How to Use the Survey GIS Workspace

There are two main ways to add points: enter them in the Point Manager, or create them directly on the map with the Point tool. For a small survey, Point Manager is usually the easiest because you can enter or edit the point ID, Easting, Northing, RL and code in one place.

1. Open the GIS workspace and check the Project Information settings first. Choose your units and the appropriate coordinate reference system.
2. Use + Add in Point Manager to create a row.
3. Enter a unique point name/ID and the coordinate values. Add RL and Code where relevant.
4. Use Validate to check the point set for obvious problems.
5. The point is plotted on the map when its coordinates can be interpreted in the active project system.

You can also activate Point and click on the map to create a point from a map position. For professional work, treat map-created positions as approximate unless they are tied to verified project control. The workspace itself reminds you to verify project control before professional use.

CSV is the quickest option when your survey data is already in a spreadsheet-like file. Click CSV in the top toolbar and select your file.

Your file should contain recognizable fields for the point identifier and coordinates. Common headings include Point, Point ID, Name, Easting, Northing, North, East, RL/Elevation and Code. Keep the coordinate columns numeric and avoid mixing notes into coordinate cells.

1. Set the project units and CRS before or immediately after import.
2. Click CSV and choose the file.
3. Review the imported point count and the Point Manager.
4. Run Validate.
5. Use Zoom to Survey if the imported points are not immediately visible at the current map extent.

If the points appear in the wrong part of the world, do not start editing values blindly. First check whether the file contains geographic longitude/latitude, UTM coordinates, Nigerian Grid coordinates, or another local system, and make sure the project CRS matches the source data.

For a parcel boundary, the most reliable workflow in this workspace is to put the boundary points in their survey order and calculate a Closed traverse.

1. Import or enter the boundary points in the order they occur around the parcel.
2. Check the point order in Point Manager. Use Reverse order if the direction needs to be reversed.
3. In Plot Area / Traverse, select Closed traverse.
4. Click Calculate or the top Calculate Area button.
5. Review the calculated area, perimeter and traverse results.

The closing leg is calculated automatically for a closed traverse. You do not normally need to repeat the first point; the workspace ignores a repeated first point in the area computation.

If the area is wrong, the first things to check are point order, duplicate points, units and CRS. A boundary with points in the wrong order can cross itself and produce a misleading area.

Use the Distance tool in the map toolbar when you want a quick map-based measurement. Activate Distance, then click the vertices of the route you want to measure. The live measurement updates as you add segments.

This is useful for checking a route, measuring between several map locations, or taking a quick distance without changing your survey point list. When you are finished, use the distance tool's clear option if available in the live measurement control, or use the map clearing controls as appropriate.

If you want a survey traverse distance based on named survey points, use the Plot Area / Traverse workflow instead. That gives you leg-by-leg survey results and closure information rather than simply measuring a line on the map.

Always confirm units before relying on a measurement for reporting. Map measurements can also differ from field observations if the data is in the wrong CRS or has not been correctly transformed.

Use Point Tools → Divide Line. This is useful when you need regularly spaced intermediate points between two known survey points.

1. Open Divide Line.
2. Select the start point and end point using the point selectors.
3. Enter the number of equal parts required.
4. Choose Calculate / Create.
5. Review the newly created intermediate points in Point Manager and on the map.

For example, dividing a line into four parts creates three intermediate points between the two end points. Check the resulting point IDs and coordinates before using the derived points in a professional deliverable.

Use Point Tools → Bearing / Distance when you know a starting point, a direction and a distance to the new point.

1. Open Bearing / Distance.
2. Select the starting survey point.
3. Enter the North Azimuth or bearing required by the tool.
4. Enter the distance and confirm the units.
5. Click Calculate / Create.

The workspace uses the entered direction and distance to derive the new coordinate. Before accepting the result, confirm that you entered the direction in the expected convention and that your distance units match the project. If you are working from quadrant bearings rather than an azimuth, convert them correctly before entering the value.

