Point, line and polygon in field mapping
Most mapping and GIS work starts with points, lines and polygons.
Field takeaways
- A point represents one location.
- A line represents length and route.
- A polygon represents a closed area.
- Wrong geometry type creates area and export confusion.
- MapLab Survey collects all three as layers.
Three geometries, three questions
A point marks a location, a line measures a length and a polygon measures an area. Choosing the wrong one at capture time means recapturing later, because you cannot reliably turn a track into a boundary. The choice is made by one question: what will I ask of this data afterwards?
When a point
Use a point for a single location: a parcel corner, a power pole, a valve, a manhole, a sampling spot, a photo position, a stake-out peg. Its name, coordinate, note and photo must be unambiguous — and the code, date and image attach to the feature itself, not to a separate notebook.
When a line
Use a line for a route or a length: a road edge, a pipe run, a stream, a fence, a walked route, an excavation edge. Where you place the break points directly affects the length; put them where the line turns, not at fixed intervals.
When a polygon
A closed area needs a polygon: a parcel, a field, a stockyard, an earthworks footprint, a safety zone, a project boundary. Area and perimeter are computed from the polygon, and one that does not close gets both wrong.
Layers and export
Keeping points, lines and polygons on separate layers pays off at the office. Names like "existing_pole", "design_line" and "measured_parcel" preserve the file's meaning. Decide the destination before you start: CAD wants lines and polygons on clean layers, a GIS wants attributes with the geometry — and the KML, DXF and GeoJSON exports come out clean accordingly.
See it in action
MapLab Survey | Professional Mobile GIS, GPS Surveying & Land Measurement App
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MapLab Survey handles RTK/GNSS point capture, drawing, area and volume calculations and coordinate conversion, then exports to DXF, KML/KMZ, GeoJSON, Shapefile, GeoPackage, NCZ or CSV. Capture, calculation and export work offline. Live NTRIP corrections and online basemaps need a connection.
Frequently asked questions
What is a polygon?
A closed area geometry.
Line or polygon?
Line is a path, polygon is an area.
When is point used?
For single-location features.
Does MapLab Survey support them?
Yes.
Technical references
The field guidance in this article is aligned with the technical and official references below.
Related: Area measurement app · Measure map distance · Exporting field data to CAD/GIS · MapLab Survey