Measurement Tools on the Map

Back from the field, the first questions are always the same: "How long is this line? What grade is that slope? What elevation is that point?" You do not need to move the file into another program to answer them. On the CartaX map the measurement tools sit in a single toolbar, the result is readable right on the map, and every drawing is saved to the project. This guide covers the tools, the profile chart that gives three results from one line, and how to manage and share measurements.

Four tools in the toolbar

The measurement toolbar sits along the bottom edge of the map. Drawing works the same way in every tool: left click adds a point, right click finishes the measurement, Cancel abandons it.

Tool	What it gives you
Line measurement	Horizontal distance of a multi-point line; with elevation data, also the elevation difference, the slope and a 2D profile chart
Area	Horizontal area of a closed polygon
Line of sight	Whether the view between two points is clear or blocked, plus total, visible and blocked length (3D view only)
Point	Coordinates and elevation of the clicked point

The map label of the Point tool has three lines — X/E, Y/N and Z/U — the convention surveyors know from their controllers. The panel row shows latitude/longitude, the name of the coordinate system and the elevation. While a tool is active, a palette button next to it lets you set the Style of the drawing (colour, solid or dashed line, width, fill) before you even finish.

Values follow your unit preference: Metric (m, m², m³) or Imperial (ft, ac, yd³). Terrain exaggeration in the 3D view is visual only; measurement and the profile chart always use the real elevation.

One line, three results: the 2D elevation profile

What sets the Line measurement tool apart is the draggable chart window that opens when you finish the line. If the selected orthophoto has a DSM/DTM attached, or the elevation is read from the Surface source, the window draws the relief of the line and lists three results side by side in its bottom line:

Result	Meaning
Distance	Horizontal length of the line
ΔH	Difference between the lowest and highest elevation along the line
Slope	Average grade between the two ends of the line, as a percentage and in degrees

The window has three tabs: All overlays the relief with the straight grade line joining the two ends, Slope brings the grade line to the front, and Profile focuses on the relief and adds the min and max elevation. Chart and map are linked: move the cursor across the chart and the same point is highlighted on the line in the map, with its distance and elevation shown; hover along the line on the map and the chart follows.

Two details are easy to misread. ΔH is a range along the line while the slope is measured end to end, so on a rolling line ΔH divided by distance will not equal the slope — that is deliberate. The slope carries no direction; starting the line from the other end does not change the result. Without elevation data the line still gives horizontal distance, but no chart opens.

Which surface the elevation comes from: the settings button

You choose the elevation source with the Ayar (settings) button on the orthophoto row. The elevation source row offers three options:

• Surface — the rendered model surface; the layer's visual height adjustment does not affect elevation
• DSM — the upper surface including buildings and trees
• DTM — bare ground

Only the models you have uploaded can be selected. If no elevation model is attached, the tool says so: "No DEM — elevations are read from the surface you click." Use DTM when you measure the ground and DSM when you measure roof or tree height; the DSM vs DTM guide explains how that choice changes the result.

Managing measurements

Every drawing is saved automatically to the Measurements list beneath its orthophoto in the layer panel — in the panel's own words, "Anything you draw from now on is saved here automatically." Each row shows the measured value and the name you gave it. Clicking a row zooms the map to that measurement; for line measurements the chart window reopens. The row buttons let you:

• Show / Hide — take the measurement off the map without deleting it
• Style — colour, line type, width, opacity and fill
• Edit vertices — move the corners of area and point measurements
• Rename and Delete

Measurement records are attached to the selected, ready orthophoto. If the project contains a 3D model, CartaX asks which model the measurement should be grouped under; Free measurement (map) writes it to the general measurement folder instead. With no orthophoto selected and no model, the drawing stays in the session only, and the tool warns you.

Measurements in shares

When you share a layer, the measurement records linked to it are included in the share package automatically; the recipient sees them under the measurements section. Recipients can measure too, but their own drawings are held in browser memory as Temporary measurements and disappear when the page is refreshed. See the PIN-protected sharing guide for details.

Volume and the other workspaces

There is no volume tool in the map toolbar; volume is calculated in two places. The Volume tool in the point cloud viewer gives a rough estimate based on a fixed depth assumption; real cut-fill comes from the difference between two epochs in the Analysis workspace. The volume calculation guide explains the limits of both.

The same toolbar applies on 3D models. The point cloud viewer has its own tool set: Distance, Area, Height, Profile, Angle, Point, Circle and Volume.

Frequently asked questions

Question	Answer
I drew a line but no chart opened?	The selected orthophoto has no DSM/DTM and no surface elevation can be read; horizontal distance is still calculated
Why do ΔH and slope disagree?	ΔH is the min–max range along the line, slope is end to end; they differ on rolling terrain
Why is the line-of-sight tool disabled?	Line of sight requires the 3D view
Where was my measurement saved?	In the Measurements list beneath the selected orthophoto in the layer panel
Are a guest's measurements permanent?	No — they live in session memory and are cleared on refresh
Where is volume?	A rough estimate in the point cloud; real cut-fill in the Analysis workspace