Fuentes de datos1 2024

Understanding Data Sources in Geographic Information Systems

The Variety of Data Origins

• The origins of data used in Geographic Information Systems (GIS) can be highly varied, influencing how the data is collected and subsequently utilized.

• Distinction is made between base cartographic data and other types of data such as crime reports or incident calls from emergency services.

Sources of Base Cartography

• Base cartographic data can be sourced from official entities like the National Geographic Institute in Spain or local municipal corporations.

• Collaborative mapping platforms, such as OpenStreetMap, also provide alternative sources for base cartography.

Formats and Types of Collected Data

• Collected data may come in various formats including Word documents, PDFs, scanned images, Excel spreadsheets, and databases like Access or SQL Server.

• Data can be aggregated (e.g., total counts by municipality) or individualized (e.g., specific incidents).

Collection Methods for Incident Data

• Incident data may originate from fieldwork conducted by police forces or through surveys using electronic devices for data capture.

• Automatic exports from call center software (e.g., 112 emergency services) are another source but often require format conversion.

Processing Secondary Data for GIS Use

• Most collected data is considered secondary; it requires manipulation before being usable within a GIS framework.

• Initial steps include error cleansing to eliminate inaccuracies and redundancies in the dataset.

Standardizing Data Fields

• Normalization of field names is crucial; this includes removing accents and spaces while using underscores to ensure compatibility with GIS systems.

• Geocoding involves adding spatial coordinates to datasets to enable geolocation capabilities within the system.

Best Practices for Form Design

• When capturing information via paper forms, predefined fields should minimize free-text entries to reduce errors during digital input later on.

• Electronic forms should utilize dropdown lists for address entries to avoid common mistakes associated with manual text entry.

Common Errors in Data Entry

• Examples illustrate frequent errors encountered when entering incident information into spreadsheets, highlighting issues like redundancy.

Transcript Summary Issues in Data Entry for Accident Descriptions

Common Errors in Data Entry

• The transcript discusses the redundancy of having both a municipality field and a municipality code, suggesting that one could be eliminated as they convey the same information.

• It highlights common mistakes in accident description entries, such as variations of "arrollamiento a peatón" (pedestrian run-over), which are written differently but mean the same thing. This inconsistency can lead to confusion.

• Emphasizes the importance of minimizing the number of descriptions while ensuring clarity. Excessive or unclear information can introduce errors rather than aid understanding.

Challenges with Field Names and Geolocation

• Discusses issues related to field names, recommending avoiding complex naming conventions that may cause software errors during data processing.

• Points out that many location fields lack precise geolocation capabilities, often only providing vague references like avenues or intersections instead of exact coordinates.

Solutions for Data Management

• Suggests manual geolocation as an option by searching for coordinates using mapping layers, or alternatively, aggregating data by municipality to create thematic maps due to limitations in extracting specific location data.