Understand Spatial Data and Mapping Workflows
Introductory information about geographic information systems, spatial data and mapping, plus free tools for everyday conversions.
Free geospatial converters
Coordinate converter
Convert latitude and longitude between decimal degrees and degrees, minutes, seconds.
Converts notation only, on the same datum. It does not transform between datums such as Minna and WGS 84, which requires appropriate parameters.
Land area converter
Convert an area, or calculate it from rectangular plot dimensions.
For general guidance only. Plot sizes referred to locally as “a plot” vary by area and should not be used as a measurement unit. Survey-derived areas take precedence.
GIS fundamentals, explained plainly
What Is GIS and How Is It Used?
A Geographic Information System stores, manages, analyses and displays information linked to locations. Organisations use GIS to understand where things are, how they relate to one another and how they change over time, from land parcels and utility networks to land use and infrastructure assets.
Understanding Coordinate Reference Systems
A coordinate reference system (CRS) defines how coordinates relate to real positions on the Earth. Datasets in different systems must be transformed with appropriate parameters before they can be combined. In Nigeria, projects may encounter both the national Minna datum and global WGS 84-based systems, so documenting the CRS of every dataset is essential.
Geographic Data Formats and Their Uses
Spatial data comes in vector formats (points, lines and polygons, such as shapefiles, GeoPackage or KML) and raster formats (grids such as imagery or elevation models). CAD formats such as DWG and DXF are common for drawings. Choosing the right format depends on how the data will be used and by whom.
How Spatial Data Supports Infrastructure Planning
Infrastructure planning depends on knowing terrain, existing assets, land use, access and constraints. Integrating these layers in a GIS lets planners compare options, identify conflicts early and communicate proposals clearly.
GIS Data Quality and Validation
Spatial data quality covers positional accuracy, attribute accuracy, completeness, logical consistency and currency. Validation checks such as topology rules, attribute domains and comparison with control help ensure data is fit for purpose.
Using Maps for Land and Asset Management
Maps turn records into a picture that people can act on. Linking land parcels or assets to attributes such as ownership references, condition and maintenance history helps organisations plan, prioritise and report.
Preparing Data for GIS Integration
Before integration, gather source files, confirm their coordinate systems, document their origin and date, and agree a common attribute structure. Clean, documented inputs make integration faster and results more reliable.
A note on technical resources
Technical resources should identify applicable software versions, coordinate systems and assumptions where relevant. Ask us if you need guidance specific to your data.
Have spatial data that needs organising?
Our GIS team can help you convert, integrate, analyse and document your datasets.