For our next blog topic, I’d like to discuss how a quality assurance (QA) plan can be used to ensure the production of quality GIS data. A QA plan is a document, usually created by a project manager, which identifies quality related objectives, standards and procedures for your dataset. These guidelines are used to maintain consistent quality control (QC) processes throughout the duration of a project and helps determine the success (or failure) of a project, and whether the deliverables meet customer expectations. In essence a QA plan is designed to ensure everyone involved in the project is on the same page about what quality means for your data and how you are going to measure and ensure compliance throughout the project life cycle.
The establishment of a QA plan has many benefits including less data rework because quality requirements have been identified ahead of time and are being measured and monitored throughout the project. Additionally, project teams often experience greater productivity since a QA plan drives the examination of the production processes for efficiency and effectiveness. For project managers, the QA plan supports quality policy guidelines that your organization may have already established for your projects. For customers, satisfaction is increased because deliverables of the project will meet or exceed their expectations as a result of taking the time to measure and meet quality standards.
To get the most out of editing in ArcGIS 10, use the
Layer Properties dialog box to (1) prepare symbology, (2) simplify attribute
fields, and (3) set a display expression. Doing these things for each layer you
plan to edit can help make your data compilation tasks easier and
straightforward. This post walks you through setting up a parcels land-use
layer so you can create and edit features in it.
Preparing the layer’s symbology
The Layer Properties > Symbology tab allows you to set the symbols
used to draw the layer. Since feature templates are based on the symbols used
in the map, be sure to symbolize your layers appropriately before you start
editing for the first time on a map since ArcMap creates feature templates for
you then, or anytime you create feature templates yourself. If you change the renderer
type after you create feature templates, you will end up with templates that do
not reflect the features you want to create.
When creating features, you should use either the Single Symbol or
Unique Values renderer. If you are symbolizing with unique values, make the
labels for your symbols meaningful, as the symbol labels become the names for
the feature templates. For example, the parcels layer has symbol category
labels taken from the raw attributes of AGR, COM, IND, RES, and UNK, which are
shortened versions of various types of land-uses. Expanding the text of the
symbol labels to Agricultural, Commercial, Industrial, Residential, and Unknown
will reduce the cleanup needed on your feature templates after they are created
and help other editors understand which features they are creating. The symbol
labels are also used in the entries in the table of contents and the map layout
legend, so there are additional reasons to do this. These graphics show the
Layer Properties > Symbology tab and the resulting feature templates in the
Create Features window.
When there is a problem with the symbol for a feature template, the
Template Properties dialog box displays an exclamation point icon in the
preview area. The template is also shown in the Create Features window as a
silver layer icon, rather than the symbol that will be assigned to the new
feature. This often happens when the symbology was changed dramatically after
the feature template was created, such as switching renderers or symbol
categories. If this occurs, look at the feature template’s default attributes
to ensure they match the current symbology or symbol category. You can also
simply delete the template and re-create it to synchronize the symbols.
When you look at your parcels layer in the Attributes
window, by default, all the fields are displayed in their original order and
with their names as they appear in the data source. The field names are hard to
read and understand since they use capital letters and underscores because
spaces are not possible in the actual field names. Fields that you cannot even
edit are displayed, which makes it harder to find the fields you want. This is
a lot of junk content to wade through when you want to edit these attributes! This
layer could benefit from some work on the Layer Properties > Fields tab.
The Fields tab is the central place for you to set up the
display properties of fields. Spending time organizing fields makes your
editing and overall ArcGIS experience more productive because the settings are
used throughout ArcMap, including in the attributes table, the Attributes
window, and the Identify window. In addition, they are maintained when you
share layers with others through layer files, layer packages, map packages, and
The left side of the Fields tab contains a list of all
the fields in the feature class or table, including any fields that have been
joined to it. If you have a long list of fields but only plan to edit the
attribute values for a few fields, hide the ones you do not need to by
unchecking them in the list. For the parcels layer, you might be only
interested in seeing information about the land-uses and the IDs, so you can turn
off nearly everything else. To save even more space, hide system fields that
ArcGIS does not allow you to edit anyway, such as the Object ID, Shape, Shape_Length,
and Shape_Area. This does not delete the fields; it simply turns them off to
make it easier to access the fields you want. Many dialog boxes have option
buttons that allow you to view all fields in a layer if you need to see them
The order of the fields list is the default order in
which they are displayed throughout ArcMap. You can change the order to promote
to the top of the list the fields you use most often. To reorder a field, click
it in the list and drag it to the position you want, or click the arrow buttons
to move it up or down the list. You can also select multiple fields and reorder
them at the same time. With the parcels layer, move up the IDs and land-use
code fields since you plan to edit them.
