RichardS
N/A
My updated Navionics on Android also shows that anything more than 0.2 m draft will not get through that channel.
The access to the marina from the Mar Menor side is 2.6m
Is this incorrect? I've never been there.
Richard
Navionics charts - wrong, reliable, accurate?
- Thread starter concentrik
- Start date
My updated Navionics on Android also shows that anything more than 0.2 m draft will not get through that channel.
The access to the marina from the Mar Menor side is 2.6m
Is this incorrect? I've never been there.
Richard
concentrik
Well-Known Member
There are several hundred yachts and mobo's in Thomas Maestre marina who will be astonished to learn that according to Navionics they are landlocked!
It looks like the Navionics chart is just plain wrong, but apart from the immediate inconvenience to those hoping to get into the Mar Menor I feel there are further implications. The depth readings shown on the Navionics chart are precise to tenths of a metre; this precision implies accuracy which it appears is woefully absent. I wonder if the depth information for the area in question has been compiled using user data? Even if this is the reason it should have been apparent to Navionics that depths of 0,2M in a buoyed channel seem unlikely.
RichardS
N/A
Very strange ... I've been using the Android Navionics around Croatia and not found any signifcant errors but it's clearly way out here.
The sonar chart (user supplied depths) is no good as it looks from the chart as if no-one has ever sailed along that channel with their depth sounder on, even though there are plenty of user contours at either end of the channel.
There's even no user-added spot corrections as there seem to be everywhere else. Most of the user corrections are useless and I often turn them off but one or two would be very useful here. The marina have added their own data at the eastern end of the channel welcoming visitors and saying that they have fuel etc Although they don't mention the access depth, they point out that there is a minimum of 2m at the pontoons which would be a bit pointless if you couldn't get there.
My 2011 CM93 charts on OpenCPN show the minimum depth right in the centre of the channel as 1.3m but 2.4m and 1.6m just outside the channel at the same point. It looks like a channel which it is best to keep outside of!
Richard
RobbieW
Well-Known Member
It almost looks from the Navionics charts that the depth information comes from a time prior to the entrance channel and its surrounding structure being built. There is also a large semi-enclosed area on the seaward side of the entrance but within the walls that was supposed to be a marina (I think) that doesnt show on the charts. Its a safe enough anchorage though with a rather 'eastern european' feel given its surrounded by rusting metal piling.
A bit of fred drift, there was an interesting article on crowd sourced depth data on Panbo recently - http://www.panbo.com/archives/2015/...harts_for_garmin_conflict_messy_business.html. Great idea but I suspect commercial interests are blocking the sharing of data making each 'crowd' quite small.
JTulls
Member
On my app, I have the option to default back to the standard government charts, rather than the Navionics charts -- are those also incorrect for you? Also curious if you've upgraded to get access to the SonarCharts and if those depths are also wrong?
concentrik
Well-Known Member
JTulls: I wonder if you are referring to the NOAA Govt charts? We're not so lucky in the EU, we have to pay twice for govt charts! So I don't know about US chart accuracy, sorry. Yes I upgraded, yes it's still wrong.
I did have a couple of replies from Navionics, promptly and in detail to their credit. Whilst informative the reply didn't get to the crux of the matter for me - I only discovered the solution by research into their own Tablet test.
Firstly you need a tablet with at least 1280 pixels on the long side to render the maps well and I suspect the more pixels the better. 1040 tablets produce jaggies.
Secondly, the depths at Mar Menor entrance via the Tomas Maestre bridge were wrong and are still wrong in the mapset I downloaded yesterday. I will do as they suggest and report it.
Quote:=====================================================================
Thank you for contacting Navionics.
I will reply to your questions. I will try to be brief, but if you need additional information, do not hesitate to contact me again.
1) What you are reporting is not an error, but it happens due to the way our charts are made.
The Navionics Mobile apps are in vector chart format, which will display all text, depth soundings and chart objects at the same size at all zoom levels.
Since every device use a different screen resolution, the Navionics Mobile apps may be displayed differently on different devices.
2) The wrongly positioning could be due to a GPS issue.
In order to better understand what is causing this issue, please perform the following test for me:
- Go to the device’s “Settings” menu
- Go to “Location” and disable “Use Wireless Networks”
- Verify if the GPS is still working on the Google Maps App, and then using the Navionics app.
This will determine whether or not it is the GPS that is not working correctly, or the Navionics Mobile App.
The Navionics Mobile Apps will only use the GPS signal to determine location, and not the wireless network data.
3) The Navionics Mobile Apps are available for iOS, Android phones & tablets and Windows 8.1 tablets & PCs.
Even if the Chart displayed are the same, these Apps are all separated, and they have different features available.
4) The Navionics Apps offer you two chart layers:
The Navionics Charts information comes from multiple public and private sources, including government and Hydrographic Office charts, and our own survey data.