Activate Midpoint in the map toolbar, then click the two existing survey points that define the line. The workspace calculates and inserts the point halfway between them.

The midpoint is a derived survey point, so after it is created you can review its coordinates and point code in Point Manager. If you need the midpoint of a specific coordinate line rather than two map-picked points, make sure you select the exact endpoints of that line.

Use the search box at the top of the map. You can search for an address, area or coordinates. Enter the location and click Search.

For coordinate searches, use decimal coordinate notation where possible and make sure the order is clear. If the search returns a location, select the result to move the map to it. Zoom to Survey is separate: it brings your existing survey points and project extent into view.

Remember that a map search locates a place; it does not automatically turn that location into a field-control point. If you need a survey point at that position, create one deliberately and verify its coordinates and datum.

The coordinate system should match the coordinate system of your source survey data. The workspace provides WGS84 Geographic, explicit WGS84 / UTM Zones 31N, 32N and 33N, and explicit Nigerian Grid West, Mid and East Belts.

WGS84 Geographic is appropriate when your coordinates are latitude/longitude. UTM is appropriate when your survey is represented as projected UTM Easting/Northing values. Nigerian Grid is appropriate when your project data is in the Nigerian Grid system.

Do not choose a CRS simply because it produces numbers that look plausible. The same physical location can have very different coordinate values in different systems. If your survey file came from a GNSS receiver, total station workflow, CAD drawing or another survey package, confirm the source CRS and datum from that project's documentation.

Select the project CRS explicitly. The workspace provides UTM Zones 31N, 32N and 33N plus the Nigerian Grid West, Mid and East Belts.

For Lagos, WGS84 / UTM Zone 31N is normally the appropriate UTM project zone. Confirm the CRS and datum from the survey controller or project documentation before importing survey coordinates.

The selected zone or belt remains fixed for the project; it does not change when the mouse moves across the map.

Enter or import the traverse points in their correct order, then open Plot Area / Traverse. Select Closed traverse for a parcel or closed traverse and click Calculate.

The results show the traverse geometry and closure information. A perfect mathematical closure is uncommon in observed field data; the important question is whether the closure error is acceptable for the survey's purpose and specification.

If the closure is unexpectedly large, first check point order, duplicate points, transcription errors, units and CRS. Only after those checks should you move to an adjustment method such as Bowditch or Transit.

Use Survey Report / Print / PDF from the workspace. Before generating it, give the project a meaningful name, enter the site/location, confirm units and CRS, and review the point table and calculated results.

For a professional report, also review any adjustment or transformation you applied. Raw coordinates should remain distinguishable from adjusted/transformed coordinates, and you should verify control and survey assumptions before issuing the document.

Open Point Tools → Point on Line, select the two endpoints that define the line, then specify the required position along that line using the tool's controls. Create the derived point and check it in Point Manager.

This is useful when you need a point at a known fraction or position along an existing survey line. Make sure the endpoints are selected in the intended direction because the position can depend on the start/end definition.

Open Point Tools → Offset Point. Select the source line or the points defining it, enter the required offset information, then create the point.

Before accepting the result, confirm which side of the line the offset represents and whether the offset distance is being entered in project units. This tool is useful for setting out parallel or perpendicular relationships, but the resulting point should still be checked against the intended field geometry.

Open Point Tools → Intersection. Select the two line definitions using the point-picking controls, then calculate the intersection. If the lines do not have a valid intersection in their defined geometry, the tool may not produce a usable point.

Check that you selected the correct endpoints and that the lines are not parallel or nearly parallel. After creation, inspect the intersection point and its coordinates in Point Manager.

Use Point Tools → Perpendicular. Select the reference line and the point from which the perpendicular relationship is required, then calculate/create the derived point.

Perpendicular constructions are especially useful for offsets and setting-out geometry. Verify the reference line and the side/direction of the construction before using the point in a deliverable.

Use the Point Manager table. Edit the coordinate, RL, code or other editable field directly in the point row, then allow the workspace to refresh the map and calculations. Use the row's delete control when a point should be removed.

