Layer Operations

Several common GIS layer operations are available using the eRAMS GIS interface. Layers can be added, animated, organized, downloaded and extracted. Metadata can be generated and modified. Folders can be created, organized and shared. Users can also create and manipulate layers made from existing table information with options to join information from features that are spatially related. Use the Raster Calculator to create new rasters using mathematical functions and expressions between different raster layers.

eRAMS Layer Operations

General

Users can select from several common operations when working with layers in the eRAMS GIS interface. Layers can be added, animated, organized, downloaded and extracted. Metadata can be generated and modified. Folders can be created, organized and shared.

Add

Add new layers to a map project. Click on Spatial Layers in the Geospatial/User/Project Layers tab in the Map pane. There are three options for adding layers:

Add Feature Dataset – click on Add Feature Dataset, which opens an Upload Layer pop-up window. Click Add and browse to the location of the vector feature datafile of interest. Zipped files can be added directly. Click on the file then click Open. The file will be processed and added to the Geospatial/User/Project Layers tab in the map pane.
Add Raster Dataset – click on Add Raster Dataset, which opens an Upload Layer pop-up window. Click Add and browse to the location of the raster datafile of interest. Zipped files can be added directly. Click on the file then click Open. The file will be processed and added to the Geospatial/User/Project Layers tab in the map pane.
Add Datasets from URL – click on Add Datasets from URL, which opens a pop-up dialog box prompting to Enter a URL with the zip file for downloading. Click in the box and enter the address for the zipped file. Click Ok. The file will be processed and added to the Geospatial/User/Project Layers tab in the map pane.

Animate

The Animate tool allows automated display of a sequence of layers. Click on Spatial Layers under the Geospatial/User/Project tab on the Map pane and click Animate. The Layer Animation pop-up window opens displaying the Frame manger box and the Legend box.

Create

To create a new polygon, point or line feature layer, click on the Spatial Layers heading under the Geospatial/User/Project Layers tab of the Map pane to open the pop-up context menu. Click Create Layer and select which type of geometry you want to create:

Polygon layers are created by selecting Polygon from the menu and Entering the name for the new layer: in the text box that appears in a pop-up dialog box. Click Ok. A new polygon layer will be added to the Geospatial/User/Project layers tab of the map pane. The attributes table for the polygon layer will be empty.
Line layers are created by selecting Point from the menu and Entering the name for the new layer: in the text box that appears in a pop-up dialog box. Click Ok. A new line layer will be added to the Geospatial/User/Project layers tab of the map pane. The attributes table for the line layer will be empty.
Point layers are created by selecting Point from the menu and Entering the name for the new layer in the text box that appears in a pop-up dialog box. Click Ok. A new point layer will be added to the Geospatial/User/Project layers tab of the map pane. The attributes table for the point layer will be empty.

Copy

To copy the current layer to a new layer, click on the layer and select Copy from the pop-up context menu. A pop-up dialog box will open allowing re-naming of the copy, if desired by clicking in the text box and entering a new name. Click Ok to copy the file and add the copy to the Geospatial/Users/Project Layers tab.

Delete

To delete a feature layer or table from the Geospatial/User/Project Layers tab under the Map pane, click on the feature of interest. In the pop-up context menu select Delete. A pop-up dialog box will open asking if the layer really should be deleted. Click Ok to delete or Cancel to keep the file.

Select

The Selection tool in the pop-up context menu is active when a selection has been made from a layer and acts to zoom to the selected feature, clear or reverse the selection, or create a new layer from the selection.

To use the Selection tool, a selection must first be made in a feature layer of interest. This is most commonly done using the Select by Attribute and/or Location tool in the Map Menu bar or from the layer’s attribute table. Next, click on the feature layer of interest to open the pop-up context menu and select Selection, then click on one of the available options. These include:

Zoom to Selected, which will zoom the map view to the extent of the selected feature(s).
Clear Selection, to clear the selection.
Reverse Selection, to select all other attributes other than the one originally selected.
Create Layer from Selection, to create a new layer. Clicking on this option will open a new pop-up dialog window prompting Copy layer to: which can be changed by clicking in the text box and entering a name for the new layer. Click Ok to complete the process and place the new layer in the Project Layers tab of the Map pane.

