Guest Posted October 10, 2010 Share Posted October 10, 2010 Tuffy be careful using the LINZ image charts as they aren't quite corrected - i.e. if you piece them together they don't quite match up and you can get some errors. No matter in the middle of the gulf but not flash at 2am zoomed right in trying to find a tight anchorage near anything rocky..... EE Link to post Share on other sites
rigger 47 Posted October 10, 2010 Share Posted October 10, 2010 If you have the software that can load / use RNC format LINZ has them for free. NZMariner is the product name of New Zealand's Official RNC folio, and is available for download at no charge from this page. LINZ publishes NZMariner plus a monthly cumulative update file of corrections published in Notices to Mariners. NZMariner can only be used in conjunction with compatible viewing software: Electronic Charting Systems (ECS) or Electronic Chart Display Information Systems (ECDIS). http://www.linz.govt.nz/hydro/charts/di ... index.aspx Link to post Share on other sites
tuffyluffy 76 Posted October 10, 2010 Share Posted October 10, 2010 tuffyluffy your setup looks interesting at that cost. What do you use for your gps input and laptop comms? Cheers Cathy Hey Cathy, Ive got a permanently mounted GPS antenna on the pullpit with the cable run to the Nav station. It has a USB plug on it which slots into the laptop. I cant remember where i got it but if you google 'GPS antenna USB' you should find several options. EE, so far i havent had any issues using the LINZ charts. Id never rely 100% on the accuracy of any plotter to less than 50m. What werer you using to calibrate the images? Seaclear? Link to post Share on other sites
tuffyluffy 76 Posted October 10, 2010 Share Posted October 10, 2010 If you have the software that can load / use RNC format LINZ has them for free. NZMariner is the product name of New Zealand's Official RNC folio, and is available for download at no charge from this page. LINZ publishes NZMariner plus a monthly cumulative update file of corrections published in Notices to Mariners. NZMariner can only be used in conjunction with compatible viewing software: Electronic Charting Systems (ECS) or Electronic Chart Display Information Systems (ECDIS). http://www.linz.govt.nz/hydro/charts/di ... index.aspx Does anyone know which software uses that format? Link to post Share on other sites
Guest Posted October 10, 2010 Share Posted October 10, 2010 There is a list of companies that have permits to use the software in the technical documents page on the linked website navigation toolbar. They will probably be for purchase only I would guess. Are these charts legal for commercial navigation purposes being in raster format not Vector? It says they conform to ECDIS, so they must be I guess. Link to post Share on other sites
rigger 47 Posted October 11, 2010 Share Posted October 11, 2010 There is a list of companies that have permits to use the software in the technical documents page on the linked website navigation toolbar. They will probably be for purchase only I would guess. Are these charts legal for commercial navigation purposes being in raster format not Vector? It says they conform to ECDIS, so they must be I guess. You would still need vector charts if available to dump the paper charts. Link to post Share on other sites
Guest Posted October 11, 2010 Share Posted October 11, 2010 Tuffy - we tried a number of chart viewers while in the process of developing our own with a software super-geek I know about 12 months ago and it was the same discrepancy on all of them with the LINZ image files. Long and short of it we gave up and moved on. Its not just when looking for an anchorage - another good example would be threading the Whale Rock needle in coastal a la a certain yacht in last years coastal - times like that you really need confidence in what you are looking at. Cheers EE Link to post Share on other sites
wheels 543 Posted October 11, 2010 Share Posted October 11, 2010 Mate! I wouldn't have confidence in the accuracy of the GPS, let alone the chart. Link to post Share on other sites
Guest Posted October 11, 2010 Share Posted October 11, 2010 likewise Wheels - its still only a guide to be used in conjunction with a bit of common sense and dead reckoning based on what else you can see. However it is very handy in validating the same. I generally get 12 Sats and supposed accuracy down to 3m on my Garmin 60CSX which has a pretty flash chipset in it for its size. EE Link to post Share on other sites
