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RESEARCH

Topics under consideration for building this site, and research for future projects.

1. Datum modernization — NATRF2022 / NAPGD2022

The National Geodetic Survey is modernizing the national datums. The new terrestrial reference frame (NATRF2022) and geopotential datum (NAPGD2022) are expected to replace NAD83 and NAVD88 (federal adoption targeted around 2027). These new datums are NOT official yet. Nothing on this site publishes new-datum values as official, and new-datum values are never mixed with current values without a label. This section tracks the modernization so the site is ready when it becomes official.

2. Control quality and evaluation

A monument's quality classification rises only on uploaded evidence — inverse results or an actual check shot. Without evidence it stays exactly as published. City monuments keep their original classification; field findings attach as a separate note and never silently replace the official coordinates. Evaluation means multiple measures at different times, enough values to average. Photos, directions, and landmarks improve access quality (findability) only — never monument quality.

3. Control quality by observation method — general information

There is no single modern table that turns a method name into a grade. Two layers are used today, and they must not be mixed up. Legacy FGCC Order/Class classified a network adjustment (for example, horizontal distance ratios and vertical mm per square root of kilometres). Current practice, under FGDC standards and NGS 92 (October 2024), publishes network accuracy and local accuracy separately, at 95% confidence, in metres, from a least-squares adjustment — horizontal and vertical separately. A point can be strong horizontally and weak vertically, and that difference must stay visible.

In general terms, for horizontal work: long multi-hour static networks rank highest, followed by long static, then fast or rapid static, then repeated network RTK with several occupations on different days and times, then single-base RTK, then a single short RTK topo shot. A 2–4-second topo shot is not control on its own: it has no redundancy, no independent geometry, and no defence against multipath or a bad ambiguity fix. For vertical work, a closed digital level loop tied to trusted benchmarks remains the check on GNSS orthometric heights, because GNSS height error includes ellipsoid-height error plus geoid-model error. Averaging must be across independent occupations at different times, not across epochs inside one initialization.

NGS 92 classes for GNSS control surveys (95% confidence; feet conversions are shown for readers unfamiliar with centimetres): Primary — horizontal 1 cm (0.033 ft), ellipsoid height 2 cm (0.066 ft), orthometric height 3 cm (0.098 ft); Secondary — 1.5 cm (0.049 ft), 3 cm (0.098 ft), 4 cm (0.131 ft); Local — 2.5 cm (0.082 ft), 5 cm (0.164 ft), 6 cm (0.197 ft). These are class limits, not a substitute for a point's own computed accuracy: the published number for each point must be its own local and network accuracy, with the observation method, repeats, and checks behind it recorded.

Precise Point Positioning (PPP) is a single-receiver method using precise orbits and clocks, not a local base, and its output is natively in an ITRF frame at the observation epoch — not NAD83. A PPP result is only interpretable with its service, orbit product, session length, frame, epoch, and transformation recorded. A traverse gives strong local relative geometry when closed and adjusted between known control points, but its absolute position is inherited from the control it starts from; a single radial spur is not control.

Rules for uploading new controls

Guidance for anyone submitting a new control point to this site.

Coordinates are reviewed against city, county, and address. The zone is asked for when the coordinate system requires it. The elevation type (orthometric, ellipsoidal, etc.) is asked for and tagged "(not specified)" when missing. Review shows each control on a zoomed-in aerial view — a point in a river or far from a road means something is wrong. Photos and directions are optional, and a submission's usefulness rating depends on how much information the uploader provides.

What this is

Control Point Texas is a shared, free database of Texas survey control — city benchmarks, monuments, and control points — built so a surveyor starting a job can find trustworthy control near the work area in minutes instead of half a day. Type in your job location (latitude/longitude, UTM, State Plane, or a city), set how far you're willing to look, and the site returns the control around that point: where it is, what it is, when it was last verified in the field, and files ready for your data collector.

A note on zones and accuracy. Some points were published with the zone assumed — Texas State Plane North Central 4202 — where the source did not state a zone. That means a few points from outside the North Central area may sit a little off their true position until they are checked in the field. Treat non-verified points as leads: verify them in the field before you rely on them, and report what you find. That field reporting is what keeps this database alive and makes it more accurate over time.

About this review data

Fort Worth coordinates are published as-is by the City of Fort Worth. Pedro's own field work has found that database can sit off the ground in places (sometimes ~70–300 ft); treat city coordinates as the source of record and verify in the field. Master-subset coordinates in State Plane feet were converted to latitude/longitude assuming Texas State Plane North Central zone 4202 where the zone was blank; rows that fell outside the North Central range were left out (see counts below). Only public-safe rows are published here — no held rows, company-named rows, or restricted rows.

Beta feedback — one question at a time

Rather than a long survey, there's one question here. Answer it, copy your answer, and paste it back in the chat.

Question 1 of the beta:

After a surveyor downloads control and visits the points, how should we remind them to report back what they found?