Download

Using the Download tool feature layers and tables can be downloaded for use in other applications. To download a feature layer, click on the layer of interest and click Download on the pop-up context menu. If a vector, select if the file should be downloaded in shapefile or GeoJSON format. Rasters are downloaded in Geotiff format. The layer will be downloaded as a zipped file in the desired format. Tables can be downloaded by clicking on the table of interest and selecting Download from the pop-up context menu. The file will be zipped and downloaded in comma-delimited format.

Extract Layer

Public data layers can be extracted for use as Geospatial/User/Project Layers. To extract Public Layers for use in subsequent analyses, click on the layer of interest under the Public Layers tab in the Map pane. Different options for selection will be available depending on the layer selected.

U.S. Census data are extracted by clicking on one of the available years or geographical divisions such as State, County, Tract, Block Group, or Block and clicking Extract Layer in the pop-up context menu.
U.S. Geo Data, U.S. Hydro Data, U.S. EPA Water, and Land Use Land Cover data are extracted by clicking on a layer of interest then clicking Extract Layer in the pop-up context menu

In all cases, a Data Extraction window will open. First select where the results will be stored by choosing Store results in a folder: from the drop-down menu to choose an existing folder, or by clicking New Folder. If New Folder is selected, a pop-up dialog box will prompt to Enter the name of the new folder: in the text box, then click Ok.

Select the Type of data, Groups: or Layers: to be extracted by using the drop-down menu(s). The Area of Interest can be specified by Selecting a region on the map.

A Point or Line buffer can be drawn around a feature on the map by selecting point or line buffer and specifying the radius by typing in the text box. Units are given in the units of the map setting. After specifying a radius, click on a point or line feature of interest in the map window to set the buffer for the map region of interest.
A user-created Polygon, Line, or Point can be drawn on the map by clicking on the desired option and clicking Select. Place the cursor in the desired location on the map and click to define a point and/or move the mouse and click again as needed to define the line or polygon of interest for clipping to. Double-click to complete the shape and add the shape to the Clipping Layer: list in the Clip Geometries pop-up box. To remove the shape, click Clear at the bottom of the region selection box.
A rectangular selection area can be defined by clicking on the map and holding down the mouse button while dragging to expand the rectangle.
An area from Within a Layer Extent: can be used by selecting from choices listed in the drop-down menu.
A Well-Known Boundary can also be used for clipping. With this option, the Select Well-Known Boundary pop-up box appears with a Boundary Type: drop-down selection menu. State, County, City, specific watershed hydrologic unit code (HUC) boundaries, and Zip Codes can be selected for clipping. After selecting the appropriate boundary from the drop-down menu by clicking on it, and refining the selection as needed with selections from subsequent drop-down menus, click Generate to extract the data.

Once the operation is complete, a pop-up window will document generation of the new layer, click Ok to close the pop-up dialog box window, and Close to close the Data Extraction box.

Metadata

Metadata, or information about data for Geospatial/User/Project Layers can be viewed, saved, and exported. To access and modify the metadata for any feature class layer or table in the Geospatial/User/Project Layers tabs of the Map pane, click on the object of interest to open the pop-up context menu. Click on Metadata to open the Metadata pop-up window. The window has three tabs where information about the data can be entered.

Under the General tab, brief abstract and purpose statements can be made by clicking in the text boxes. Citation information can also be added. Keywords can be added in the text box under the Keywords tab. Comments can be added in the text box of the Comments tab and posted to the metadata by user name.

To Save the additions, click Save. A Success pop-up dialog box should open when the additions are successfully saved. Click Ok to close the box.

