GIS Location Data
In some applications, there is a wizard question if geo-code data should be retrieved from a third-party provider (Location IQ). If this option is activated, the page GIS Location Data becomes part of the workflow. The purpose of this page is to help the user inspect and adapt the data to get the correct coordinates for the locations.
In order to use this, you need to provide data for all or some of these attributes:
The Country or Country Code attribute is mandatory, while in general it would be good to have at least City or Postal Code, and State if that is relevant for that country.
The Postal Code works best in combination with Country Code, as in that case a specific postal code logic will be activated, which in general produces better results. The country codes should come from ISO 3166-1 alpha-2 codes, and the model will verify that the provided country codes are in this list.
Once you open the page, you see the locations for which the coordinates are still needed, via checkbox Request Geo-code, in table Location Data. You can retrieve the Geo-coordinates for all the selected locations via the page action Retrieve Geo-coordinates. This uses the Street, City, Postal Code, State, and Country to obtain the coordinates, together with more details on that location. Once you have inspected those results, you need to save them via the Save Location Data page action menu. This saves the data so that it can be retrieved the next time you are loading this Excel file.
On this page, you also have the ability to filter the locations by country via the Country Filter side panel. In this filter, you see the name of the country followed by something like (5 of 9 locations). The 5 indicates the number of locations for which we don’t have geo-coordinates yet, and the 9 indicates the total number of locations in that country. Initially, all countries will be selected if you have 2500 or less locations, otherwise only the first country will be selected. The reason for this choice is that the map/pages become somewhat slow if you show too many locations.
This map displays all locations, for the selected countries, based on their coordinates. The location selected in the map or in table Location Data is highlighted in green. It can help you to inspect the solution provided by the geo-coding service. If a location has not been geo-coded, Data Navigator shows a red circle in the center of the earth, an visual indicator that data is still missing.
The table contains all locations, for the selected countries, together with detailed information on this location. There are three types of data in this table:
A checkbox to indicate if geo-code data needs to be retrieved.
Status column: The status column is in general empty, but will show any errors/warnings that occurred during the determination of the coordinates.
The input data that describes this location: Street, City, Postal Code, State, and Country. This data can be edited if that is needed to get better results.
Output data from the geo-code service. This includes Longitude, Latitude, Importance, Size, Count, Name, Class, Type, Date, City, State, Country, Postal Code, Country Code.
Importance: According to Location IQ Calculated importance of this result compared to the search query the user has provided. Ranges between 0 and 1. (Source: https://locationiq.com/docs). Where 1 is best, and 0 the worst.
Size: A measure of the size of the location. The smaller this value is, the smaller the region is that describes the location. This value is larger if you are geo-coding a country but should be smaller if you are geo-coding a city.
State, Country, Postal Code, Country Code: These output values can be compared to input values to determine the quality of the solution.
Count: The number of geo-coordinates that are returned for this one location.
Once Data Navigator has retrieved the coordinates of the locations, you need to review the results to make sure they are correct. In most cases the results with an Importance of 0.3 or higher are correct. In case the value is lower, you should inspect the results in more details. You can check to see if the size is comparable to similar location, and if the Name, Class and Type make sense. However, this does not hold when the the specific postal code model is activate (by providing just the Postal code and Country code), as the importance will always be 0.1. (You will also see that the Output Class is “place” and Output Type will be “postcode”).
The header of this table contains the number of locations for which Request Geo-code is checked and the number of locations that still have to be geo-coded. This table also has four widget actions:
Show Selected Location Only: If you click this, the table will only show the data for the selected location.
Request Geo-code for selected locations in table: Set Request Geo-code for all locations for the selected countries (all locations visible in the table).
Request Geo-code for selected non-geocoded locations in table: Set Request Geo-code for all locations, that have not yet been geo-coded, for the selected countries (the locations visible in the table).
Empty Request Geo-coded: Empty Request Geo-code completely.
The geo-code service can return multiple places. The model picks the one with the highest importance, but it shows alternative places as well. In the map and table on the right part of the screen, you see details of the alternative places with respect to the location selected in the left part of the screen. In the map, you see those alternative places. The node that is used in the table on the right is marked in green, and the selected node is marked in orange. In this map, you also see a green rectangle. This is the smallest box that covers the complete location. The size that was mentioned earlier, is the length of the diagonal in kilometers.
The data in the table is the same as in Location Data table, see above, but now for alternative places.
Once you select a node in the map or a row in the table, you can click the right mouse menu Use this place instead. In that case, this place is used in the table on the left and going forward.
As mentioned before, it is important to click the Save Location Data page action, so that this data is stored. Only after you click this, the page will get the completed check-mark in the workflow.