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Using Vector Maps with OziExplorer/OziMC

(Rev. Feb. 06, 2001)

If you're reading this webpage in search of how to upload topographic or other vector maps to your Lowrance/Eagle mapping GPS receiver, please be patient, as we need to lay some ground work before we get to the good stuff.  If you're here to learn about how to use vector maps with OziExplorer, most of what I'll present here, will be useful, but you can skip the stuff about OziMC. 
 

Step 1. Get the data.

There are 4 primary sources and 3 different types of vector map data for use with OziExplorer.  The first two types are the SDTS DLG and the DLG-O.  SDTS stands for Spatial Data Transfer Standard, or something like that.  It is the most commonly available format of free vector data for the U.S.  The USGS in an effort to encourage the use of SDTS, has made data for nearly the entire country, available for free. See http://mcmcweb.er.usgs.gov/status/100k/us_hp.html  ,for availability of topographic data, or http://mcmcweb.er.usgs.gov/status/100k/us_tr.html  , for availability of transportation (roads) data.  There are some areas of the country that are only available in the older DLG-O format.  Not to worry. Both SDTS and DLG-O formats are equally useable.  The third format is ESRI shapefile.  ESRI has available for free download, the Tiger95 data for the whole U.S., in shapefile format.  Tiger data is originally compiled by/for the census bureau and contains, detailed even if not so accurate street data, in addition to a wealth of demographic and environmental data.  ESRI also has data derived from the Defense Mapping Agency's, DCW (digital chart of the world), for free download.  Be forewarned, that neither the Tiger data, nor the DCW data is anywhere near as good as the real USGS DLG data.  The DCW data is of some use, for areas outside the U.S., since it does show some additional detail above and beyond what is typically contained in the basemap and or uploadable Worldmap of most GPS receivers.  If you have Lowrance City Streets (aka Marine and Recreation) CD, then there is no need to mess with the Tiger data at all, since you've already got it on the CD.  The USGS has compiled a large number of various maps as the National Atlas for the U.S. in both SDTS and shapefile format. 

http://www.gisdatadepot.com/catalog/US/sublist.html will take you to the GIS Data Depot, where you can choose the state that you're interested in and then further specify countywide data and which county you're looking for.  After that, you'll be presented with a list of different types of map data available for that county.  What we're after here, is the Hypsography 100K DLG (for topo) or Transportation 100K DLG (for roads etc).  Even more detailed data is available in the 24K hypso and transportation layers, but I recommend against going that route.  It's simply too much data.  The 100K data is plenty good for our purposes.  Once you've clicked on the hypso or transpo layer, you'll be taken to a page where you can select which quadrangle you want.  Unfortunately, you'll need to know the name of the quadrangle, as there is no graphical selection available.  If you happen to already have a 100K DRG of the area of interest, the name will be the same.  Usually a 60 minute by 30 minute 100K quad, will be divided into two 30 x 30 minute sections, an east and a west.  That page will usually incorrectly indicate that each area is available only in SDTS format, when in fact, both SDTS and DLG-O formats are available. After determining which one you want, ignore all that stuff about CD write fee and click on the greenish colored download button for that map, not the brownish colored button.  You're then taken to a page that will allow you to download the data itself, usually in the form of a ".GZ" file.  More on that later.  You'll be presented with many different files for download.  For topo (hypsography) data, the first 4 files are subsections of the east or west quad and are usually in DLG-O format with filenames like: 3_SJ3.HPF07.OPT.GZ.  All 4 subsections are usually available as a single file, in SDTS format, with a filename like: 5_SJ3.HYPSO.SDTS.TAR.GZ.  For transportation (roads, etc) data, there will be as many as 13 different files.  Not to worry, there will be 4 DLG-O format files, with names like 7932_SJ3.RDF03.OPT.GZ. The "RD" in the filename indicates that this is "roads" data.  "MT" is for mass transit data and "RR" is for railroad data.  As with the hypsography data, you can also download the whole thing, as a single file, in SDTS format, with a filename like: 2492_SJ3.TRANS.SDTS.TAR.GZ.  Right-click on the desired link as instructed and "save as" to do the download.  If that's all the data you want, then skip forward to step 2.  Otherwise hang around, for an alternative way to get the data you're looking for. 