To download the metadata, click the Export button. The Download pop-up box opens with a Download as: drop-down menu. The menu provides the option to save the metadata file in JSON format or in XML format. Select the desired format and click Download. Click the X in the upper corner of the Download pop-up box to close it and click Done to close the Metadata pop-up box.

Map Service Metadata

Map Service Metadata is provided to describe the public information provided in the Public Layers tab of the Map pane. To view the pre-populated information provided for public information, click on any layer under the Public Layers tab of the Map pane and select Map Service Metadata from the pop-up context menu. A pop-up Metadata window opens with a description of the data.

The metadata can be added to by clicking in the text boxes of the pop-up window and saved by clicking the Save button (is not saved if pop-up box reopened).

The metadata can be exported by clicking the Export button which opens another pop-up box with a Download as: drop-down menu. The menu provides the option to save the metadata file in JSON format or in XML format. Select the desired format and click Download.

Click the X in the upper corner of the Download pop-up box to close it and click Done to close the Metadata pop-up box.

Organize

Several common operations and features are available to organize your geospatial information. Click on the folder/layer/table of interest and select the desired operation to display the pop-up box and follow the prompts, then click “Ok” to add it to the Geospatial/Users/Project Layers tab. Users are able to:

Copy
Create
Delete
Download
Rename
Share

Folder Sharing

Individual folders in the User/Project Layers tab of the Map pane can be shared with other collaborators when the user is logged in to eRAMS or access can be limited by the creator by disabling sharing.

To enable sharing of a folder that was previously disabled, in the User/Project layers tab of the map pane, click on the folder of interest to open the pop-up context menu. Select Enable Sharing to allow access to the folder by other collaborating users.

To disable sharing of a folder in the User/Project layers tab of the Map pane, click on the folder of interest to open the pop-up context menu. Select Disable Sharing to block access to the folder by other collaborating users.

Raster Calculator

Raster calculator is used to create new rasters by executing mathematical functions and expressions between different raster layers. The raster Calculator tool can be accessed from the pop-up context menu by clicking on a raster of interest in the Geospatial/User/Projects tab of the Map pane and selecting Raster Calculator.

The Raster Calculator pop-up box opens displaying a list of Rasters available for analyses. The tool allows the user to build expressions that apply a mathematical operation or function to a selected raster or set of rasters. The applied function or operation will execute over each cell resulting in output of a new raster.

Double-click on the raster of interest to add it to the Output raster box at the bottom of the window. Functions can be added by double-clicking on any of the Functions: listed.
- Mathematical operators can also be added to the expression by clicking on the desired operator.
Click on the Calculate button. A pop-up dialog box will open displaying the New raster name: which can be changed by clicking in the box and entering a new name. Click Ok when complete. Click Cancel to close the Raster Calculator pop-up box.

Tables & Attributes

Working with tables and attributes is easy and intuitive. Users can create and manipulate layers made from existing table information with options to join information from features that are spatially related.

Create

To create a new layer from table information, click on the Tables heading or one of the tables listed under the Geospatial/User/Project Layers tab in the Map pane. If no table files are listed, a new layer cannot be created. If tables already exist, click on Create Layers in the pop-up context menu. A File Importer pop-up box will open. The Datum can be specified using the drop-down menu. The Coordinate System can also be specified in the following drop-down menu. Values for the X: and Y: fields can be selected from pre-populated attribute values based on existing tables.

Note: not all selectable fields selected will yield usable values for the creation of a new layer.

Once selections have been made for the X: and Y: fields using the drop-down menus, click Ok to create the layer.

Download

Join

The Join tool can permanently append attribute information from features that are spatially related and/or join attribute data to features or tables using a common field identifier from another feature or table. To use the Join tool, click on the feature of interest to open the pop-up context menu. Select Join. A second menu will open allowing selection of which type of join to be performed, Spatial or Table.