Navionics SonarCharts comes for other sources, and also our Community Sonar Logs. You can improve the accuracy of the charts for your favourite areas with your boat.
For more information, visit this page on our website: www.navionics.com/en/go-boating
Furthermore, if you fin out any discrepancies in our charts, please use this form: http://navionics.force.com/Mobile
This will send a report directly to our Cartography Department, and they will investigate and solve the issue for you.
And:
Please note, when talking about resolution and "smooth rendering", you should not consider only the screen resolution, or the screen size, but both these values.
The Asus Nexus 7, for example has a screen resolution of 1200x1920 pixels on a 7" screen. That means a pixel density of 323ppi (that is quite high).
A device with the same resolution on a 10" screen will have a lower pixel density, possibly resulting in a worse display quality.
Pixel density may on Tablets devices currently ranges from 350 ppi (better) down to 100ppi (worse).
On our website, you can consult the Compatibility Guide: http://www.navionics.com/en/compatibility
Navionics Boating Apps are designed to load and operate correctly with all Android devices with an Android OS 4.0 or higher.
The certified devices have been personally tested by our technicians and are guaranteed to be fully compatible with all our Apps.
The models not listed have not been tested by Navionics, but we expect the App to work correctly, and we are not aware of any compatibility issues with any device.
Furthermore, about the cartography issues, you should always check that yo have the latest, most updated charts with our WebApp.
You can find the WebApp on our website: http://webapp.navionics.com
It's a free online chart viewer, and has always the most updated charts.
If you need additional information, I remain at your service.
I did have a couple of replies from Navionics, promptly and in detail to their credit. Whilst informative the reply didn't get to the crux of the matter for me - I only discovered the solution by research into their own Tablet test.
Firstly you need a tablet with at least 1280 pixels on the long side to render the maps well and I suspect the more pixels the better. 1040 tablets produce jaggies.
Secondly, the depths at Mar Menor entrance via the Tomas Maestre bridge were wrong and are still wrong in the mapset I downloaded yesterday. I will do as they suggest and report it.
Quote:=====================================================================
Thank you for contacting Navionics.
I will reply to your questions. I will try to be brief, but if you need additional information, do not hesitate to contact me again.
1) What you are reporting is not an error, but it happens due to the way our charts are made.
The Navionics Mobile apps are in vector chart format, which will display all text, depth soundings and chart objects at the same size at all zoom levels.
Since every device use a different screen resolution, the Navionics Mobile apps may be displayed differently on different devices.
2) The wrongly positioning could be due to a GPS issue.
In order to better understand what is causing this issue, please perform the following test for me:
- Go to the device’s “Settings” menu
- Go to “Location” and disable “Use Wireless Networks”
- Verify if the GPS is still working on the Google Maps App, and then using the Navionics app.
This will determine whether or not it is the GPS that is not working correctly, or the Navionics Mobile App.
The Navionics Mobile Apps will only use the GPS signal to determine location, and not the wireless network data.
3) The Navionics Mobile Apps are available for iOS, Android phones & tablets and Windows 8.1 tablets & PCs.
Even if the Chart displayed are the same, these Apps are all separated, and they have different features available.
4) The Navionics Apps offer you two chart layers:
The Navionics Charts information comes from multiple public and private sources, including government and Hydrographic Office charts, and our own survey data.
Navionics SonarCharts comes for other sources, and also our Community Sonar Logs. You can improve the accuracy of the charts for your favourite areas with your boat.
For more information, visit this page on our website: www.navionics.com/en/go-boating
Furthermore, if you fin out any discrepancies in our charts, please use this form: http://navionics.force.com/Mobile
This will send a report directly to our Cartography Department, and they will investigate and solve the issue for you.
And:
Please note, when talking about resolution and "smooth rendering", you should not consider only the screen resolution, or the screen size, but both these values.
The Asus Nexus 7, for example has a screen resolution of 1200x1920 pixels on a 7" screen. That means a pixel density of 323ppi (that is quite high).
A device with the same resolution on a 10" screen will have a lower pixel density, possibly resulting in a worse display quality.
Pixel density may on Tablets devices currently ranges from 350 ppi (better) down to 100ppi (worse).
On our website, you can consult the Compatibility Guide: http://www.navionics.com/en/compatibility
Navionics Boating Apps are designed to load and operate correctly with all Android devices with an Android OS 4.0 or higher.
The certified devices have been personally tested by our technicians and are guaranteed to be fully compatible with all our Apps.
The models not listed have not been tested by Navionics, but we expect the App to work correctly, and we are not aware of any compatibility issues with any device.
Furthermore, about the cartography issues, you should always check that yo have the latest, most updated charts with our WebApp.
You can find the WebApp on our website: http://webapp.navionics.com
It's a free online chart viewer, and has always the most updated charts.
If you need additional information, I remain at your service.