When you click a field in the list on the left, the individual field’s properties are displayed on the right side of the tab (the
right side will be blank when you have multiple fields selected). You can change
the properties that are shown in the Appearance section, which specify how the
contents of the field are displayed in ArcMap, but not the system information
under Field Details. When you click a row on the right side, an explanation of
the property is provided in the box at the bottom of the tab.
In the Appearance section, you should give your fields
aliases to specify an alternate field name that is descriptive and user-friendly.
Field aliases do not have to adhere to geodatabase naming conventions, so
aliases can have spaces between words or be as long as necessary. For example, for
the field, “LAND_USE,” set the field alias as, “Type of land-use.” The alias is
a lot simpler to read and understand than the source field name.
You can also set a field to be read-only, which means you
can view but cannot edit that field, regardless of the file or database
permissions. This is useful when you need to see the value of a field for
context, but do not want to inadvertently update its value. If you want to
distinguish certain fields-for example, to make them easier to see when editing
in the Attributes window-set the Highlight property to Yes. This will add
background shading so those fields will stand out from the others.
After a little cleanup, the list is a lot easier to
manage and edit. Only the most useful fields are shown, with clearer alias
names and a more appropriate order.
Two of the most popular requests on the ArcGIS Ideas site, where you can submit and
vote for ArcGIS software enhancements, are the ability to rename fields and
reorder them after they have been created. Although this functionality may not
be available in the underlying database, you can get the same result by
authoring your map and setting the field properties.
You should follow these guidelines when working with
stand-alone tables, since the field properties are used with tables, too. If
you create a relationship class to relate a table of landowner information to
the parcel layer, you can navigate through the related records to edit the
landowner table in the Attributes window. If you turn off unwanted fields, reorder
fields, and set other properties in the landowner table, it will be easier to find
and edit the table’s values, too.
Setting the display expression
The display expression is new with ArcGIS 10 and is found
on the Layer Properties > Display tab. Setting the display expression
ensures that the most useful information is displayed when representing a
feature in the Attributes window, the Identify window, in HTML Pop-ups, and
other places across ArcGIS. The display expression can simply be the contents of
a field by itself, which is similar to the primary display field from previous
releases. However, the display expression is more powerful because you can
customize the text. This allows you to enter your own text or combine the
contents of multiple fields. For example, you could write an expression that
would include the text, “Land-use type:” before the field value. This would be
entered on the Display Expression dialog box as, “Land-use type: ” + [Land-use
When editing, the display expression makes it easier to
navigate the Attributes window tree. Stand-alone tables have a display
expression property, so setting it on the table can help when viewing related
records, too. The display expression is also shown in the Edit tool selection
chip, which is a small pop-up that appears on-screen to help you select the correct feature when you click multiple overlapping features with the Edit
tool. For example, you are trying to select a road that overlaps a parcel
polygon. If you click the road, the selection chip appears, allowing you to
choose whether to you want to select the road line or the parcel polygon.
Content provided by Rhonda (Editing Team)
In our first blog topic, I’d like to discuss how ArcGIS Data Reviewer, a quality control (QC) tool for your GIS data, supports standardized QC. Quality control emphasizes validating the output according to defined quality assurance processes in order to uncover parts that do not adhere to the defined criteria. Many of the lessons I learned as a software tester have correlations to performing data validation. I’d like to share a few of these with you while talking about how Data Reviewer can be used throughout the quality control life cycle.
