How Do I Use The Polygon Tracing Tool

How do I use the polygon tracing tool?

Overall processing workflow

The main processing workflow of using the Geocoding Correction Tool is composed of two portions, pre-processing applied to the input database, and the processing of the records. In the pre-processing phase, the database is geocoded with a geocoder, and the required columns are added. This can be done automatically with the Geocoding Service within the Web Toolset, or the user can to do it themselves. In the processing phase, after the database is uploaded, the schemas for the tables must be defined, i.e., the variable names, locations and content for input and output within the uploaded databases need to be identified to the system, and then the records can be worked on. The next figure depicts the case where the user geocodes the data themselves and then uploads it to the Web Toolset.

Database processing workflow

The general database processing workflow is depicted in the next figure. First the database is chosen, then the table must be chosen and have its schema defined, then the qualities to work on are selected, then the records are chosen, and finally each is processed.

Record processing workflow

The record processing workflow consists of choosing a record, creating an updated geocode by either moving the original point or adding new ones, moving the updated geocode around, saving it and then selecting another record and repeating, as depicted in the next figure. Obviously, one could choose to leave the original geocode “as is”, and this has been excluded from the diagram.

User interface

The user interface of the Geocoding Correction Tool has been developed as a webpage and is displayed in the next figure. It is composed of three main sections: the map (top left), record selection (bottom), and current record display, visible points, and other tools (right).

Query selection

A user performs a query to select records for processing from the database using the query panel, the components of which are displayed in the next figure.

The Geocode Correction Tool allows the user to select records to work on based on classes of qualities. In the Geocode Quality Panel figure only records with quality “QUALITY_CITY_CENTROID” (in this example database table) will be selected and displayed.

The qualities present in this dropdown will be a list of the unique qualities within the input database table (i.e., the result of a “SELECT DISTINCT (qualities)” SQL query on the input table). These will be specific to the geocoding engine used, with each geocoder possibly outputting different classes of coordinate qualities. In the present version, these qualities must be a field in the input table.

The user can choose the amount and type of records (e.g., non-processed only) to display per page on the panel in the figure.

Clicking on the database details icon will show a page displaying the statistics about the selected database including the total, completed, and remaining number of records broken down by quality type, as shown in the next figure.

Records panel

After clicking Get Records, the number of records selected will be displayed on the Records Panel as in the next figure, with the currently selected record highlighted in orange. The records can be sorted by the column headings by clicking on the appropriate heading. The pages or records can be scrolled through by clicking on the First, Prev, Next, and Last buttons or the page numbers below the records table. Clicking on a record in the list will select it and load it into the current record panel.

The details icon will open the details page shown in the next figure, from which all processing information associated with ca record can be reset.

Current record panel

When a record is selected, its information will appear in the Current Record Panel and its associated original geocoded point and all polygons that have been created will show in the Map Panel, as shown in next figure.

The Current Record Panel alone is depicted in next figure, which shows the information associated the current record.

From the Current Record Panel, the user can navigate to the First, Prev, Next, and Last records by clicking on the first four buttons in the next figure, respectively. The user can save the polygons on the current record and save and proceed to the next record by clicking on the last two buttons, respectively.

Key panel

The key panel displays the different type of objects that can be shown on the map.

Displayed features panel

The intial geocode associated with the record, as well as all the polygons a user has created or are in the process of creating will be listed in the Displayed points Panel, and displayed on the Map Panel as in the next figure.

The Displayed Points panel alone is depicted in the next figure.

The buttons in the following image are used to manipulate the polygons listed in the Displayed Polygons panel. a) is used to delete the current polygon that they user is in the process of drawing. b) is used to delete all polygons associated with the record. c) is used to close the polygon. d) is used to delete the last vertex that the user has drawn.

As a polygon is being drawn, the image on the left of the following figure appears. When the polygon is closed, the image on the right of the figure replaces it.

Also while a polygon is being drawn, the images in the next figure will be displayed alonside the the previous figure. These are the same images from above for a) closing the polygon, and b) deleting the last vertex that a user has drawn.

Map panel

The map panel displays a standard Google Maps interface, with a scale bar and several layers that can be selected, e.g., Map, Satellite, etc. Each of the geocodes from the current geocode panel will be displayed on this map. See the Google Maps Documentation for the basics of using the map interface (e.g., panning, zooming, overlay selection).

The small black box in the lower right corner can be used resize the map by clicking and dragging it while holding down the left mouse button, as shown in the next figure.

Drawing polygons

Single left-clicking on the map panel will create a new polygon vertex at that location. These newly added points will be displayed in orange. As more points are added, the polygon gets drawn from point to point.

This progression is depicted in the next few figures with the first showing the original geocode alone.

The next image is the outcome of clicking on a point to the north east of the geocode, resulting in the first polygon vertex being created.

The next image is the outcome of clicking on a point to the south east of the geocode, resulting in the second polygon vertex being created and the line representing the first side of the polygon being drawn.

The next image is the outcome of clicking on a point to the south west of the geocode, resulting in the third polygon vertex being created and the line representing the second side of the polygon being drawn.

The next image is the outcome of clicking on a point to the north west of the geocode, resulting in the fourth polygon vertex being created and the line representing the third side of the polygon being drawn.

The next image is the outcome of clicking the close polygon button, resulting in the fourth side of the polygon being drawn.

At this point, the polygon has been drawn completly. Clicking again on the map will start the creation process for another polygon.

Once the user has finished creating polygons for the record they should click on the Save button to save the polygons or the Save and Next button to save the polygons and proceed to the next records. These buttons are shown in the next figure, respectively.