After significant edits, run Validate and recalculate the traverse. If the point participates in a boundary, changing it can affect area, perimeter, closure and adjustment results.

Point order matters for traverse calculations and polygon area. Use Reverse order in Point Manager when you need the existing sequence reversed.

Reversing the order changes the direction in which the traverse is processed. It does not change the physical coordinates of the points. Always recalculate the traverse afterward and check the resulting bearing/distance sequence.

The Show adjusted coordinates option lets you inspect the adjusted coordinate set after you have previewed/applied an adjustment. It helps you compare the original/raw survey coordinates with the coordinates resulting from the selected adjustment method.

Keep in mind that an adjustment is a calculated correction, not proof that the underlying observations were correct. Review the closure and residuals and preserve the raw observations/coordinates for auditability.

The Point Manager can mark points as locked controls. This identifies points that should be treated as fixed control rather than ordinary free points in the professional workflow.

Use control locking deliberately. A point should only be treated as fixed when its control status has been independently established. Do not lock an arbitrary map point simply to force an adjustment to behave as expected.

A north azimuth is an angle measured clockwise from north. An azimuth near 0° points north, 90° points east, 180° points south and 270° points west. Therefore an azimuth around 200° points generally south-west.

The workspace's Bearing / Distance tool uses the North Azimuth convention. If your field notes use quadrant bearings such as S 20° W, convert that bearing to the corresponding azimuth before entering it.

UTM divides the world into longitudinal zones, but a professional survey project should use one deliberate project CRS. Select Zone 31N, 32N or 33N explicitly and keep it fixed for the project.

The map cursor does not change the project zone. This prevents survey coordinates from being silently reinterpreted when the cursor moves.

Use Nigerian Grid when your survey data, project specification or existing control is defined in the Nigerian Grid reference system. It is particularly important when your survey must fit existing Nigerian cadastral, engineering or control data that uses that system.

If your source data is WGS84 latitude/longitude or UTM, do not switch to Nigerian Grid merely because the project is in Nigeria. Confirm the source datum, projection and required transformation first.

Select the project belt explicitly: West, Mid or East. The selected belt remains fixed for the project.

For imported survey data, confirm the belt and datum from the survey controller or project documentation before importing.

A coordinate reference system describes how a position on Earth is represented numerically. Changing from geographic latitude/longitude to a projected system such as UTM or Nigerian Grid changes the coordinate values even though the physical point is intended to remain in the same place.

Large-looking changes in the numbers are therefore not automatically an error. What matters is whether the transformed point lands in the correct physical location and whether the source datum and target CRS were correctly identified.

Use the Coordinate Transformation panel. Choose the Source CRS, choose the Target CRS, select the appropriate datum/Helmert method where applicable, then click Preview transformation.

Review the preview before applying it. The workspace is designed to let you inspect the transformation before changing the working coordinates. For Minna/WGS84 work, the available methods include the DMA/EPSG default method and the Shell/EPSG 1754 southern Nigeria method.

Transformation parameters are not interchangeable. If your source project has a known datum transformation specification, use that specification rather than choosing a method based only on which result looks closest.

Raw coordinates are the original coordinate values in your project. Adjusted coordinates are coordinates modified by a survey adjustment such as Bowditch, Transit or coordinate least-squares. Transformed coordinates are coordinates converted from one reference system/datum to another.

These are different operations. An adjustment addresses survey network misclosure or observation consistency; a transformation changes the coordinate reference framework. Keep them conceptually separate and document the order in which operations were applied.

Traverse closure describes how closely the calculated traverse returns to its expected closing position. In a closed traverse, the final computed position should agree with the starting point. Any discrepancy is the closure error.

Closure error can come from observation uncertainty, instrument limitations, field conditions, transcription mistakes, incorrect point order, wrong units or an incorrect coordinate system. The workspace helps you quantify the result; professional acceptance still depends on the survey specification and control requirements.

First calculate the closed traverse and inspect its closure. In the Adjustment panel choose Bowditch / Compass Rule, then click Preview adjustment.

