Geocodificacion 2024

Geocoding Process Overview

Introduction to Geocoding

• Geocoding is the process of assigning geographic coordinates to map points, essentially determining the spatial location of an address.

• Addresses can be in alphanumeric format, including street name, number, city, postal code, province, and country. The software used will determine how these addresses are spatially represented.

Data Structure for Geocoding

• A table containing pharmacy addresses includes fields such as pharmacy name, postal code, location details (address), and a marked address suffixed with "OK" indicating it contains complete information.

• It is ideal to have address components separated so they can be combined based on the geolocator type being utilized. This allows for flexibility in data handling.

Requirements for Geocoding

• To geocode a set of addresses, a table storing the desired addresses and a locator (or composite locator) that divides the address into multiple fields is necessary.

• The tool matches addresses with the locator and stores each record's result in a new entity class of type point.

Using Geolocation Services

Types of Geolocation Services

• Two geolocation services will be used: ArcGIS Pro's paid service that consumes credits and Cartociudad from Spain’s National Geographic Institute which is free but more demanding on data processing.

Accessing ArcGIS Pro

• Upon starting ArcGIS Pro after entering access credentials, users see all previously executed sessions; this version is 33.2 which may differ from earlier videos shown during coursework but will soon be updated accordingly.

Security Measures

• Users must change their initial password to one known only to them; losing this password requires contacting support for reset procedures due to security protocols within the application.

Creating a New Project

Initial Setup

• On the home page of ArcGIS Pro, there are learning resources available including quick start tutorials covering basic functionalities like project creation and data exploration tools that help resolve common queries not covered in previous videos.

Starting a New Session

• Users create a new project by navigating to 'Map' and selecting 'New Project'. In this case, session 10 bis is created while ensuring proper storage locations are selected before proceeding with project setup.

Adding Data Layers

Importing Data for Practice

• The first step involves adding layers needed for practice; users should locate their downloaded data files before importing them into their workspace within ArcGIS Pro. In this instance, property crime incidents are being geolocated using provided datasets.

Understanding Data Structure

• The imported spreadsheet contains incident addresses along with columns detailing situation codes and cities; however, coordinates are initially absent as they need to be generated through geocoding processes later on.

• Key fields identified include 'address' and 'city', essential for successful geocoding operations moving forward.

• Right-clicking options reveal choices such as creating points from existing tables or initiating geocoding when no coordinates exist yet in the dataset.

• Selecting ‘geocode’ prompts instructions necessary for completing this task effectively within ArcGIS Pro environment.

This structured approach provides clarity on key concepts related to geocoding while facilitating easy navigation through timestamps linked directly to relevant sections of content discussed in detail throughout the transcript provided above.

Geocoding Process Overview

Step 1: Choosing the Locator Service

• The first step involves selecting a locator service, either global geocoding or a custom service. In this case, the choice is to use the service provided by ArcGIS.

Step 2: Data Consultation

• It is essential to consult data to determine how many fields are needed for geocoding. Ideally, having multiple fields enhances versatility; however, in this instance, only two fields are used: address and city.

Output Parameters and Limitations

• The output parameters include specifying the country to simplify geocoding processes. Limiting by category can also be beneficial but is not mandatory in this scenario. The focus remains on using the address as input for geocoding.

Data Input Configuration

Input Fields Specification

• The input table named "Sit" contains two fields: one for addresses and another for cities. This setup allows for effective processing of location data within ArcGIS's geographic database associated with each project.

Coordinate System Selection

• A projected coordinate system (UTM) will be utilized, specifically ETRS89 for Spain, which predominantly falls under zone 30 across most of the peninsula. This ensures accurate spatial representation of locations during geocoding operations.

Geolocation Execution

Country Specification and Credit Consumption

• When prompted about the country, Spain is specified as the target location for geocoding services. It's noted that using these services consumes credits—virtual currency required by ArcGIS—which may limit usage based on availability during educational projects or assignments.

Geolocation Results Analysis

• Upon execution of the geolocation process, results indicate 40 points with an 81% match rate; however, some points lack clarity regarding their exact locations. Users have options to refine these results further if necessary but may choose not to do so at this stage.

