Quick Answer
QGIS is a full-featured GIS platform that handles heritage site management, spatial analysis, condition mapping, orthophoto display, survey data integration and publication-ready map production at no software cost. Key workflows: design a GeoPackage database with attribute tables for building elements, condition grades and heritage significance; import drone orthophotos and TLS/photogrammetry point clouds; digitise building footprints and condition zones; run spatial analysis (buffer zones, visibility analysis, spatial queries); export heritage maps to PDF/SVG for reports.
Most Indian heritage organisations — INTACH chapters, state archaeology departments, temple trusts, conservation architects — operate under budget constraints that rule out the ₹5–15 lakh annual software subscription of ArcGIS or similar commercial GIS platforms. QGIS solves this problem: it is free, fully open-source, runs on Windows, Mac and Linux, and is capable of everything a professional heritage GIS project requires.
QGIS has been adopted as the GIS standard by many Indian archaeology departments and is the platform of choice for INTACH's heritage mapping projects. Its plugin ecosystem includes QGIS2Web (publish maps as interactive web applications), QField (field data collection on mobile), and numerous archaeology-specific tools.
This guide covers the practical workflows specific to heritage site management: database design, data import, condition mapping, spatial analysis and professional map production.
Why QGIS for Heritage Work
QGIS vs ArcGIS for heritage documentation
| Factor | QGIS | ArcGIS Pro |
|---|---|---|
| Software cost | Free and open-source | ₹5–15 lakhs/year subscription (ArcGIS Online + Pro) |
| GeoPackage / SQLite support | Native — recommended format | Supported but ESRI formats preferred |
| Plugin ecosystem | 1,000+ plugins including archaeology-specific tools | Limited; ESRI ArcToolbox is comprehensive but proprietary |
| Field data collection | QField (free) — same project files | ArcGIS Field Maps (subscription required) |
| Web mapping | QGIS2Web plugin (free); Leaflet output | ArcGIS Online (subscription) |
| Heritage-specific extensions | QGIS Archaeology plugin, QChainage, historical maps | Some via ArcGIS Marketplace |
| Interoperability | Reads/writes all major formats: Shapefile, GeoPackage, GeoJSON, KML, CAD, PostGIS, WMS/WFS | Good interoperability; some ESRI-only formats |
| Indian government adoption | Widely used in state archaeology departments; ISRO data directly compatible | Used in some NRSC/ISRO projects; Survey of India prefers QGIS or standalone GIS |
Heritage GIS Database Design
For heritage site management, a well-designed GeoPackage database is the core of the QGIS project. GeoPackage (GPKG) is an open standard SQLite container that stores both vector layers and attribute tables — suitable for long-term archiving and transfer without software dependencies.
A standard heritage site GIS database should include:
Standard layer structure for heritage site GIS database
| Layer name | Geometry type | Key attributes | Purpose |
|---|---|---|---|
| site_boundary | Polygon | site_name, legal_ref, area_sqm, protection_status | Overall site extent; heritage protection boundary |
| buildings | Polygon | building_id, name, date_of_construction, style, significance_grade (1–5), original_use, current_use | Individual building footprints with heritage attributes |
| heritage_zones | Polygon | zone_type (core/buffer/setting), authority, regulation_ref | AMASR Act zones; local heritage zones; visual catchment areas |
| condition_areas | Polygon | element_ref, defect_type, severity (1–5), date_surveyed, surveyor | Condition mapping zones overlaid on building fabric |
| survey_points | Point | point_id, description, gps_accuracy, date, survey_method | Survey control points, GCPs, TLS scan positions, GPS observations |
| photographs | Point | photo_id, filename, direction, date, element_ref, condition_ref | Photo locations — click to view image in QGIS |
| infrastructure | Line/Polygon | type (drainage, water, electricity), condition, date_installed | Service infrastructure relevant to conservation |
| vegetation | Polygon | species, dbh, condition, significance (neutral/beneficial/damaging) | Trees and significant vegetation |
Use GeoPackage, not Shapefile
Shapefile is the legacy GIS format still widely used in India. It has significant limitations for heritage work: attribute field names are limited to 10 characters (truncating 'significance_grade' to 'significan'), text fields are limited to 254 characters, and each layer requires multiple files (.shp, .dbf, .prj, .shx). GeoPackage stores everything in a single .gpkg file, supports long field names, handles Unicode (including Tamil/Kannada script), and is the recommended archival format. Start new heritage GIS projects in GeoPackage.
