Importing and Managing Survey Field Data

Why Field Data Management Matters

Survey crews collect dozens to hundreds of point observations in a single day. Every one of those shots—northing, easting, elevation, and a descriptor code—must move from the field instrument into a GIS without losing accuracy or introducing new errors. A single transposed coordinate or wrong delimiter can shift a point by hundreds of meters or crash an import entirely. This lab teaches you to import, inspect, and repair that data before it ever reaches a final map or legal document.

Understanding the CSV Survey File

Field data collected by a total station or GNSS receiver is commonly exported as a comma-separated values (CSV) file. A clean survey CSV typically contains columns in this order: Point ID, Northing, Easting, Elevation, Descriptor. For example:

```

PT_ID,NORTHING,EASTING,ELEV,DESC

1,3847221.54,412088.32,245.10,IP

2,3847198.77,412102.45,244.85,MON

```

Common import errors you will encounter in this lab include:

• Wrong delimiter — a semicolon or tab used instead of a comma, causing all fields to merge into one column.
• Swapped X/Y (Easting/Northing) — when columns are reversed, points appear mirrored or displaced by large distances.
• Mixed or missing coordinate reference system (CRS) — points plot in the wrong part of the world if the CRS assigned during import does not match the data's projection.

Always open a CSV in a plain text editor before importing. Confirm the delimiter, count the columns, and verify that sample coordinates fall within the expected geographic region by checking against known control.

Importing Points with ArcGIS Pro's XY Table to Point Tool

In ArcGIS Pro, use Map → Add Data → XY Point Data or the XY Table to Point geoprocessing tool (Data Management Tools → Features). Steps:

1. Add the CSV to your project as a table.

2. Open XY Table to Point. Set X Field to the Easting column and Y Field to the Northing column. Elevation maps to Z Field if you want a 3D feature class.

3. Set the coordinate system to match the field data—commonly a State Plane or UTM zone in US feet or meters.

4. Run the tool and inspect the output. Zoom to the layer and compare point positions against a reference layer (aerial imagery or parcel boundary).

5. If points appear in the wrong location, return to the CSV, confirm column order, and re-run with corrected field assignments.

Verification: After import, use Identify or attribute table inspection to confirm that point PT_ID 1's coordinates match the CSV source values exactly.

Digitizing a Field Sketch in QGIS

A field sketch is a hand-drawn diagram showing boundary corners, ties, and descriptors. When georeferenced aerial imagery is available, you can trace the sketch as a polyline or polygon layer.

1. Load the GeoTIFF aerial image into QGIS. Confirm its CRS matches your project.

2. Create a new temporary scratch layer or shapefile: Layer → Create Layer → New Shapefile Layer. Choose Polyline geometry. Add fields for PT_ID (integer) and DESC (text).

3. Toggle editing (pencil icon), select the Add Line Feature tool, and click each vertex along the lot boundary following the field sketch.

4. Attribute each vertex's point ID and descriptor by editing the attribute table after digitizing.

5. Close the polyline by snapping the final vertex back to the first. Enable snapping (Project → Snapping Options) and set tolerance to at least 1 pixel. A closed boundary that does not snap will fail geometry checks.

Safe file practice: Save edits frequently. QGIS does not auto-save edits to a shapefile layer. A power interruption or software crash before saving can lose all digitizing work.

QA/QC: Geometry Checks and Repairs

Topology errors—gaps, overlaps, self-intersections, and unclosed rings—prevent data from being used in area calculations, parcel overlays, or legal plat generation. Two tools address this:

• QGIS Check Geometry (Vector → Geometry Tools → Check Geometries): Scans a layer and reports each error with its feature ID and error type. Export the results to a log.
• ArcGIS Pro Repair Geometry (Data Management Tools → Features → Repair Geometry): Attempts to automatically fix detected topology errors. Run Check Geometry first to document what existed, then Repair Geometry, then Check Geometry again to confirm all errors are resolved.

Document every error in your QA/QC log: feature ID, error type, before-repair status, after-repair status, and your initials with date. This log is a legal record of data quality and is required for the completion check of this lab.

Safety and Data Integrity Notes

• Coordinate backups: Before editing or repairing any dataset, save a copy to a separate folder. Never repair the only copy of field data.
• CRS discipline: Always confirm that every layer in a project shares the same CRS or that on-the-fly projection is understood. Mixing NAD83 State Plane feet with NAD83 UTM meters produces errors that are not always visible until a measurement is performed.
• Personal safety in the office: Workstation ergonomics matter during long digitizing sessions. Adjust chair height, monitor distance, and take short breaks to prevent repetitive strain injury.
• File naming: Use a consistent naming convention (e.g., `PROJ_DATE_INITIALS_v01`) to prevent overwriting corrected files with uncorrected ones.

Connecting to Credentials

The Esri ArcGIS Pro certification tests your ability to import, manage, and troubleshoot feature data—exactly the skills practiced here. The NSPS CST Level 1–2 exam expects technicians to understand survey data formats, coordinate systems, and basic QA/QC. FAA Part 107 is less directly connected to this lesson, but drone-collected photogrammetry outputs are delivered as point clouds and GeoTIFFs that enter the same GIS workflow you are learning today.