The procurement-checklist articles cover what to put in the brief. This is the inverse — what the operator does when a brief is silent. Every project brief omits something; the operator's quote reflects their interpretation of the omission. The interpretations are usually defensible, often well-intentioned, and sometimes wildly different between operators. The same brief sent to three operators producing three different prices isn't necessarily about competitive pricing — it's about three different reads of the gaps.
If you've ever sent the same procurement brief to three drone LiDAR operators and received three quotes that varied by 40-60% without any obvious explanation, you've met the brief-interpretation problem. The quotes are responding to the same document — but they're responding to three different interpretations of that document. Each operator filled the gaps with their own defaults; the gaps were big enough to produce materially different cost structures.
The fix isn't to write a longer brief (briefs that specify everything get ignored or produce defensive responses). The fix is to know which items operators fill in by default and to spot-check the interpretation on the items that matter for your project. The procurement checklist article covers the six highest-leverage items to specify explicitly; this article covers the broader inventory of twelve items operators default on, with the typical default for each.
This is the buyer-side companion to the operator's mental model. Reading what's not in your own brief gives you the same lens the operator uses when reading it.
Three structural reasons the same gap gets filled differently by different operators:
1. Local-market default has set in. Operators working primarily in one region (Sydney metro, Pilbara mining, Tasmania forestry) develop defaults that reflect their typical client base. The Pilbara operator's default is mining-grade; the suburban Sydney operator's default is planning-grade.
2. Sensor and processing pipeline drive interpretation. An operator with a high-density sensor defaults to higher density; an operator with a mid-tier sensor defaults to lower. The brief that doesn't specify density gets the answer the operator's kit naturally produces.
3. Risk tolerance varies. Some operators interpret ambiguity conservatively (assume buyer wants better spec, quote higher); others interpret aggressively (assume buyer wants cheaper, quote lower). Both can be right; the buyer doesn't see the underlying choice.
(See reading a capture proposal article for the proposal-side companion to this brief-side piece.)
What gets defaulted. If the brief says "high accuracy" without a number, operators fill in based on what their kit and processing typically produce.
Typical defaults. Mid-tier operators default to ~±50 mm RMSE; higher-tier default to ±20-30 mm; planning-focused default to ±100 mm or looser.
Why it matters. Two operators quoting the same brief at ±50 mm and ±20 mm aren't competing on the same scope. The price gap reflects different work.
Test question. "What RMSE accuracy do you commit to at independent control checkpoints?"
(See accuracy article for the underlying spec considerations.)
What gets defaulted. Density spec rarely appears in briefs at the operator-specified level. The default is whatever the operator's preferred flight altitude and speed produce.
Typical defaults. 30-80 ppm² for engineering- grade captures; 15-30 ppm² for planning-grade; 100+ ppm² only when specifically requested.
Test question. "What's your committed minimum density across the project, and what stratification will the QA pack report?"
(See PRR vs density article for the density-vs-sensor-spec context.)
What gets defaulted. GDA2020 horizontal + MGA Zone matching the project location + AHD vertical. Standard Australian convention.
Typical exceptions. Legacy projects that specifically work in GDA94. Mine sites with local grids. International clients defaulting to WGS84.
Test question. "Confirm horizontal datum (GDA2020 or GDA94), MGA Zone, and vertical datum (AHD or ellipsoidal). Will EPSG codes be encoded in deliverables?"
(See coordinate transformations article for what happens when this defaults wrong.)
What gets defaulted. ASPRS standard classes (ground, low/medium/high vegetation, building, water). Some operators stop at ground extraction and call the rest "unclassified".
Typical defaults. Basic ASPRS subset (classes 1, 2, 3-5, 6, 9) for engineering work. Extended classes (powerlines, transmission towers, road surface) only when specifically requested.
Test question. "What ASPRS classes will be populated, and what's the precision/recall target for each?"
(See ground classification article for the underlying classification mechanics.)
What gets defaulted. Operators typically default to flying the AOI boundary with minor (10-30 m) incidental overflight for swath coverage. No explicit buffer planning unless requested.
Typical defaults. "Capture covers AOI" is the common interpretation; deliverable boundary equals captured boundary.
Test question. "Will the captured area extend beyond the deliverable boundary, and by how much?"
(See edge effects article for the structural buffer calculus.)
What gets defaulted. Operators default to their own preferred format combinations — typically LAS 1.4 LAZ for point cloud, GeoTIFF for raster, DXF or shapefile for vector, PDF for reports.
Typical defaults vary by operator's typical consumer base. Mining-focused defaults differ from civil-focused defaults differ from GIS-focused defaults.
Test question. "What specific file formats and versions, tile structure, naming convention, and manifest format will the deliverable include?"
(See LAS/LAZ article for the format landscape.)
What gets defaulted. Some operators ship a full 10-section QA pack by default; others ship "accuracy achieved: ±X mm" and a tile listing.
Typical defaults. Mature operators default to comprehensive; less mature default to minimal.
Test question. "What sections will the QA pack contain, and will it be signed off by an independent reviewer?"
(See QA report article for the 10-section convention.)
What gets defaulted. Often nothing. Many operators retain whatever they happen to retain without a documented policy. Some purge at delivery.
Typical defaults. 3-6 months retention is common; 12+ months is mature; indefinite is rare.
Test question. "What's your archive retention policy for raw source data, and is there a reprocess pricing schedule?"
(See re-fly decisions article for what the archive specifically enables.)
What gets defaulted. Software versions, classification parameters and manual edits often aren't documented in the deliverable unless specifically requested.
Typical defaults. Mature operators document by default; less mature don't.
Test question. "Will the processing chain (software versions, parameter values, manual edits) be documented in the deliverable?"