Spatial joins append attribute columns or fields from the joined feature to the selected feature. Rows will be matched and the nature of the join will dictate what information is appended in the rows, especially when joining different geometries. To perform a spatial join, click Spatial on the context menu. Select the layer to join to the layer of interest using the drop-down menu. Click Ok to perform the operation and close the pop-up window.
Table joins append attribute information to the selected layer from another table or the attribute table of another layer based on a common field identifier. To perform a table join, click Table on the context menu, which will open the Join Table pop-up box. Select the field of the layer of interest that the join will be based on using the drop-down menu. Select the table or layer to be joined in the next drop-down menu. In the last drop-down menu select the field from the table or layer to be joined. To make the joins permanent in the current layer rather than creating a new layer, click the checkbox. Click Ok to perform the join and close the pop-up window.

Open Attribute Table

Open Attribute Table on the pop-up context menu opens the attribute table for spatial feature layers and tables. Attribute tables contain tabular information about the geographic features of interest. To open the attribute table for a feature or table, click on the layer of interest to display the pop-up context menu. Click on Open Attribute Table to display the Layer Attributes pop-up window. The attribute table has several features and options which allow viewing, querying, editing, and saving data.

Each object in the layer is represented as one row or record of the attribute table, with columns representing different fields or attributes of the object. The number of rows displayed in the default window can be adjusted using the Page size: drop-down arrow to select between a minimum of 10 records and a maximum of all the records. To view the records and fields, use the scrolling bar at the bottom and sides of the attribute table pane. Additionally, use the page number text box to enter a page to jump to, or use the forward and back arrows and/or the beginning of the table or end of the table arrows to navigate.

The first column of the attribute table for the feature or table is typically a unique object identifier. By clicking on a row, a pop-up menu allows to Select the row or to Zoom to the row, or object, on the map. The radio buttons at the bottom of the window allow display of All of the records or only those Selected records. Multiple records can be selected by using the Select by Attribute and/or Location map tool found in the Map Menu Bar to query for multiple records. To deselect all selected records, use the Unselect All Features in All Layers map tool from the Map Menu Bar.

Each field or attribute column has multiple options available. The column can be sorted by clicking on the Up/Down arrows. Actions can be undone or redone by clicking on the Undo and Redo links. The Save link is used to save any changes to the attribute table. Other field options are accessed through a pop-up menu that displays when the field title is clicked on, these include:

Filter allows filtering of the field column by clicking on the column heading then clicking Filter. Chose from one of the pre-populated values to display that record only by clicking in the checkbox next to the value of interest then clicking Set Filter. To show all records again, click on the column heading then click Filter, and click Show All. A custom filter value can be entered by clicking on the column heading, clicking Filter, then clicking Custom Filter. A pop-up window opens allowing entry of a Custom filter value: by clicking in the text box and entering a value. Click Ok to apply the filter or Cancel to cancel the operation. Note that to display all records, the filter must removed from the field that the filter was originally applied to.
Rename is used to rename the field column heading. Click on the column heading and click Rename to open a pop-up window where a new Name for the column: can be entered by clicking in the text box and typing in the new name. Click Ok to rename the column or Cancel to cancel the operation.
Delete is used to delete a field, by clicking on the column heading then clicking Delete. The action can be reversed by clicking the Undo link at the top of the attribute table window.
Calculate is a field calculator. Clicking on Calculate opens the Field Calculator window. To use the calculator, click on an attribute of interest from the Layer Attributes: section of the window. Then select whether the operation will be Math or String using the radio buttons.
- If Math is selected, the available mathematical Functions: are displayed in the left pane of the window. Functions can be selected or combined with layer attributes in the Field= equations box using the mathematical operator buttons below the function pane.
- String functions include subsetting the string with substr, changing the case using toLowerCase or toUpperCase, converting the values toString, or trimming the values with trim. Entries can also be made directly in the equations box by clicking on it.
- Click Calculate to perform the selected operation and overwrite the values in the selected field with the results. To perform calculations in a new or empty field, use the attribute table Options to create a New Column.
Statistics for the field of interest can be generated by clicking on the column heading and clicking Statistics. A Summary statistics window will open displaying standard summary statistics for the field, including a Boxplot of the data and a Frequency plot. The number of data bins can be adjusted by clicking in the Number of bins: box and entering a new value, then clicking Update. The statistics results can be exported to a pdf by clicking the PDF button. Close the window by clicking Close.
Hide will hide a field column from view.
Properties displays properties about the field of interest.