Importing Survey Data
Heritage GIS projects consolidate data from multiple survey sources. QGIS handles all common formats directly, with some requiring simple pre-processing.
- Drone orthophotos (GeoTIFF) — drag and drop into QGIS; the CRS is read from the GeoTIFF; set it as the background raster layer for digitising building footprints and condition areas over the top.
- Point clouds (LAS/LAZ/E57) — QGIS 3.18+ supports point cloud display natively (the Point Cloud layer type); for older versions, use CloudCompare to convert to a DEM raster or thin point cloud in LAS format.
- GPS survey data (CSV with Lat/Long) — Layer > Add Layer > Add Delimited Text Layer; specify the X and Y coordinate fields; set CRS to WGS84 (EPSG:4326) for GPS data; reproject to project CRS if needed.
- Total station data (CSV with Easting/Northing) — same as GPS import; set the CRS to the survey's coordinate system (UTM Zone or local).
- CAD drawings (DXF/DWG) — Layer > Add Layer > Add Vector Layer; select the DXF file; QGIS imports DXF layers as separate vector layers by entity type (lines, polylines, points); reproject if the DXF has embedded coordinate information.
- Google Earth KML/KMZ — Layer > Add Layer > Add Vector Layer; QGIS reads KML natively; coordinates are in WGS84.
- QGIS WMS layers (web map service) — connect to Survey of India WMS, ISRO Bhuvan, OpenStreetMap or ESRI basemaps as background reference layers (Layer > Add Layer > Add WMS/WMTS Layer).
Digitising Heritage Features
Digitising — drawing vector features over a reference raster (orthophoto, scanned map, satellite image) — is the core workflow for building the heritage GIS feature layers.
- 1Set project CRS — before starting any digitising, set the project's coordinate reference system (Project > Properties > CRS); for Indian heritage projects, WGS 84 / UTM Zone 44N (EPSG:32644) covers most of South India; check the correct zone for your project location.
- 2Load background orthophoto — add the drone orthophoto as a raster layer; it provides the base for accurate digitising of building footprints.
- 3Create new GeoPackage layer — Layer > Create Layer > New GeoPackage Layer; specify geometry type (Polygon for buildings), CRS (same as project), and add attribute fields; save to the project GeoPackage.
- 4Enable editing — select the new layer; click the pencil icon (Toggle Editing); choose the polygon digitising tool.
- 5Digitise building footprints — trace the outer wall line of each building by clicking to place vertices; right-click to close the polygon; the feature is added to the layer.
- 6Add attributes — for each digitised polygon, click the feature to open the attribute form; complete heritage attributes (building name, date, significance grade, condition).
- 7Use snapping — enable snapping (Project > Snapping Options) to ensure that adjacent building polygons share exact boundaries without gaps or overlaps.
- 8Save edits — regularly save edits during digitising; auto-save interval can be set in QGIS preferences.
Condition and Significance Mapping
Condition mapping in QGIS overlays condition assessment data (defect type, severity, cause) onto the building fabric geometry. The most effective workflow uses the drone orthophoto as the base, digitises condition zones as polygons over the facade, and symbology to display condition grades as a colour-coded overlay.
To apply condition symbology in QGIS: open Layer Properties > Symbology; select Categorised renderer; choose 'condition_grade' as the Value field; click Classify to auto-generate categories; change colours to the condition grade scale; apply.
For significance mapping, create a separate significance_zones polygon layer and apply a significance scale symbology (Outstanding / High / Moderate / Low / None, following INTACH grading or the Burra Charter framework).
QGIS symbology settings for condition mapping
| Condition grade | Suggested colour (RGB) | Description | Burra Charter / INTACH equivalent |
|---|---|---|---|
| Grade A — Good | 70, 200, 70 (green) | Sound fabric; no significant defects | Conservation maintenance only |
| Grade B — Fair | 200, 200, 70 (yellow) | Minor defects; surface deterioration only | Minor repair and maintenance |
| Grade C — Poor | 255, 165, 0 (orange) | Moderate deterioration; some structural concern | Significant repair required |
| Grade D — Very Poor | 200, 70, 70 (red) | Significant deterioration; structural instability | Urgent intervention required |
| Grade E — Critical | 130, 0, 0 (dark red) | Risk of collapse or irreversible loss | Emergency stabilisation required |
Spatial Analysis for Heritage
QGIS spatial analysis tools address specific heritage management questions.