What gets defaulted. Day-rate mobilisation ($1,500-3,500/day) is the typical structure. Some operators bundle mobilisation into per-hectare pricing; some charge separately.
Typical defaults. Separate mobilisation line is the convention. What the day actually covers varies between operators.
Test question. "How is mobilisation priced, and what's included in the day rate? What happens if a mobilised day is weathered out?"
(See mobilisation costs article for the cost-stack walk-through.)
What gets defaulted. Operators carry implicit contingency for weather, technical issues and scope adjustments. The contingency might be 5%, might be 25%, depending on operator and project specifics.
Typical defaults. Conservative operators carry more; aggressive ones carry less. Not visible in the quote line items.
Test question. "What's your typical no-go rate for this project type, and how is contingency priced?"
What gets defaulted. Net-30 from invoice is the typical Australian default. Some operators require deposit (10-30%) on contract; some bill on deliverable handover; some bill milestone-based.
Typical defaults. Smaller operators want faster payment; larger ones may accept slower.
Test question. "What are the payment terms, deposit requirements, and milestone billing structure?"
differently
Concrete example. A buyer sends out a brief that says: "100 ha rural site, engineering-grade LiDAR capture, deliverables to support drainage design. Per-hectare quote please."
Operator A interprets engineering-grade as ±30 mm RMSE, 50 ppm² density, full ASPRS classification, comprehensive QA pack, 12-month archive. Quotes $42k.
Operator B interprets engineering-grade as ±50 mm RMSE, 30 ppm² density, basic ASPRS classification, minimal QA pack, 6-month archive. Quotes $28k.
Operator C interprets engineering-grade as ±25 mm RMSE with PPK base log, 75 ppm² density, full ASPRS classification with utility classes, comprehensive QA pack with independent sign-off, 24-month archive. Quotes $58k.
The 100% variance between operators isn't competitive market behaviour — it's three honest interpretations of an ambiguous brief. Each operator quoted what they read; each delivered to their own interpretation.
The buyer comparing on price would pick Operator B. The buyer comparing on what gets delivered would realise the quotes aren't directly comparable without additional specification.
(See reading a capture proposal article for how to spot the interpretation differences in incoming proposals.)
Some items default in ways that affect cost linearly; others have step-function effects. The items where the interpretation difference is most material:
Linear cost effects: density (more = more flight time), accuracy spec (tighter = more control work), QA pack scope (more = more processing time). Operator interpretations on these vary by 20-50% in cost.
Step-function effects: archive retention (default purge vs 12-month retention is a structural commitment), classification scheme (basic vs full ASPRS may be 2× the classification cost), independent QA sign-off (single-team vs two-team workflow is structurally different).
Disproportionate downstream effects: datum interpretation (silent GDA94 vs GDA2020 produces 1.8 m offsets later), buffer interpretation (no-buffer vs 100 m buffer affects effective deliverable area), format interpretation (LAS 1.2 vs 1.4 affects what classifications can be stored).
Once you've sent the brief and received quotes, a single-round clarifying-question email surfaces the interpretation differences. The pattern:
"Quick clarifying questions before we proceed further with comparison. Please confirm:
- RMSE accuracy target at independent checkpoints
- Minimum committed point density
- Horizontal datum (GDA2020 / GDA94), MGA Zone, vertical datum (AHD), and whether EPSG codes will be encoded
- ASPRS classes that will be populated
- Whether captured area extends beyond AOI and by how much
- Deliverable formats with specific versions, tile structure, naming convention, manifest
- QA pack contents and sign-off authority
- Archive retention period and reprocess pricing
- Processing-chain documentation included
- Mobilisation pricing structure and weather no-go arrangements
- Contingency / risk-pricing approach for this project type
- Payment terms and deposit requirements"
Twelve answers reveal the interpretation. Operators who answer all twelve cleanly are giving you the true comparable basis. Operators who push back ("that level of detail isn't usually needed at this stage") are signalling something about how they'll handle the project later.
A nuance: not every item needs explicit specification on every project. Three categories:
Always specify explicitly:
Specify when material:
Leave open with confidence:
Over-specifying inflates cost without value; under-specifying invites interpretation variance. The middle path is specifying the outcome-relevant items and leaving method open.
(See procurement checklist article for the high-leverage items.)
Every project brief has gaps. Operators fill them with industry-standard defaults that vary between operators. The same brief sent to three operators routinely produces three different prices and three different scopes — not from dishonesty but from three honest interpretations of ambiguous language.
Twelve items operators default on with typical default ranges: accuracy spec, density, datum and projection, classification scheme, capture buffer, deliverable format, QA pack scope, archive retention, processing chain documentation, mobilisation model, contingency pricing, payment terms.
Three reasons operators default differently: local- market client base shapes defaults, sensor and processing pipeline drive interpretation, risk tolerance varies between operators.
Some defaults have linear cost effects (density, accuracy, QA scope); some are step-functions (archive retention, classification scheme, independent sign-off); some have disproportionate downstream effects (datum, buffer, format).
Twelve-question clarifying email after receiving quotes surfaces the interpretation differences in a single round. The questions test interpretation, not negotiation.
Three categories of items: always specify (accuracy, datum, format, archive), specify when material (density, classification, buffer, QA), leave open with confidence (sensor, platform, specific processing steps).
Send through the brief and we'll cross-check it against the twelve-item interpretation list before you send it out. The five-minute review prevents the post-tender exercise of clarifying what each operator actually quoted against. Comparable quotes need comparable interpretation; comparable interpretation needs the brief to close the right gaps.
The six highest-leverage items to specify explicitly. This article's twelve-item list extends the checklist into the broader inventory of what operators default on.
The proposal-evaluation companion to this brief-writing piece. Both articles work the same insight from different angles: what's missing from the document is where the real interpretation happens.