Options

Options for attribute table functions are displayed by clicking on the Options link. These include:

New Column, create a new column by clicking on New Column to open an Add Column window. The new Column name: can be added by clicking in the text box. The Column type: can be selected using the drop-down menu. Types can be text, integer, date, datetime, and real. To create the new column click Accept. To cancel the operation click Cancel. To make any edits to a newly created column first click Save on the attribute table.
Query (advanced search) will open the Query Builder window. A query can be built through definition in the Attribute pane and/or in the Spatial Location pane moving between panes using the Next and Previous buttons at the bottom of the window.
- In the Attribute pane, the attribute of interest used in the query is selected using the drop-down window. Click Add to Query to add the selected attribute to the SQL-type Query box in the center of the Query Builder pop-up window. Logical and arithmetic operations including And, Or, and/or Like can be added to the new query by clicking on them. Attribute Values are added by clicking in the Value: box and typing in a value. The drop-down menu below allows selection of a sample value taken from the attributes table of the query layer. The Clear button can be used to remove the query.
- In the Spatial Location pane, a spatial query can be built between the originally selected layer and another geometry using relationships such as: intersects, within a distance of, touches the boundary of, within, etc. Spatial queries can also be built from selections by specifying a buffer radius and geometry type for the buffer
- To run the query click Run Query, to save the query for future use click Save Query.
  - Delete Selected Rows is used to deleted any rows that are selected. Use the Undo link to undo a deletion.
  - Metadata opens a Metadata window where under three tabs, General metadata information can be added, Keywords can be added, and Comments can be added for use by collaborators. Additions to the Metadata window can be saved by clicking Save or exported to a file using the Export button. Click Done to close the window.
  - Export will export the attribute table to a comma-delimited zipped file. Make sure pop-ups are not blocked in the browser to download the file.
  - Show All Hidden Columns will unhide previously hidden columns. Don’t know if this will work as Hide does not work.
  - Show Selected will display in the attribute table only those records or rows that are selected.
  - Show All will display in the attribute table all records, including any that are selected.
  - Add Coordinates will add X and Y coordinates as new columns, by default in decimal degrees, to the attribute table for each record.

Select Attribute to Visualize

The Select Attribute to Visualize option is used for U.S. Census data available under the Public Layers tab of the Map pane. This pop-up context menu tool allows selection and display of specific census attributes.

To select and display U.S. Census attributes using Select Attribute to Visualize, click on the year of interest or the geographical scale of interest under the U.S. Census Public Layer and click Select Attribute to Visualize on the pop-up context menu.

Three attributes can be visualized, Population, Population Density, and Households. For the Population and Population Density Attributes, further selections can be made for Total, Male, or Female on the additional pop-up context menu(s) that appear. For Households, additional attributes to be displayed include Number of Units and Size. The layers must be active to complete the selection tasks.

Visualize

Users can customize the look and feel of the GIS canvas by manipulating placemarks, labels, and features. Options are included to modify layer placement and transparency. Additionally, several zoom operations can be conducted to move between layers.

Display

Bring to Top/Bottom

In the Public Layers tab of the Map pane, the Bring to Top/Bottom tool moves a layer of interest to the top or bottom of the set of layers. Click on the layer of interest in the Public Layers tab of the Map pane. Then click on Bring to Top/Bottom to display that layer over/under other active layers.