Review the proposed corrections before clicking Apply adjusted coordinates. Bowditch distributes the coordinate corrections in relation to traverse leg lengths, making it a common approach when angular and distance errors are treated in a balanced way.

Do not apply an adjustment simply because it makes the traverse close. Confirm that the closure is reasonable and that the adjustment method is appropriate for the survey.

Choose Transit Rule when your adjustment workflow calls for corrections distributed in relation to the coordinate components rather than the same length-based rule used by Bowditch.

As with any adjustment, preview the corrections first and compare them with the size and pattern of the original closure. The appropriate method depends on the survey's observation characteristics and required standards; the software should not be used to decide that on its own.

The workspace provides Coordinate Least-Squares (equal leg weight) as an adjustment option. Least-squares adjustment estimates a set of coordinates that best satisfies the mathematical constraints under the weighting assumptions used by the calculation.

The important phrase here is equal leg weight. Real survey networks can require observation-specific weights based on measurement precision. If your professional workflow requires a rigorous stochastic model, do not assume this simplified option is equivalent to a full instrument-observation least-squares network adjustment.

Calculate the traverse first and inspect the closure error and relative closure shown in the results. Then compare the result with the tolerance required for the type of survey you are performing.

If the error is unexpectedly high, troubleshoot before adjusting: verify point IDs, point order, repeated points, coordinate values, units and CRS. A bad input dataset can be mathematically adjusted while remaining fundamentally wrong.

Before applying an adjustment, use Preview adjustment and review the proposed coordinates. Raw coordinates are intended to remain distinguishable from adjusted coordinates until you apply the adjustment.

If you need to preserve an audit trail, export or record the raw dataset before applying changes. When testing different methods, it is safer to work from a known raw dataset so that one adjustment does not become the starting point for another unintentionally.

Use one survey point per row with clear column headings. The safest structure is a point identifier plus coordinate columns, for example Point, Easting, Northing, with optional RL and Code.

Avoid merged cells, formulas that have not been converted to values, thousands separators inside coordinate numbers, and inconsistent decimal separators. If your source software exports a different heading such as North/East, review the imported table carefully to make sure the values are mapped to the intended axes.

Click Excel in the toolbar and choose your .xlsx/.xls file. Select the sheet containing the survey points if prompted by the import workflow, then inspect the resulting Point Manager entries.

Excel files often contain title rows, notes, multiple sheets or formatted cells. The cleaner the source sheet, the less ambiguity there will be during import. After importing, validate the point set and confirm that Easting and Northing have not been swapped.

Yes. Use the KML/KMZ import control. KML/KMZ is useful when your data is already represented as geographic map features.

Because KML normally uses geographic coordinates, confirm how the imported features relate to your project's working CRS. Treat a KML import as a data-transfer step, not as proof that the source file has the survey accuracy or datum you need.

Yes. Use the GeoJSON import control. GeoJSON is useful for point and geometry exchange with GIS applications.

After import, inspect the resulting layers and points, check the coordinate reference information where available, and verify the geometry before combining it with survey-control data.

Yes. Use the DXF import control. DXF is particularly useful when survey geometry has been supplied from CAD software.

CAD drawings can contain multiple layers, construction geometry, text and objects that are not survey points. After import, inspect the created layers/features and make sure the drawing's units, origin, coordinates and intended CRS match the project before using the geometry for calculations.

Use the Import / Export panel at the bottom of the workspace. You can export to CSV or Excel, as well as other supported formats such as KML and GeoJSON.

Before exporting, decide whether you want the raw or adjusted coordinate view represented in your workflow. Review the point table and project settings first so the exported data is clearly associated with the correct project and coordinate system.

Choose the corresponding export button in Import / Export. KML is useful for geographic viewing, GeoJSON for GIS interchange, and DXF for CAD workflows.

These formats serve different purposes. A visually correct file in Google Earth or CAD does not automatically establish survey accuracy. Keep the source coordinate system and project metadata with the exported deliverable.