QGIS spatial analysis tools for heritage management
| Analysis task | QGIS tool | Heritage application |
|---|---|---|
| Buffer zone mapping | Vector > Geoprocessing > Buffer | Generate the AMASR Act 100m prohibited zone and 300m regulated zone around monument boundary; overlay with development proposals |
| Visibility analysis (viewshed) | Raster > Analysis > Viewshed (from DEM) | Identify areas from which a heritage monument's silhouette is visible; assess visual impact of proposed developments |
| Area calculation | Field Calculator > $area | Calculate floor area of buildings, extent of condition zones, area of significance categories for conservation management plan reporting |
| Spatial query | Select Features by Expression | Find all buildings with condition grade D or E within 50m of a proposed access road; find all Grade A significance buildings currently in Poor condition |
| Proximity analysis | Vector > Analysis > Distance Matrix | Calculate distances from each building to nearest drainage; identify buildings most vulnerable to rising damp from high water table zones |
| Heatmap / density | Raster > Heatmap | Show concentration of defect survey points; identify areas of highest deterioration intensity on a large site |
| Change detection | Raster > Calculator (subtract two orthophotos) | Detect changed areas between two survey orthophotos — identifies new collapse, vegetation growth, or repair works between surveys |
Map Production and Export
QGIS's Print Layout (Project > New Print Layout) produces publication-ready heritage maps for conservation reports, planning applications and heritage management plans.
- 1Create a new print layout — name it by purpose (e.g. 'Site Condition Map — July 2026'); set page size and orientation.
- 2Add map frame — drag a map frame onto the layout; link it to the main QGIS map canvas; set the scale (e.g. 1:500 for a temple complex site map).
- 3Add supporting elements — north arrow (Add > Add North Arrow); scale bar (Add > Add Scale Bar); legend (Add > Add Legend — QGIS auto-generates from visible layers); title and subtitle text boxes.
- 4Add inset maps — for a site location map (showing the region), add a second linked map frame at small scale with a reference indicator.
- 5Add condition/significance table — use Add Attribute Table to display key building data alongside the map.
- 6Export — Layout > Export as PDF (for reports) or Export as SVG (for editing in Inkscape or Illustrator); Export as Image (PNG/TIFF) for inclusion in Word or InDesign documents.
QGIS Atlas for condition report sheets
QGIS Atlas generates a series of map sheets automatically — one per feature in a selected layer. For a temple complex with 20 buildings, set up an Atlas driven by the buildings layer; QGIS automatically generates 20 condition map sheets, each centred on a different building, with the building's attributes displayed in a text frame. This replaces 20 hours of manual map sheet production with a single Atlas setup.
India-Specific Data Sources
Free GIS data sources for Indian heritage projects in QGIS
| Data source | Access | Resolution / scale | Heritage use |
|---|---|---|---|
| ISRO Bhuvan satellite imagery | bhuvan.nrsc.gov.in — WMS / download | 2.5m (Resourcesat-2); 0.5m (select areas) | Background imagery; site overview maps; change detection |
| Survey of India topographic maps (SoI) | surveymaps.in — purchase; some free via Bhuvan | 1:50,000 and 1:250,000 | Site location; transport networks; benchmark positions |
| OpenStreetMap | QGIS QuickMapServices plugin — free | Varies; good in urban areas | Background mapping; street networks; site context |
| CGWB groundwater data | cgwb.gov.in — download | District-level | Groundwater table proximity — relevant to rising damp assessment |
| NRSC Archaeological Zone Mapping (Digital India Initiative) | nrsc.gov.in — project-specific | Varies | Heritage zone boundaries for some protected sites |
| India WRIS river basin data | indiawris.gov.in | River catchment level | Flood risk; drainage context for coastal and riverside heritage sites |
| Google Satellite via QGIS XYZ tiles | Add XYZ Tile connection in QGIS | Variable — good in most urban India | High-resolution background imagery; recent condition check |
Common Mistakes
- Using Shapefile instead of GeoPackage — field name truncation, multi-file complexity and 254-character text limits cause data loss and confusion; start all new projects in GeoPackage.
