Spatial data

Also called: Geographic data · Topic: Remote Sensing, GIS and GNSS · NCERT: Class 12, Ch 4 "Spatial Information Technology"

Meaning

Spatial data (also called geographic data) is data about a feature that is tied to a fixed place on the earth and registered to a coordinate system (a fixed grid of latitude–longitude or map coordinates). Each piece of it can be found on a map. It matters because it is the "where" part of any geographic question. A GIS (geographic information system) needs it to answer what is where, why it is there, and what happens if it changes.

Explanation

How spatial data works

• Older tools could not handle location properly:
• A DBMS (database management system: software that keeps data in tables of rows and columns) knows "what" but not "where".

• Computer-assisted cartography (drawing maps on a computer) knows "where" but cannot work out "why" or "what if".

• Spatial data fills this gap:

• Every record carries a location, such as latitude and longitude or map coordinates.

• Because of this, the record can be drawn on a map, measured and compared with other places.

• Result: a GIS can capture, store, check, combine, analyse and display data that are spatially referenced (each piece of data is linked to a real place on the earth).

Spatial data vs attribute data: the two forms of geographical information

Form	Meaning	NCERT Box 4.1 example
Spatial data	Tied to a location and registered to a coordinate system	State-wise literacy rates: each state has a place on the map
Non-spatial / attribute data	Describes a feature but has no location of its own	A cycle shop's stock register (models, prices, quantities)

• GIS links the two. The outline of a state (spatial) is joined to its literacy figure (attribute). This joining is what makes analysis possible.
• Trap: the same table becomes spatial once each row is tied to a place. A literacy table counts as spatial because "Kerala" or "Bihar" can be found on a map.

Three forms of spatial features (NCERT Fig. 4.1)

In a GIS, every real-world object is stored as one of three simple shapes:

Feature type	Nature	Examples
Point	Positional: one location, no length or area	Wells, tube wells, bus stops, towns (at small scale)
Line	Linear: has length but no width at map scale	Roads, rivers, railway lines, canals
Area / polygon	Areal: a closed boundary that covers space	Lakes, districts, forests, land-use parcels

• The choice depends on scale. A city is a point on a map of India but an area on a district map.

Where spatial data comes from and why it matters

• Three sources: 1. Buy digital data from suppliers, such as Survey of India or the NRSC geoportal Bhuvan. 2. Digitise paper maps, i.e. turn them into computer form by tracing or scanning. 3. Do your own surveys with ground survey, GPS or remote sensing.

• The choice depends on the application, the budget and the data structure needed.

• Data are the backbone of GIS. Data is one of the five GIS components (hardware, software, data, people, procedures). Without good data, no analysis is possible.
• Spatial data makes GIS analysis possible:
• Overlay: stacking layers such as soil, slope and rainfall on top of each other to find land suitable for a crop.
• Buffering: drawing a zone of fixed width around a feature, for example 500 m on both sides of a river or highway.
• Joining by location code: linking Census data and health data through a shared district code.

Where it occurs

• Bhuvan (India): ISRO's geoportal, built and run by NRSC (Hyderabad), at bhuvan.nrsc.gov.in. Users can view remote sensing data and download satellite data free of cost [4].
• It runs about 150 web services that government departments use for geospatial governance (governing with the help of maps and location data) [5].

• Its modes include Standard, Thematic (natural-resource layers made with State Remote Sensing Applications Centres), Data Hub & Analytics, and Disaster Services (near-real-time alerts) [5].

• Survey of India: a government supplier of digital spatial data. It also plays a key role in carrying out the National Geospatial Policy [7].

• Remote sensing satellites: spatial data is collected from aircraft and satellites, from aerial photography to Landsat (1972) and India's IRS-1A (1988).
• GPS / GNSS: gives the exact position (latitude, longitude, height) of a point on the ground, which is how surveyors collect point data.
• Policy framework in India:
• 2021: the Government announced liberalised guidelines for acquiring and producing geospatial data and services, including maps [6].
• National Geospatial Policy (NGP) 2022: notified on 28 December 2022, with a vision running to 2035 [3]. It replaced prior approval, security clearance and licences with self-certification (users declare for themselves that they follow the rules) [2]. Geospatial data made with public funds is to be openly accessible [3].

• Operation Dronagiri was launched together with the GDI (Geospatial Data Integration platform) (2024) as a milestone under the NGP [7].

• Uses in India: urban planning, finding sites for facilities, marking flood and industrial risk zones, and land-records work.

Don't confuse with

• Attribute (non-spatial) data: describes a feature (name, price, population) but has no location of its own. Spatial data always has a coordinate-based location. A cycle shop's stock register is attribute data, while state-wise literacy is spatial.
• GIS: GIS is the system that captures, stores, analyses and displays data. Spatial data is the input it works on.
• Remote sensing: this is a method of collecting spatial data from aircraft or satellites. It is not the data itself.
• Point vs area feature: these are not fixed. The same city is a point at small scale (map of India) and an area at large scale (district map).

Prelims Hooks

• Spatial data is registered to a coordinate system. Attribute data has no location of its own.
• NCERT Box 4.1: state-wise literacy → spatial; cycle shop's stock register → non-spatial.
• Feature matches: wells, towns, bus stops → point; roads, rivers, canals → line; lakes, districts, forests → polygon (area).
• Three sources of spatial data: buying digital data, digitising paper maps, and doing your own surveys (ground, GPS, remote sensing).
• Bhuvan belongs to ISRO and is run by NRSC (Hyderabad). Its satellite data can be downloaded free [4].
• NGP 2022 was notified on 28 Dec 2022. It replaced security clearance with self-certification and opened up publicly funded geospatial data [2][3].

Mains Points

• Spatial data turns maps into planning tools (GS-I/GS-III):
• Location-linked data lets a GIS run overlay (site suitability), buffering (flood or industrial risk zones) and joins by district code (Census plus health data).

• This speeds up "what if" analysis in urban planning and disaster management.

• Policy has freed spatial data:

• The 2021 guidelines and NGP 2022 removed licences and clearances and opened up publicly funded data [2][3][6].
• Along with free platforms like Bhuvan (about 150 web services) [5], this lowers costs for start-ups, states and researchers.

• The NGP has targets for better spatial data: a DEM (Digital Elevation Model: a digital map of ground height) at 25 cm for plains and 1–3 m for hills by 2030. By 2035 it aims for bathymetry (maps of underwater depth), mapping of underground pipes and cables, and National Digital Twins of major cities [3].

• Problems that remain:

• Data standards differ between agencies, and digitised maps vary in quality.
• There are not enough trained GIS staff, so the people and procedures components stay weak.
• Because of this, actual use of spatial data lags behind what the data and the policy now allow.

Related concepts

• Database management system
• Computer assisted cartography
• Spatial information technology
• Geographic information system
• Attribute data
• Point, line and area features
• Advantages of GIS over manual maps
• Components of GIS

Read more

• Spatial information technology and GIS: concepts and components