Visualizing Geolocated Data

Background Map Adjustment

• To enhance visualization of geolocated points on a map, users can switch background maps—for example, from default settings to OpenStreetMap—to better assess point placements visually against known landmarks or features in Elche city area.

Exporting Geolocated Data

• After confirming correct placements of points on the map, users can export their data into a shapefile format named "tabla_geocodificar," allowing them flexibility in saving and utilizing this information outside ArcGIS environments as needed later on in their projects or analyses.

Utilizing External Geolocation Services

Connecting with Carta Ciudad Service

• The next phase involves accessing an external web-based service called Carta Ciudad for additional geolocation tasks where users download a template from Instituto Geográfico Nacional (National Geographic Institute), fill it out according to specific conditions, and submit it back for processed outputs that are then returned with geographical coordinates attached based on user inputs provided earlier in their submissions.

Unified Address Calculator Overview

Introduction to the Unified Address Calculator

• The unified address calculator offers two main functionalities: obtaining geographic coordinates from postal addresses and retrieving postal addresses from geographic coordinates.

• Input files must be in CSV format, which is a comma-separated values file provided on the website.

File Requirements and Processing Instructions

• The service requires a properly formatted CSV file where each row can either encode direct or indirect information based on whether postal addresses or geographic coordinates are provided. It can process up to 60,000 records at once.

• A critical requirement is that the separator used in the CSV file must be a pipe (|), not commas or semicolons, which are commonly generated by applications like Excel. Users need to adjust their files accordingly.

Mandatory Fields for Input Files

• Essential fields include: type of road (e.g., street or highway), name of the road, portal numbers (1 and 2), postal code, population, and municipality INE code; these fields must be included even if they are empty. Additional fields may also be added as needed.

• Detailed instructions clarify how each field should be filled out; for instance, if using kilometer points instead of portal numbers, users should input those correctly in place of standard numbering.

Template Download and Formatting Guidelines

• Users can download templates in either CSV format or Excel format; it is recommended to use Excel for ease of data entry while ensuring no special characters or accents are included due to system sensitivity.

• An example spreadsheet illustrates how various combinations of streets with different codes can coexist within one document while maintaining proper formatting standards for successful geolocation processing.

Execution and Result Analysis

• After preparing the input file correctly (in UTF-8 encoding with pipe separators), users execute the program by selecting their file to obtain results successfully converted into a new output file containing geolocated data.

• The processed output includes additional information such as latitude and longitude along with any observations regarding address validity—indicating exact matches or nearest alternatives when necessary. This method proves efficient for handling large datasets during projects like master's theses while emphasizing careful attention to detail in street naming conventions.

Final Steps: Adding Geolocated Data to Sessions

• Once geolocation is complete, users add the processed CSV back into their project session; this step involves creating event layers based on identified latitude and longitude fields from the table generated by CartoCiudad's processing toolset.

Geolocation Techniques Using Open Source Tools

Setting Up Spatial Reference and Layer Creation

• The spatial reference system used is WGS84, which is essential for geolocation tasks. A new layer named "carto ciudad dos" is created to manage event data.

• Initially, the data points are located in Madrid, while others are found in Alicante. This indicates a diverse geographical spread of the data being analyzed.

Exporting Data Layers

• The layer is exported to a local file named "cartociudad dos," allowing for better management and accessibility of the geospatial data.

• After creating the new layer, unnecessary layers are removed to streamline the workspace and focus on relevant data.

Zooming In on Specific Locations

• A zoom function is utilized to examine specific addresses within the dataset, such as General Bonanza 5, highlighting the importance of detailed examination in geolocation tasks.

• When attempting to view portal numbers on streets like General Bonanza, it becomes evident that not all information may be available or visible at first glance.

Understanding Data Completeness and Sources

• The visibility of police numbers depends on user contributions within collaborative mapping platforms like OpenStreetMap. This emphasizes how community input shapes available geographic information.

• The session concludes with an overview of using two geolocation systems: ArcGIS's geolocator and Carto Ciudad's tools, showcasing their complementary roles in effective geolocation practices.