App Overview

Angles - Video Goniometer icon

Angles - Video Goniometer

Nathaniel Cochran · Utilities

This goniometer tool can be used to measure angles at various times in a video

$0.99 · In-app purchases

PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.2
5 ratings · Top 30%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Rork plan preview for Angles - Video Goniometer: map the core Utilities workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Provide calibration options to improve accuracy.

Assumption to check: Limited measurement accuracy can frustrate users.

Validate with people who use this workflow before building.

Hypothesis 2

Simplify UI by reducing unnecessary elements.

Assumption to check: User interface can feel cluttered.

Validate with people who use this workflow before building.

Hypothesis 3

Optimize camera usage to enhance performance.

Assumption to check: Inconsistent performance on older devices.

Validate with people who use this workflow before building.

Hypothesis 4

Integrate onboarding tutorials for first-time users.

Assumption to check: Lack of detailed usage instructions.

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

This goniometer tool can be used to measure angles at various times in a video. Designed for rehabilitation professionals. Features: • Capture new videos or import existing videos from your library • Step frame-by-frame through a video, or drag the slider to seek to a specific time • Select points and drag them into place • Lines and angle measurements automatically appear, connecting the points • Repeat with more frames, points, and angles • Export to spreadsheet (.xlsx format) for further calculations and analysis (note that there are multiple worksheets - one with raw point coordinates, and one with angle measurements) Make sure to capture your video directly perpendicular to your subject, with the camera level in all planes, and without panning the camera. The display of angle labels can be turned on/off in the app's preferences, found in the Settings app. App developer: Nathaniel J. Cochran, in collaboration with Regina Harbourne Supported by Duquesne University, Physical Therapy Dept. in the Rangos School of Health Sciences Developed in part to support a grant from the Institute of Education Sciences, US Dept. of Education

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Screenshots

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Build scope

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Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
React Native
Expo
react-navigation
@react-native-async-storage/async-storage
expo-camera
react-native-reanimated
BUILD KIT DIFFICULTY
Intermediate

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.