Quick Answer
How do you shoot elevations with a digital level?
Set up the digital level, level the circular bubble, aim at the bar-code rod, and press Measure. The level reads the rod bar code automatically and displays the rod reading and distance to the rod. Use the HI method — backsight on a known benchmark to get HI, then foresight on each elevation point. Data records automatically in the onboard memory.
How to Shoot Elevations with a Digital Level
Applies to: Topcon DL-501/DL-503, Leica Sprinter 150M, Trimble DiNi 0.3, Sokkia SDL30M
Digital levels replace the traditional process of reading a rod graduation through an eyepiece with an electronic bar-code scanning system. Aim the telescope at the bar-code rod, press a button, and the instrument displays the rod reading and the distance — no estimation, no reading errors, no transcription errors in the field book. For crews running benchmark leveling, as-built floor surveys, or any work requiring precise elevation documentation, digital levels are faster and more reliable than optical levels. This guide covers the complete workflow from setup through data export.
Step 1: Set Up and Level the Instrument
Set the digital level on a tripod between the benchmark and the first rod position. Extend the tripod legs to a comfortable working height and set them firmly. Unlike optical levels, digital levels have no user-adjustable tilting screw — they rely entirely on the automatic compensator. Level the circular bubble using the footscrews until it is centered. The compensator then maintains a horizontal line of sight automatically within its compensation range (typically plus or minus 12-15 arc minutes, wider than most optical levels).
Power on the level and allow the electronics to initialize — most Topcon and Leica digital levels initialize in under 10 seconds. On the display, confirm the compensator status shows normal (not a tilt warning). Create a new job or survey file to store the session's measurements.
Step 2: Configure the Job Settings
Enter the project benchmark elevation into the level's job settings before shooting. On the Topcon DL-501, navigate to Job > New > Input BM. On the Leica Sprinter, select Function > BM Setup. On the Trimble DiNi, configure the starting benchmark in the leveling program. Entering the benchmark elevation into the instrument allows it to compute and display elevations at all subsequent shots automatically without hand calculation.
Also confirm the rod type setting matches the rod you are using. Digital levels read specific bar-code patterns printed on invar or fiberglass rods. The instrument must know whether it is reading a metric-coded rod (e.g., Leica-format) or a feet-coded rod (Topcon/Sokkia format). Using the wrong rod type causes completely wrong readings — the numbers look plausible but are systematically offset.
Step 3: Read the Opening Backsight
Hold the bar-code rod plumb on the benchmark. Sight the telescope at the rod and press the Measure button. The level scans the bar code, computes the rod reading, calculates the distance, and displays the Height of Instrument (HI = benchmark elevation + rod reading). On most models, this is displayed automatically once you have set the benchmark elevation. Record the HI and the distance to the rod.
The displayed distance (from instrument to rod) is useful for quality control — short sight distances (under 5 feet) can cause reading errors on some digital levels because the bar-code is too close to resolve properly. Most instruments have a minimum distance of 1.5-3 meters (5-10 feet). Similarly, very long sight distances (over the instrument's rated range, typically 100-160 meters or 300-500 feet) degrade reading reliability in anything other than ideal conditions.
Step 4: Shoot Foresight Elevations
Walk to each elevation point and hold the rod plumb. Aim the instrument and press Measure. The display shows the rod reading, the computed elevation (HI - rod reading), and the distance. The measurement is recorded in the job file automatically on most digital levels — no transcription required. On instruments like the Topcon DL-501, a confirmation shot (two rapid successive readings that agree within a set tolerance) can be required before the elevation is accepted, reducing gross blunder errors.
For floor elevation surveys, slab checks, and as-built surveys, this workflow is dramatically faster than optical leveling. A single operator can shoot 50-100 elevation points per hour with a digital level vs. 20-30 with an optical level and manual recording. The rod can be held by the operator working alone using a rod holder or bipod on flat surfaces.
Step 5: Export the Elevation Data
At the end of the session, export the recorded elevation data from the instrument. Most digital levels support export via internal memory download (USB or RS-232 cable) or SD card. Export formats include plain text, CSV, and manufacturer-specific job formats. On the Leica Sprinter 150M, use the Leica Geo Office software for download. On the Topcon DL series, use TopSURV or export directly to CSV. Import into a spreadsheet, CAD program, or field documentation platform for as-built comparison against design elevations.
Back up the raw job file from the instrument to a computer before clearing the memory for the next session. Digital level job files are small and easy to store, but data lost because the memory was cleared without backing up cannot be recovered.
Frequently Asked Questions
How accurate is a digital level compared to an optical level?
High-precision digital levels like the Trimble DiNi 0.3 achieve 0.3mm per kilometer standard deviation — significantly better than most optical levels. Standard construction digital levels (Leica Sprinter 150M, Topcon DL-501) achieve 1.5-2.0mm per kilometer, roughly comparable to a quality optical automatic level. The accuracy advantage of digital levels is primarily in eliminating reading errors and transcription errors, not in the physical measurement.
Can I use any rod with a digital level?
No. Digital levels require a bar-code graduated rod matched to the instrument's reading system. The Leica Sprinter reads Leica-format bar-code rods. Topcon and Sokkia digital levels read their own bar-code format. Trimble DiNi reads Trimble/Zeiss format. Most rods also have conventional graduation on the reverse side for use with optical levels.
What happens if the digital level cannot read the rod?
Common causes of reading failure: the rod is too close or too far from the instrument, the bar-code face is dirty or damaged, the rod is tilted significantly off vertical, or the lighting is either too bright (direct sunlight washing out the bar code) or too dark. Shade the bar-code surface in direct sunlight, clean the rod, and ensure the rod is held within the instrument's rated distance range.
Do I still need to balance sight distances on a digital level?
Yes. Balancing backsight and foresight distances is still good practice even on digital levels. Digital levels compensate electronically for the compensator error but still benefit from balanced sights in precision leveling. Most digital levels display the cumulative sight distance imbalance and warn when it exceeds a set threshold.
Import digital level elevation data directly into Gradelog for automated as-built floor surveys, benchmark documentation, and elevation report generation. Free to start at gradelog.com.