wheels 543 Posted October 11, 2010 Share Posted October 11, 2010 I was watching my GPS the other day, and I had locked onto quite a few sats. But the postion was jumping all over the place. So I was certainly getting lots of errors in the signal somehow. I also reckon now, that when we tried out for lighthouse keepers at out D-Urville, that the chart itself is actually shifted across somehow. But a considerable distance, like 10 to maybe even 20m. So the GPS may have told me I was at X, and X was possibly correct, but the chart itself was offset at X. Because after reviewing my track out there, the entire chart seems to be over to far to the East. It is possible the GPS track is out, but I would expect to see errors in the track and not a dead straight line. Maybe I am wrong there with how it all works. Link to post Share on other sites
Guest Posted October 11, 2010 Share Posted October 11, 2010 I think Wheels is referring to using a USB GPS aerial and downloaded scans of LINZ charts. I guess once you have it up and running as Tuffy does there would be alot of checking going on until you are comfortable with the accuracy. Those free LINZ charts that can be calibrated to be used with Seaclear don't appear to have updates either, so how old are they? The ones linked above have the monthly update available to be downloaded, but you need to pay for a software setup to get them running. One of the websites listed as having compatible software were quoting 150 pounds to buy, which isn't too bad for something that has been certified to work properly, and can use the latest charts for free. If you buy a dedicated chartplotter with vector charts installed, the functionality is far superior though. Being able to turn on/off stuff you don't want to see, and the ability to go course up on the plotter and the writing doesn't go upside down like a raster chart is nice too! Just read Wheels post that he's done in the meantime and he's seeing far bigger problems than I assumed. Link to post Share on other sites
wheels 543 Posted October 11, 2010 Share Posted October 11, 2010 Often the case, I always seem to be a far biger problem than most assumed. I have the Navman 5600 GPS with full NZ chart. Oh and I had a chuckle looking at an add for a GPS unit that had 50 channels. Umm....Why???The only time you might see every Sat up there is when you are on a trip to the Sun. And even then there ain't anywhere near 50 of them. Link to post Share on other sites
tuffyluffy 76 Posted October 11, 2010 Share Posted October 11, 2010 I spent approx a week with the ariel on the dash of the car and the lappy on the passenger seat driving around Akl, and especially over bridges that are marked on the charts, and the acurracy was spot on (well within a few metres). It even pickup up a lane change to overtake an Asian doing 80 in the fast lane on the Pakuranga Bridge (ops, i think i just did a Paul Henry). I was pretty impressed with it. The GPS ariel i bought wasnt cheap, in fact, it was the most expensive part. Its what they refer to as a 'Active' GPS antenna, not your el-cheapo variety. All in all, its as accurate as i need and i can load freebee charts for anywhere in the world, and thats what i wanted. I cant stand proprietry software and image formats. Link to post Share on other sites
PaulR 3 Posted October 11, 2010 Share Posted October 11, 2010 Calibration: In my Memory-Map PC system, I have just downloaded the TIFF LINZ charts for the Coastal Classic and they all had the latest NtoM corrections. Admittedly I use it for planning at home. When calibrating I use the top-right and bottom-left corners + another corner and all is OK. I then use the 4th corner, often finding a little difference, and then plot another four to six more positions, nearer the land on the chart. These extra positions IMPROVE the overall calibration accuracy, especially when they are nearer the dangerous solid land stuff. Perhaps wheels, you may need extra calibration points spread across the chart. The Mercator projection is not perfect and coupled with electrical inteference(s), the onboard GPS systems are a great aid, but a good lookout requires no power source! FYI I have had good results with ATL's Seiwa inbuilt GPS aerials. One less external connection to worry about. It even works down below on 4 different yachts. Link to post Share on other sites
PaulR 3 Posted October 11, 2010 Share Posted October 11, 2010 I agree with tuffy. Driving around Westhaven car parks in the pouring rain, we were able to practise the "man overboard" function and is was very accurate. Stayed dry too Link to post Share on other sites
SloopJohnB 323 Posted October 12, 2010 Share Posted October 12, 2010 , the entire chart seems to be over to far to the East. . The whole South Island shifted sidewards 5 weeks ago. Link to post Share on other sites
wheels 543 Posted October 12, 2010 Share Posted October 12, 2010 That's the way to do it. Can't sort out accuracy with the machine, lets move the whole darn country. Of course, it could have gone the wrong way and I am twice as far out now. Within the sounds, the accuracy has been spot on. Or was of course. Link to post Share on other sites
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