Site Geo · GIS on live map tiles

GIS software online — plot areas on a live satellite map

Site Geo is the GIS module inside CivilOS: you open a live satellite or street map in a browser tab, click the corners of a piece of land, and immediately read its area, perimeter, every side length and every side bearing. It is written for civil engineers, architects, land buyers, PMC staff and site teams who need a defensible number for a piece of ground long before a formal survey party is mobilised — and who would rather not install a desktop GIS to get it.

Nothing is downloaded and nothing is charged. The plots you draw are stored in your own browser, and you can carry them out as GeoJSON, KML or DXF whenever you want them somewhere else.

What you can do

Feature	What it does	Export
Draw plots	Click corners on the map to close a polygon; area and perimeter update live	GeoJSON · KML · DXF
Draw routes	Polylines for a road, pipeline, boundary wall or approach, with running length	GeoJSON · KML
Labelled markers	Pin a borehole, tree, pole, gate, bench mark or photo location	GeoJSON · KML
Vertex editing	Drag a handle to move a corner; right-click a handle to delete a stray point	—
Geodesic area	Spherical-excess area on WGS-84 — correct at any latitude and any plot size	Report
Sides & bearings	Length and bearing of every side, corner-lettered A, B, C…	DXF text · Report
Setback / buffer	Offset the boundary inward (building line) or outward by a chosen number of metres	GeoJSON · DXF
Overlap of two plots	Clips one plot against another and reports the common area in m²	On screen
Centre + UTM	Centroid printed as DMS latitude/longitude and as WGS-84 UTM zone, easting, northing	Report
FAR / FSI + coverage	Permissible built-up area and maximum ground footprint from the figures you enter	Report
Basemaps	Streets (OpenStreetMap), Satellite (Esri), Terrain (OpenTopoMap), Light (Carto)	—
Coordinate calculator	Type a list of X,Y metres or lat/long pairs and get area, bearings and a plot sketch	DXF · Report
GeoJSON import	Bring a polygon you already have back onto the map	—

How it fits an Indian workflow

Almost every land question in India comes down to four numbers, and Site Geo is built around them. The plot area settles the sale and the sanction. FAR or FSI multiplied by that area gives the built-up area the development authority will permit. Ground coverage as a percentage caps the footprint you may put on the earth. And the setback — the building line measured in from each boundary — decides where that footprint can sit. Site Geo asks you for the FAR and the coverage percentage rather than guessing, because those figures come from your local development-control regulations and NBC-referenced bye-laws, which differ between a Jaipur colony, a Hyderabad municipal ward and a Kerala panchayat.

The coordinate side is equally practical. Revenue and survey departments across India work in UTM on WGS-84; the country falls in zones 42N to 47N, and the centre-point readout gives you the zone letter, easting and northing directly, alongside degrees-minutes-seconds for the record sheet. Areas are shown in square metres, acres and square feet, so a figure can be quoted in whichever unit the other party in the conversation uses. When a plot has been described to you as a bearing-and-distance schedule rather than a map, the coordinate calculator takes the typed vertex list instead and produces the same area, the same side table and the same DXF.

Once a boundary exists as DXF, it stops being a map exercise and becomes a drawing: import it into IndoCAD, set out the building line, and the site plan is under way with the real plot shape rather than a rectangle someone assumed.

How to measure a plot on a satellite map

Open Site Geo and switch the basemap to Satellite — Esri World Imagery is usually the sharpest for Indian towns.
Use the search box to jump to a place name or coordinate pair, or press my location if you are standing on the site.
Zoom in until the boundary wall, bund or kerb line is unambiguous. Accuracy is decided here, not later.
Start a Plot and click each corner in order; close the ring to finish. Area, perimeter and side lengths appear as you go.
Nudge the shape: drag a vertex handle onto the true corner, and right-click any handle you clicked by mistake to remove it.
Type your FAR / FSI and coverage % to read the permissible built-up area and the maximum footprint.
Apply an inward setback in metres to draw the building line as a second shape you can keep or export.
Export GeoJSON (other GIS), KML (Google Earth) or DXF (CAD), or print the plot report with its side-and-bearing table.