It’s a good idea to spend a little time preparing your map for editing. You’ll be a lot more productive and save clicks if you set up your map and data before you really get in and make edits. This post is part of a series on the subject.
Choosing where to store your data
ArcGIS allows you to create and edit several kinds of data. You can edit feature data stored in geodatabases and shapefiles, as well as various tabular formats. When gathering your data in preparation for a geographic information system (GIS) project, make sure all the data you want to edit is stored in the same workspace, which is a single geodatabase or a folder of shapefiles, since you can only edit one workspace at a time. If you are still using shapefiles, consider migrating to a geodatabase, such as a file geodatabase, which provides more functionality and storage capacity with as much speed and simplicity as shapefiles. You can use the geoprocessing tools for importing and exporting data, as well as often simply copying and pasting feature classes in the Catalog tree, to get data into a geodatabase.
With the Catalog window now embedded in ArcMap, you can perform data management tasks and access your data without having to open the separate ArcCatalog application. This is useful in itself, but a few additional settings can make your use of the Catalog window even more productive. For example, the directory where you save a map document is tagged as the Home location and is always promoted to the top of the Catalog window when that map is open. Therefore, if you put the geodatabase in the same folder as the map document you are working on, you can quickly find your data in the Home location without having to navigate through the whole folder tree. Doing this also keeps your GIS project better organized since all the data, maps, and other supporting materials are in the same place. In addition, you can set your geodatabase as the map’s default geodatabase (right-click it in the Catalog window and click Make Default Geodatabase) so any outputs will be saved in that location automatically.
Choosing the projection for your data
As you compile your data, you need to consider the projections. First, you should make sure the feature classes that you will be editing all have the same coordinate system. In addition, if you have data in a geographic coordinate system, you may want to change to an appropriate local projection. This will improve accuracy when editing and make it easier to enter lengths and other measurements since values are specified in the map units of the coordinate system by default. For example, if your map uses the geographic coordinate system of WGS 1984, when you are editing, ArcMap interprets any entered values as decimal degrees because those are the map units for that coordinate system. So when you type 100 for the length of a segment, as shown below, ArcMap interprets that as 100 degrees and will likely present you with a series of error messages. On the other hand, with a projected coordinate system, the map units will be in a more useful unit, such as meters or feet. Also, a projected coordinate system is flexible because it allows you to specify distances in units other than the map units by including an abbreviation with the value; you can only enter values in the coordinate system’s map units (typically, decimal degrees, as just discussed) when working with a geographic coordinate system.
The coordinate systems of the layers also need to match the coordinate system of the data frame. If the coordinate systems of the data frame and layers are different, the layers will be projected on the fly to the coordinate system of the data frame. Projecting on the fly can be problematic because it may cause unexpected alignment issues when making edits. For example, when editing, you may digitize some lines that look like they connect to other lines. While the lines appear to be snapped to edges when projecting on the fly, the lines may be dangling when you display them in their native projection. In addition, you cannot perform shared editing of coincident features through a map topology for layers that are being projected on the fly.
To avoid all these issues, make sure you are not projecting on the fly while editing. When you have an empty data frame, it automatically takes on the coordinate system of the first layer added to it. To change the data frame’s coordinate system, right-click the data frame name in the table of contents, click Properties, then click the Coordinate System tab. In the Select a coordinate system box, you can quickly set the coordinate system of the data frame to match that of a layer in it by clicking the Layers folder and navigating to the coordinate system listed underneath one of the layer names. Since the coordinate system of the data frame and the layers will now match, the layers will not be projected on the fly.
Starting an edit session
When you are finally ready to edit your data, turn on the Editor toolbar (if it’s not already displayed), click the Editor menu, then click Start Editing. This begins an edit session, which you will end when you are done. When you start an edit session on a geodatabase workspace, you have the ability to edit all the feature classes and tables in that geodatabase at the same time. With an edit session on a shapefile folder workspace, you can edit all the shapefiles that are stored in that directory.
