KML and KMZ Viewer for Tender Drawings
The file is unzipped and parsed in this browser and is never uploaded. Turning the base map on is the only thing here that makes a network request: map tiles are fetched from OpenStreetMap, which means the area you are looking at is visible to them. Leave it off and the geometry is drawn on a grid with a scale bar instead.
Everything here is computed in your browser. Nothing you type is sent to a server, stored, or logged. Figures shown as defaults are starting points, not fixed rates: read the actual percentages from your notice or contract.
How this is worked out
A KMZ is an ordinary zip archive with a KML inside it. Both are unpacked here, in the browser, using the decompression the browser already ships with. There is no upload step, which matters when the attachment came out of a tender document you are under an obligation not to circulate.
The viewer reads points, lines, rings and polygons out of every placemark and draws them, then reports the count, the bounding box and the total path length. Length is computed as great-circle distance between consecutive coordinates, which is the figure that matters for a route and is close enough at tender-estimate precision.
The base map is a switch, and it is off until you turn it on. With it off nothing is fetched and the geometry is drawn on a grid with a scale bar. With it on, map tiles come from OpenStreetMap, which means the area you are looking at becomes visible to them, so that is a choice you make rather than one made for you.
Export to GeoJSON is there because most estimating and GIS tools read GeoJSON more comfortably than KML, and because a route you can load into your own software is a route you can actually work with.
Frequently asked questions
How do I open a KMZ file without Google Earth?
Drop it on this page. A KMZ is a zipped KML, and both are unpacked and drawn in your browser, so you do not need Google Earth, an account or a desktop install. You get the geometry, the total length, the bounding box and a GeoJSON export.
Is my file uploaded anywhere?
No. The archive is unzipped and the XML parsed by your own browser, and nothing is transmitted. The one exception is the base map, which is off by default: turning it on fetches map tiles from OpenStreetMap, which reveals the area being viewed to them but never the file. Leave it off if that matters for the attachment you are opening.
Why do road and canal tenders attach a KML?
Because the alignment decides the cost and the notice cannot describe it in prose. The KML tells you the length, the terrain it crosses, how far it sits from your nearest plant and quarry, and how much of it is in built-up land where working hours are restricted. A bidder who prices the BOQ without opening the alignment is pricing a route they have not seen.
The length shown does not match the tender document. Why?
Chainage in a tender is measured along the design centreline with curves and gradients, while this measures great-circle distance between the coordinates the file actually contains. A file recorded at coarse intervals will read shorter than the chainage. Treat this as a check on the order of magnitude and the corridor, and take the schedule quantities from the document.