- Not setting a project CRS before digitising — digitising in WGS84 Geographic when the orthophoto is in UTM produces tiny geometries (coordinates in degrees instead of metres); set project CRS to match the orthophoto CRS before placing the first vertex.
- Mixing coordinate systems across layers — some layers in WGS84, some in UTM, some in local site coordinates; QGIS will reproject layers for display but calculations (area, distance, buffer) require consistent CRS; set all layers to the same CRS before running analysis.
- Saving condition data only in the map symbology, not in the attribute table — condition grades stored only as colours in the symbology are lost if the project is reopened by someone else; always store condition grades as attribute field values.
- Not backing up the GeoPackage — the entire heritage GIS database is in a single .gpkg file; a single corrupted file loses everything; backup daily to at least two locations.
Professional Practice
In professional practice, QGIS is most effectively set up as a shared project file stored on a network drive or cloud folder (QGIS 3.10+ supports cloud storage of project files via S3 or similar). This allows multiple team members — the surveyor adding GPS data, the conservation architect digitising condition zones, the report writer producing map outputs — to work in the same GIS project.
QField, the free QGIS companion app for Android and iOS, allows field data collection directly into the project's GeoPackage on a tablet, which is then synced back to the desktop QGIS project. This replaces paper condition survey forms with structured digital data collection directly tied to the heritage GIS database.
For professional map outputs from QGIS, the Print Layout is capable but has a learning curve for producing heritage-quality cartography. Consider exporting base maps as georeferenced PDFs from QGIS and completing final cartography in Inkscape (free) or Adobe Illustrator if publication-quality typography and design is required.
Key Takeaways
- 1QGIS is a fully professional GIS platform suitable for all heritage site management workflows, at zero software cost — the only practical choice for budget-constrained heritage organisations in India.
- 2GeoPackage (.gpkg) is the correct database format for heritage GIS projects — it stores all layers in a single portable file, supports long field names and Unicode text, and is an open archival standard.
- 3Condition mapping in QGIS combines digitised condition polygon layers, colour-coded symbology (green/yellow/orange/red/dark red by grade), and attribute tables storing structured condition data — replacing paper condition forms with spatially located, queryable heritage data.
- 4The AMASR Act buffer zone analysis (100m/300m from monument boundary) is a standard spatial analysis task in QGIS — run the Buffer tool on the monument boundary layer and overlay with proposed development footprints.
- 5QField enables field data collection directly into the QGIS GeoPackage on a mobile device, eliminating paper condition survey forms and manual data transcription.
Frequently Asked Questions
Is QGIS suitable for professional heritage GIS, or is ArcGIS required?
QGIS is fully suitable for professional heritage GIS, including all workflows required for conservation management plans, heritage impact assessments, condition mapping and spatial analysis. Many INTACH chapters and state archaeology departments use QGIS as their primary GIS platform. The only scenarios where ArcGIS is specifically required are: client specifications that mandate ArcGIS deliverables in proprietary formats (.gdb, .mxd), or projects requiring ArcGIS-specific extensions (some ESRI spatial analysis tools not yet replicated in QGIS). For most Indian heritage projects, QGIS is the practical choice.
What coordinate system should I use for a heritage GIS project in Tamil Nadu?
For most heritage GIS work in Tamil Nadu, WGS 84 / UTM Zone 44N (EPSG:32644) is the recommended coordinate system — it provides metre-based coordinates accurate for distance and area calculations across the state. For projects that need to integrate with national Survey of India data, the SOI datum is technically the Indian 1975 / UTM projection but most modern Indian survey data (Bhuvan, GPS) uses WGS84. Set the project CRS to EPSG:32644 and reproject any legacy data from other CRS on import.
Can QGIS display drone orthophotos produced in Agisoft Metashape?
Yes. Export the Metashape orthophoto as GeoTIFF with the coordinate system and world file; load it directly into QGIS as a raster layer. The CRS is embedded in the GeoTIFF and QGIS reads it automatically. For large orthophotos (>500MB), generate an overview (Raster > Miscellaneous > Build Overviews) to improve display performance. The orthophoto can then serve as the base layer for digitising building footprints, condition zones and significant elements.
Further Reading
Jabendra Raja
Technical-Commercial Partner, Evergreen Origins
Jabendra Raja leads spatial analysis and GIS practice at Evergreen Origins, with QGIS-based heritage GIS work across Tamil Nadu temple surveys, condition mapping projects and conservation management plan data management.