If you start editing in a map that contains data from more than one workspace, you are prompted to choose the workspace you want to edit. On the dialog box, click a layer at the top to select its workspace source at the bottom of the window (notice that the database symbols change color), or click a workspace at the bottom of the window to view the layers in it at the top. Once you have picked the workspace, click OK to start the edit session. Later, if you need to edit data in the other workspace, stop editing, then start a new edit session and choose that workspace. Keep in mind that you can also right-click a layer in the table of contents, point to Edit Features, then click Start Editing, which automatically starts an edit session on the entire workspace containing that layer.
Once you choose the workspace to edit, sometimes you may see another dialog box appear about problems that ArcMap encountered when you started editing. This dialog box will list the layers that are being projected on the fly, as well as any other issues such as missing licensing, layers that cannot be edited because they are read-only or inside a basemap layer, and so on. You can double-click each message to open a help topic with more information.
For more on the Catalog window, projection considerations, and edit sessions in ArcGIS 10, see the following:
What’s new for accessing your data in ArcGIS 10
About editing data in a different projection (projecting on the fly)
About edit sessions
When you want to create features in ArcGIS 10, you’ll use feature templates. Feature templates have properties that define all the information required to create a feature. Effective use of feature templates can help make your editing easier and more efficient. See the earlier post, “Getting started with creating features in ArcGIS 10,” for an introduction to feature templates.
When you first begin an edit session, ArcMap helps you get started with feature templates by creating some for you based on the current symbology in your map. At this point, you should review the feature templates and refine them for your particular editing needs. You can click the Organize Templates button on the Create Features window to open the Organize Feature Templates window, where you can manage feature templates and their properties.
If you know you won’t be creating features in some of the layers, delete the extra feature templates to make it easier to find the templates you will be using. If you need to make new feature templates, start the Create New Templates Wizard. The wizard walks you through the process of making templates: first, choose the layer or layers, then, if applicable, choose any or all classes (based on symbology) within that layer to make into individual templates.
Feature template properties
Once a feature template is created, you can review and set its properties on the Template Properties dialog box. In particular, you should specify (1) some text to help organize your templates, (2) the default tool used to create features using that template, and (3) the default attribute values for the new features. Two of the items on the Template Properties dialog box, the target layer and the preview of the drawing symbol, are set for you based on the layer information and cannot be changed there.
Let’s say you are digitizing new buildings. How should you set up your feature templates? The following sections provide examples of how you might specify the properties in this scenario.
Feature templates have a name, description, and tags that can help you find them. To identify a template easily, give it a clear and descriptive name. For example, naming a feature template Buildings is too generic if you are creating different kinds of buildings. Naming a feature template Buildings – residential makes it easier to locate the feature template you should use when creating residential structures. Enter a description to provide additional information about the contents and intended use of a particular template. The description also appears as ToolTip pop-up text when you rest your pointer over a template on the Create Features window. In addition, you can add tags to a template. A tag is generally a short keyword, metadata item, or any other term that helps identify a template when searching for it. Tags can be used as a form of categorization so only the templates that meet certain criteria are displayed on the Create Features window.
Another property of a feature template is the default tool, which is the construction tool that automatically becomes active when you choose a feature template on the Create Features window. Setting the most appropriate default tool can help you avoid making an extra click to choose a different tool in cases where the Line or Polygon tools are not the primary ones you will be using. For example, when you are drawing rectangular building footprints, set the template’s default construction tool to Rectangle so that tool automatically becomes active instead.
Default attribute values in feature templates
The most significant feature template properties are the default attribute values, since setting them can really save you lots of time and improve accuracy. When creating residential building features, you should set the default building type to Residential so that the value is automatically populated in new features created with that feature template. Any default values that are already set up in your geodatabase are included automatically in the feature template properties as well. However, any ArcGIS system fields, such as Shape_Length or OBJECTID, and fields storing COGO values, are not shown on the Template Properties dialog box since ArcGIS supplies those attribute values. You can click the buttons above the attribute grid to change how fields are listed, such as to display all or only visible fields or to list fields by their names or aliases.
When choosing which default attribute values to set in a feature template, you should not provide a default value for fields such as a name or ID code that would not be common to many features. For fields that should have specific content, add the individual attribute values after you have created the feature. Otherwise, you will have to clear out the values assigned by the feature template every time you want to supply different attributes.
