App Overview

iSailGPS NZ : Nautical Charts icon

iSailGPS NZ : Nautical Charts

James Associates Inc. · Navigation

Unleash the navigation potential of your iPhone or iPad with SailGPS NZ! Turn your device into a high-performance GPS receiver with LINZ RNC Nautical Charts, even without a cell signal!

$0.99 · In-app purchases

PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
N/A
No ratings yet

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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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

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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> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for iSailGPS NZ : Nautical Charts: map the core Navigation 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

Implement offline maps and caching for better usability.

Assumption to check: Limited offline capabilities for navigation

Validate with people who use this workflow before building.

Hypothesis 2

Enhance search with filters and auto-suggestions.

Assumption to check: Poor search functionality

Validate with people who use this workflow before building.

Hypothesis 3

Add user comment sections and ratings for charts.

Assumption to check: Lack of user reviews or social features

Validate with people who use this workflow before building.

Hypothesis 4

Provide options for exporting routes to other apps or devices.

Assumption to check: No integration with other navigation tools

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

Unleash the navigation potential of your iPhone or iPad with SailGPS NZ! Turn your device into a high-performance GPS receiver with LINZ RNC Nautical Charts, even without a cell signal! Caught in a storm on the water and your chart plotter fails? Don't worry! Download this app now and regain navigation capabilities to safely return to port. Better yet, buy iSailGPS NZ today ensuring you're prepared for any situation, even in areas with no cell service. One Low Price! Everything included. No sign-ups, ads, subscriptions or in-app purchases. Completely respects your privacy. Unrivaled Features to Enhance Your Journey: TRACKS, WAYPOINTS & ROUTES Record tracks as you sail, even in the background. View them on the chart and in a Speed & Course Over Ground graph. Mark waypoints precisely using charts or satellite maps, place names or addresses, geotagged photos, or by projecting from a known point. Set a quick GoTo waypoint or a full route and see the course (COG), heading (HDG), bearing (BRG), direction, distance, cross track error (XTE), Velocity Made Good (VMG) and Estimated Time of Arrival (ETA) at your destination and intermediate points. Perfect for racing enthusiasts. In a Man Overboard (MOB) emergency a single button press marks your current position & starts navigating to it. Create customized routes using waypoints, recorded tracks, or imported GPX, KML or TCX files. Advanced route editing. Send GPX and KML waypoint, route, track and map list files via AirDrop, eMail, Messages or iCloud Drive. View the sun & moon position and rise & set times for any date and place on earth. Send data to other apps such as Google Earth. LAND INFORMATION NEW ZEALAND RNC MARINE CHARTS Access all LINZ NZ Raster Nautical Charts with no extra charge. These charts had their final update on 7/12/23. There will be no further updates. Our charts are optimized to download faster using WiFi or cell service. Store a few charts or charts for the whole country to use anytime without cell service. Stitches Mercator charts & automatically switches between downloaded charts as you sail. Choose detailed or overview charts. Enjoy the high resolution and what's-all-around detail of these NZ Nautical Charts (RNC). They are a welcome advantage over Vector Charts, which only show a coastline, depths, navigation aids, and minimal details. Print and Share chart images overlaid with waypoints, routes & tracks. Measure distance between any two points. USE YOUR PREFERRED UNITS Kilometers, Miles or Nautical Miles. Meters or Feet. Degrees, Degrees/Minutes, Degrees/Minutes/Seconds, UTM or NZTM2000 grid. °True or °Magnetic. HOW TOS Tap Help in the app. Online Manual: iSailGPS.com/nz Email developer: [email protected] RASTER CHARTS vs. VECTOR CHARTS The Land Information New Zealand Raster Nautical Charts in iSailGPS NZ differ from computer-drawn vector ENC charts in that each chart covers a specific area, the same way a paper nautical chart does. Switches automatically to a new chart when you leave the area covered by the previous chart. For many locations, there are multiple charts at different scales with different levels of detail & areas of coverage. Paper charts can contain multiple panels, each showing a different area or scale. Each digital panel is individually displayed by iSailGPS NZ with a north-up orientation. iSail GPS NZ is priced to make it readily available to all boating enthusiasts. iSailGPS NZ and the charts that it includes do NOT meet the legal requirements for navigation using charts that you may be required to carry. DEVICE REQUIREMENTS Use iSailGPS on any iOS device even if you don't have a cellular data plan for it. iPhones & WiFi+cellular iPads support all features. For WiFi-only iPads, an iOS-compatible external GPS receiver is required to show your location & record tracks. You can view charts using the iOS device alone. Discover a safer and more enjoyable sailing experience with iSailGPS NZ!

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

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.

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BUILD KIT DIFFICULTY
Advanced

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.