Close/Open All

To Close/Open All contents in a folder, click on the folder of interest in the Geospatial/User/Project Layers tab of the map pane. The pop-up context menu opens, click Close/Open All.

Identify Features

The Identify Features option provides additional information about Public Layers. To use the Identify Features tool from the pop-up context menu, click on the Public Layer feature of interest to open the menu. The feature layer should be the top-most viewable layer in the map window. Then click Identify Features and click on a feature in the map window. A pop-up dialog box will open with the title of the feature of interest. Tabs and/or drop-down menu selections in the box will display more information about the feature. Click the X in the upper right-hand corner of the box to close it.

Transparency

To control the transparency of different Public Layers, click on the layer of interest to open the pop-up context menu. Depending on the layer type, the tool available will be Transparency or Transparency/DPI. To adjust the transparency of the layer features and/or the DPI or thickness of the linear features, use the bar slider to change the appearance of the object. Larger values equal more opaque or thicker features. To make features completely transparent or hollow, set the transparency at 0.

Placemarks & Labels

Add to Placemarks

The Add to Placemarks tool makes a new placemark based on the selected vector feature. To create a new placemark from a vector feature layer, click on the feature then select Add to Placemarks from the context/pop-up menu. The Choose Name Field pop-up box will open allowing selection of the layer field to use as the placemark name from the drop-down menu. Click Ok to create the new placemark, add it to the map and to the Placemarks tab of the Map pane.

Information about the placemark can be edited by clicking on the placemark either in the Map pane under the Placemarks tab, or in the map window. A placemarks pop-up box will open with options to Edit and/or zoom to the placemark. Clicking Edit will open the Placemarks Editor box. The box has three tabs:

General which has boxes for entering or modifying the title, description, location, elevation, and Longitude-Latitude: of the placemark. Depending on the type of placemark and information provided by the original file, some of these boxes may be pre-populated. The Edit Shape link allows for adjustment of the vertices of the shape though clicking and dragging of existing vertices. The Zoom link zooms and re-centers the placemark in the map window.
Symbol which allows adjustment of the placemark symbology. Symbol Style: settings may be altered: Opacity adjusts the object opacity, with 100 being fully opaque and 0 being fully transparent or hollow. Size adjusts the symbol size for point-type placemarks, and Hatch Size adjusts the thickness of hatched lines when the Shape: type selected is Lines. Placemarks with area can also be filled by a Solid color, selected by clicking the Color: swatch and selecting a new color from those swatches displayed, or by a Symbol. Lines and Symbol colors are changed using the Color: swatch for objects. For point placemarks, a range of symbol types are available for selection from various categories. After a selection is made, click Save to apply the edits.
Files allows the addition of files that can be linked to the placemark to provide more information for map users. Several types of files can be added, including documents and images.

Edits to the placemark can be saved and applied by clicking the Save button, then Close to close the editor. To remove the placemark, click Remove. A pop-up dialog box will open asking if the placemark should be deleted, click Ok to remove.

Turn Labels On/Off

Users can turn labels on or off to hide or visualize feature labels by clicking on the layer of interest under the Geospatial/User/Project tab to open the pop-up context menu. Click Turn Labels Off to hide the labels from the map view or Turn Labels On to make them appear in the map view.

Zoom Options

To access the zoom options click on the folder of interest in the Geospatial/Users/Project tab of the Map pane to open the pop-up context menu. Click on desired operation to change the spatial scale and view of the map to that of the layers within the folder. Options include:

Folder Extent – zooms the map view to the extent of the feature layer files in a layer folder.
Full Extent – used with Public Layers to zoom the map view to the extent of the selected public data layer
Layer – zooms the map view to the extent of the selected feature layer.
Visible Extent – used with Public Layers to zoom the map view to the extent of the selected public data layers that are visible.