Once a feature is created, there is no link to the original feature template. For example, if you update the default attribute values of a feature template, those attribute values are not retroactively applied to existing features. Changes made to a feature template’s properties are only reflected in new features that are created with that feature template. To update the attribute values of a feature that has already been created, use the attribute table or the Attributes window.
Multiple feature templates for the same layer
A layer can have multiple templates associated with it, allowing each template to have different default attributes. If the Buildings layer had unique value symbol categories of residential, commercial, industrial, and so on, you could have three different templates with each one having a different default attribute for the type of structure. To create a residential feature, simply click the Buildings – residential template; the new features are automatically created as being residential and are attributed and symbolized properly.
You can also create multiple templates for a layer even if you are symbolizing with a single symbol. For example, if you are creating lines to represent pipeline features, you could create several feature templates with different default attributes for the common types of material or diameter sizes. You can create the feature templates quickly by copying the existing pipeline feature template. Simply right-click the feature template on the Create Features window, click Copy, open the properties of the copied template, then change the default attributes to another material or diameter.
Missing feature templates
What if the feature templates you want to use are not displaying on the Create Features window? The most common cause is that the layer is not being displayed on the map. When a layer is not visible because it is turned off in the table of contents, is beyond its visible scale range, or does not satisfy the current definition query, its associated templates are hidden. You need to make the layer visible again before you can create features in it. In addition, if you added a layer to the map or changed the symbology significantly after you started an edit session, ArcMap would not have created those feature templates automatically. You need to create them yourself with the Create New Templates Wizard.
To illustrate this, the graphic below shows the Table Of Contents window with layers listed by visibility and docked next to the Create Features window. Notice that feature templates for only the Visible layers are shown on the Create Features window. The feature templates are hidden for the National park boundary layer, which is listed under Out of Scale Range because the layer does not draw at the map’s current scale, and the Trails layer, which is turned off completely. The feature templates for these layers will appear again on the Create Features window once the layers are displayed on the map. There are no feature templates for Basemap, since it is not an editable vector layer.
Reviewing and saving feature templates
Working with feature templates is a dynamic process. As you are editing, review your feature templates periodically to make sure they are as useful as they can be. If you find that you repeatedly switch from the default tool to a different one or have additional attribute values that would make good defaults, you should update the properties of the template. In addition, if you add a layer to your map or add a symbology category (such as for a layer drawn with unique values), you need to create templates to be able to add features in that layer. In some cases, if you have changed the rendering of several layers since the templates were initially created, it may be best just to delete them and start again so the templates are synchronized better with your current symbology.
When you save your map document, the feature templates are saved in it, too. The next time you open the map and start editing, your feature templates will be there to help you be more productive when creating features. They are also saved with layer files, layer packages, and map packages and are available as part of feature services in Web editing applications so that other users can access your feature templates.
For more tips on feature templates, see the Web help topic, Best practices for using feature templates.
Content provided by Rhonda
Esri is pleased to announce the launch of the new Data Reviewer Resource Center! We are excited to provide the GIS community with a central location for information on ArcGIS Data Reviewer for improving your GIS data quality. You can access templates from the Gallery that are built around the ArcGIS Data Reviewer extension. Our goal is to make it easier for you to use our software throughout your quality control life cycle.
The Data Reviewer blog is an important part of the resource center designed to bring you the latest information specific to data quality processes and tools. This is a virtual space for everyone to communicate, collaborate, and share knowledge. Feel free to interact with your peers as well as post your own tips, comments, and questions. Your input will help guide us in our own efforts to better serve you. We’ll be posting information continuously, so please check back regularly, or sign up for our feed by simply clicking on the RSS 2.0 link to the left.
We hope you’ll find this blog dynamic, engaging and instructive. Come and explore the new Data Reviewer Resource Center!
The Data Reviewer Team
When you open the Editor toolbar in ArcGIS 10, you’ll notice that the toolbar looks different. For starters, there is no task list and no target layer list. So how do you add a feature without them? In ArcGIS 10, you use the new Create Features window, which contains all the elements you need. The workflow to create features is the same whether you are editing geodatabases or shapefiles or using an ArcView, ArcEditor, or ArcInfo license.