The most common causes are an incorrect CRS, swapped Easting/Northing columns, degrees interpreted as projected coordinates, wrong units, or a datum/projection mismatch.

Check the source file's documentation first. Compare one known control point from the source against the same point in the workspace. If the discrepancy is systematic, investigate the CRS/datum transformation rather than manually shifting every point.

Use the Leaflet map's layer/basemap controls to switch between the available map backgrounds. Satellite imagery is useful for visual context, checking access and comparing survey features with visible ground features.

Do not treat satellite imagery as survey control. Its imagery date, orthorectification and positional accuracy may not meet the requirements of a professional survey.

Use the Grid checkbox in the map tools overlay. The grid is a visual reference intended to help you understand map position and orientation.

If the grid appears inconsistent with your survey coordinates, check the project CRS rather than assuming the grid itself is wrong.

Enable Point labels in the map tools overlay. Labels make it easier to identify survey points while checking point order and geometry.

If labels become crowded, zoom in or temporarily disable them. The point ID in Point Manager remains the authoritative identifier for editing.

Enable Bearing / distance in the map tools overlay. The map can then display line-related information to help you visually inspect traverse geometry.

Use these labels as a convenient map check. For formal reporting, rely on the calculated traverse results and exported report rather than reading values from a crowded map.

Use the North arrow and Scale bar checkboxes in the map tools overlay. These are presentation aids that help orient and interpret the map.

The scale bar is particularly useful when viewing the map at different zoom levels because it updates with the map scale. The north arrow indicates map orientation, which is not necessarily the same thing as a survey grid convergence diagram.

First check that the corresponding checkbox is enabled. Then make sure the map is fully loaded and that the feature is not hidden by the current viewport or a dense set of other map elements.

If points are off-screen, use Zoom to Survey. If the map looks generally correct but coordinate-dependent elements are unexpected, check the project's CRS and the imported data rather than repeatedly toggling display options.

Click the ⌖ button beside the map search field, labelled Zoom to survey. It adjusts the map view so your survey data can be brought into view.

This is especially useful immediately after importing a CSV, Excel, KML, GeoJSON or DXF file when the new data is outside the current map extent.

Separate visual correctness from coordinate correctness. A point can appear in a plausible location on a basemap while still using the wrong datum, projection or axis order.

Use a known control point to compare expected and displayed coordinates, confirm the source CRS, inspect units, and only then perform a deliberate transformation if required. The GIS workspace is a calculation and visualization aid; professional survey control must be independently verified.

A good general workflow is: set project information → establish CRS/units → import or enter control and survey points → validate → inspect the map → calculate traverse/area → inspect closure → preview adjustment if required → apply only after review → export/report.

This order reduces the chance of calculating a correct mathematical answer from incorrectly interpreted data. Keep your original/raw dataset available before applying transformations or adjustments.

Check the point order first. Then check whether the field result uses the same units, coordinate system, boundary definition and closing point. Differences can also arise when one result uses ground distances while another uses grid/map distances.

If the discrepancy is significant, compare individual traverse legs rather than only the final area. That usually makes it easier to identify the first point at which the datasets diverge.

Check that the correct source points were selected, the units are correct, the bearing convention is correct, and the relevant line geometry is valid. For intersection/perpendicular/offset tools, nearly parallel or ambiguous geometry can also produce unexpected results.

After creating a derived point, inspect its coordinates and relationship to the source geometry before using it in another calculation.

The workspace is intended as a practical browser-based surveying and mapping tool for calculations, visualization, data preparation and professional workflow support. It should not be treated as a substitute for independent field verification, approved control, instrument observations, statutory requirements or a rigorous survey adjustment package where those are required.

Always verify project control and review calculations before issuing professional survey information.

The current GIS workflow is session-based. Survey work is held in the browser workspace rather than being treated as a server-side project record. If the data is important, export it and keep a project copy before closing or clearing the workspace.

Use the export controls to preserve your points and relevant deliverables, and keep a record of the CRS, datum, units and adjustment/transformation choices used.