ArcCatalog and ArcMap.

· The geodatabase is the direction technology is headed.

Q. 9. I’ve got a great idea that should be built into verification. Whom do I contact?

Answer: There is a ‘software modification’ form that can be used to document problems or make new suggestions. The form is easy to use and available to any user.

Q. 10. Will there be later versions of these tools?

Answer: Probably. That is why this version is numbered 2.0. Newer versions should take advantage of technological advances and new ideas.

which affect these tools.

Q. 11. I am not able to get the verification tools to work. What should I do?

Answer: Re-read the hardware/software System Requirements paper and the Installation Instructions for Custom Attribution and Verification Tools to be sure all the software has been installed correctly. Also refer to the Arc Users Manuals for ArcGIS Version 9.1 or 9.2 as appropriate.

Attachment 4: Common Errors and Solutions using the Wetlands Verification Tool

Error 91:

This error occurs when running the verification tools on a data set that has polygons with no Shape_Length or Shape_Area.

Cause:

While editing polygon geodatabases in ArcGIS some edit functions (clip, merge, dissolve, delete, etc.) periodically leave ‘ghost’ polygons. These ‘ghost’ polygons have an attribute, but do not have any length or area.

Solution 1:

1. Start Editing
2. Open the attribute table for geodatabase that has the problem.
3. Right click either the Shape_Length or Shape_Area field header.
4. Select ‘Sort Ascending’
5. Select all records that have ‘0’ for Shape_Length or Shape_Area, and delete them.
6. Save edits.
7. Stop editing
8. Run Verification Tool.

Solution 2:

1. Use the Repair Geometry tool in ArcToolbox

Note:
After any edit session is conducted, it is good practice to search the table for any ‘ghost’ polygons and delete them. This can be done using one of the Solution proceedures outlined above.

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