Introducing feature templates and the Create Features window
When you start editing, the Create Features window opens vertically and docks on the right side of your ArcMap application. The top of the Create Features window lists the feature templates in your map. A feature template is a new concept at ArcGIS 10. It is somewhat like setting the old target layer but is more powerful than that because it contains properties about how new features should be created: the target layer (feature class) where a feature will be stored, the attributes that a feature is created with, and the default tool that is used to create that feature. Feature templates also have a name, description, and tags that can help you find and organize them. You can review and set these on the Template Properties dialog box, which you can open by double-clicking a feature template on the Create Features window.
ArcMap automatically creates feature templates for the layers in the current editing workspace the first time you start an edit session in a map. Feature templates are based on the symbology of the layer, so you can have more than one feature template per layer. One feature template is created for a layer symbolized with the single symbol renderer, but a layer drawn with unique values gets a feature template for each symbol category. For example, if you have a layer of roads, a new feature template is created for each symbol type: freeway, major road, local road, and so on. The feature templates have the same target layer property but different road type attributes. This way, if you create a new feature using the freeway feature template, the attribute for the road type is automatically assigned as freeway. The new feature will also be symbolized correctly as a freeway.
The graphics below show the Layer Properties > Symbology tab listing the unique values symbols used for a Roads layer and the resulting feature templates in the Create Features window. Since the Roads layer has three unique values categories, three feature templates are created, where each one has a different default attribute value for the road type (Freeway, Major road, or Local road).
The bottom panel of the Create Features window lists the tools available to create features for the kind of feature template you have selected at the top of the window. For example, if you click the Springs point feature template at the top of the window, the construction tools will change to tools used to create points. If the Freeway line feature template is active, only construction tools that create lines are listed, as shown below.
Creating features with feature templates
So, simply put, to create a feature, choose a feature template at the top of the window and a tool at the bottom of the window. Each feature template has a default construction tool that is automatically activated when you choose a feature template, but you can click a different construction tool in the list to use instead. If you want to create a point representing the location of a spring water feature, simply click the Springs feature template and the Point tool, then click the map where you want to add the point.
To digitize segments as you did with the Sketch tool in previous releases, click a line or polygon feature template, then use the Line or Polygon tool to click the map where you want to place vertices. Straight segments are created by default as you click, but you can change the segment types using the palette on the Editor toolbar or Feature Construction mini toolbar. The Feature Construction toolbar follows the pointer as you click to give you easy access to commonly used tools. If the toolbar gets in your way while digitizing, press the TAB key to reposition it.
The process for creating annotation and dimensions is the same as for other feature types, so the Annotation and Dimensioning toolbars are not found in ArcGIS 10 since the tools have been integrated with the Create Features window. To create annotation, choose an annotation feature template on the Create Features window and a construction tool, such as Horizontal or Straight. When you click the feature template, the Annotation Construction window appears so you can enter the text of the new annotation, control how the text is placed, and set any additional symbol properties.
Feature templates and editing commands
Feature templates are also used when you are creating features with editing commands, such as Copy Parallel, Buffer, and Union on the Editor menu. In these cases, you set the feature template on the dialog box that opens when you click the command; you do not use the Create Features window. Choosing the feature template on the command’s dialog box specifies the target layer and the default attributes for the new features that will be created. To change the feature template, click the Template button to open the Select Feature Template window and click one of the available feature templates. Editing commands that can only output one type of geometry, such as Copy Parallel for lines, list templates just for that layer type. Commands that can output a variety of layer types list any existing templates that are the proper types.
When copying and pasting features, a dialog box appears immediately after you click the Paste button, allowing you to set the target layer. When you paste, you can choose an actual layer, rather than a feature template, so you can retain the attribute values from the copied feature instead of using default attributes. If you are just editing an existing feature, you do not need to specify a feature template.
To learn more about editing in ArcGIS 10, see these help topics:
Content provided by Rhonda