What CivilOS does not do

No shapefile support. GeoJSON goes in; GeoJSON, KML and DXF come out. A .shp file must be converted elsewhere first.
No raster or remote-sensing analysis. There are no WMS/WFS layers, no band maths, no classification, no attribute joins and no SQL querying of a spatial database.
No terrain model. Site Geo has no contours, no DEM, no spot-level surface and therefore no cut-and-fill volumes. It measures plan geometry only.
Map tiles need the internet. Your saved plots survive offline because they are stored on the device, but imagery is fetched live from public tile servers.
It is not a legal survey. Public imagery can be shifted by metres, and clicked corners are only as good as the eye behind them. Sanctioned demarcation, revenue records and a DGPS or total-station survey remain the authority for any boundary that matters.
It does not know your bye-laws. FAR, coverage and setback values are typed in by you; CivilOS does not look up or verify a municipality's development-control rules.

Where a browser GIS fits

Desktop GIS packages exist for a different scale of problem. They are used to manage many layers at once, reproject between dozens of coordinate systems, run geoprocessing chains, analyse satellite raster imagery, build terrain surfaces and produce cartographic map sheets — work that legitimately needs a full desktop application, a proper data store and someone trained in it. Civil-engineering design suites in the same family go further still, handling corridors, alignments and earthwork surfaces.

Site Geo deliberately covers a narrower job, the one that comes up constantly on live projects: how big is this piece of land, what are its sides and bearings, how much may I build on it, and can I hand that boundary to whoever needs it next? It answers that in a browser tab on a phone or laptop, with no licence and no installation, and it hands over clean interchange files so the heavier tools can take the work on. If you already run a desktop GIS, treat this as the quick field-and-meeting companion to it, not as a substitute for it.

Frequently asked questions

Is this GIS software really free?

Yes. Site Geo is part of CivilOS, which is free and runs in a browser tab with nothing to install. You can add it to a phone or desktop home screen as a PWA. Drawings stay on your device unless you choose to save them to the cloud.

How accurate is a plot area measured on a satellite map?

The arithmetic is exact: area is computed by spherical excess on the WGS-84 sphere, so it does not drift with latitude or plot size the way a flat shoelace calculation does. The accuracy you actually get depends on the imagery, which can be shifted by a few metres, and on how precisely you click the corners. Use it for planning; use the sanctioned demarcation or a DGPS survey for anything legal.

Can I export the plot to Google Earth or AutoCAD?

Yes. KML export opens in Google Earth. DXF export writes the plot outline in local metres with the side lengths labelled, so it can be traced over or dimensioned in any CAD program. GeoJSON export carries the full lat and long geometry to other GIS tools.

Does it calculate FAR, FSI and ground coverage?

Yes. Select a plot, type the FAR or FSI and the permissible coverage percentage, and you get the permissible built-up area and the maximum ground footprint in square metres. CivilOS does not know your local development-control rules, so the FAR and coverage figures you type must come from your sanctioned bye-laws.

Can I draw a setback or building line?

Yes. Choose an inward offset in metres and the plot ring is offset along its angle bisectors to give the building line. If the setback is larger than the plot can take, the tool says so instead of drawing a ring that has turned inside out.

Does the map work offline?

Partly. CivilOS installs as a PWA and your plots, FAR settings and coordinate lists are stored on the device, so they survive a reload. The basemap tiles are fetched from OpenStreetMap, Esri, OpenTopoMap or Carto, so a live internet connection is needed to see fresh imagery.

Can I import a shapefile?

No. Site Geo imports GeoJSON only. If you have a .shp file, convert it to GeoJSON in a desktop GIS first, then import it here.

Open Site Geo free → draw a plot, read the area, export GeoJSON · KML · DXF

Planning figures, not a survey. Areas taken off public imagery are for study and estimation. For registration, demarcation disputes or sanction drawings, rely on the approved survey record and have a licensed surveyor or engineer certify the boundary.