Opening field data on a computer: from phone to desk with KML, DXF and Shapefile
The measuring ends in the field, but the job is usually finished at a desk.
Field takeaways
- The format decides what travels: geometry, attributes, layers or the coordinate system.
- KML and GeoJSON always carry WGS84 geographic coordinates.
- A Shapefile's coordinate system lives in its .prj file; always put it in the zip.
- DXF and CSV carry no system information; you have to choose it when importing.
- After import, check the count, one length and one known point.
Why a computer?
In the field the phone has no rival: it is in your hand, it takes a position, it takes a photo. But printing a map sheet, typing in coordinates, editing a long attribute table or comparing the drawing with a CAD file is faster on a big screen. When you move the data to the desk, the aim is to lose nothing you measured on the way, and that starts with choosing the right format.
Each format carries something different
KML and KMZ carry geometry, names and folders; they work with Google Earth but are weak for long attribute tables. GeoJSON carries geometry together with complete attributes and is the common language of web maps. Shapefile carries the attribute table and the coordinate system (.prj); the .shp, .shx, .dbf and .prj files must travel together, most easily in a single zip. Field names are limited to 10 characters, so long column names get cut. DXF carries layers and the drawing and is the right choice for work going to CAD. CSV is for point lists: name, X, Y, Z.
Where is the coordinate system written?
By standard, KML and GeoJSON use WGS84 geographic coordinates, that is longitude and latitude, so there is no ambiguity there. In a Shapefile the system lives in the .prj file; without it the data may look fine on screen but will not sit in place. DXF and CSV carry no system information at all, only numbers. When you open them you have to choose the source system yourself; in Türkiye that is usually a TM zone based on ITRF96 or ED50. In those zones the easting (Y) has six digits and the northing (X) seven, a difference that immediately gives away swapped columns.
Three checks after import
Once the file is open, look at three things. First the count: as many points and areas on screen as you measured in the field. Second a length or an area: an edge or parcel area you know from the field should come out the same on the computer. Third a known point: a boundary stone or a building corner should sit where it belongs on the base map. If one of these three fails, the cause is almost always the coordinate system or the column order.
Keep the original, back up the workspace
Do not delete the export you took from the phone; every change you make on the computer is made on a copy of it, and it is the only place you can go back to when something goes wrong. Browser-based tools often keep your data in the browser itself; if the browser data is cleared, the workspace goes with it. Export your work regularly or back it up as a package; in MapLab Survey Web that package is the .mlsw file.
Open your field data in the browser.
MapLab Survey Web opens KML/KMZ, DXF, Shapefile, GeoJSON, CSV and total-station files (GSI, RW5, SDR, Nikon, LandXML) in the browser. It never guesses the coordinate system silently; it asks you to confirm the datum and zone. Drawing, measuring, import and export work without signing in. Interface in Turkish and English.
Frequently asked questions
What is the easiest way to move a phone project to a computer?
Export it from MapLab Survey as KML/KMZ, GeoJSON, Shapefile, DXF or CSV and open it on the computer. If the attributes matter, choose GeoJSON or Shapefile.
Why do the coordinates in a KML show as degrees?
By standard, KML uses WGS84 longitude and latitude. If you need projected coordinates, convert to the system you want after opening.
The Shapefile opens but sits in the wrong place. Why?
Most likely the .prj file is missing or wrong. Check whether the zip contains a .prj; if not, choose the source system by hand.
Which coordinate system should I open a DXF in?
The one the drawing was made in. DXF does not say; ask whoever prepared it or verify against a known point.
Technical references
The field guidance in this article is aligned with the technical and official references below.
Related: Exporting field data to CAD/GIS · Open DXF on phone · ED50 to TUREF · MapLab Survey