Special note for Netscape and pre-5.0 version Internet Explorer users
When you go to do the "save as", in the preceding step, both Netscape and Internet Explorer versions prior to 5.0, will mangle the filename, by replacing "."s with "_" characters, except for the final "." preceding the "GZ".  Example: Suppose you're trying to download 5_SJ3.HYPSO.SDTS.TAR.GZ.  That will be changed to 5_SJ3_HYPSO_SDTS_TAR.GZ. You should change the filename back to the original, in the "save as" dialog box.  That will save some trouble later on.  Additionally, for Netscape users, if you attempt to download a DLG-O format file such as: 3_SJ3.HPF07.OPT.GZ from the Gis Data Depot site, not only will the "."s be changed to "_"s, the file will be automatically decompressed during download.  That would be ok, except that Netscape will erroneously tack on a ".GZ" extension, no matter what you attempt to name the file in the "save as" dialog box.  The only workaround is to rename the file after it finishes downloading.  In that case, renaming it to a DOS friendly 8.3 short filename with a ".DLG" extension (like SJ3HPF07.DLG), will save some trouble later on and you can skip the section on decompressing the data.  For SDTS format files, you still need to decompress the data.

http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/ndcdb.html will take you to the USGS Geographic Data Download page.  From there, click on the 1:100,000 DLG button.  You may now choose the "ftp via graphics" button.  This is much easier than the GIS Data Depot.  Just click away, until you've drilled down to the area of interest.  No need to know the quadrangle name at all.  Then choose which half you want, the east or west section and click on it.  You'll be sent to an ftp directory with several subdirectories.  If you want topographic data, click on the hypsography directory.  If you want road data, click on the transportation directory.  At that point, each half of the 100k quad is further subdivided into 4 or more DLG-O format files with filenames such as, 528298.HP.opt.gz, or you may also download all 4 subsections in one SDTS format file with a filename like: 1431464.HP.sdts.tar.gz.  Transportation data is subdivided even further, into railroad, mass transportation and roads data.  "Roads" data appears with filenames like: 528275.RD.opt.gz.  The "RD" indicates "roads" data.  If the filename shows a "MT", that's mass transit data and if it shows "RR", that's railroad data.  As with the hypsography data, the full data set is available as a single SDTS format file, with a name such as: 1431460.TR.sdts.tar.gz.  Select the file that you want, by right clicking and "save-as", to start the download.  See the preceding note for Netscape and pre-5.0 version Internet Explorer users if needed, but note that Netscape does not automatically decompress DLG-O format files downloaded from the USGS site, as it does from the GIS Data Depot site.

http://www.esri.com/data/online/tiger/index.html is the link to ESRI's free Tiger95 data in shapefile format.  http://www.esri.com/data/online/esri/wobmselect.html is a link to ESRI's free Worldmap data.  You will need to register to be able to download the data.  Once registered, click on the map to select the area you're interested in and click "submit".  You'll be taken to a long list of various layers available for download.  Most people will just want "Line Features Streets",  for the Tiger data, so tick that box and click on the "generate file now" button at the bottom of the page.  At that point you'll be taken to a page with a "download data now" button.  I'm sure that you'll be able to figure out what to do, from there.  If the only data you're interested in, is ESRI's shapefiles of Tiger95 data or Worldmap data, you can skip forward to the section on loading it into OziExplorer, after unzipping the file(s). 
 

http://www.nationalatlas.gov/atlasftp.html is the link to the National Atlas website, where you can download many many different maps of everything from butterfly populations to volcanoes, all in SDTS and shapefile format.  These maps may not be all that useful for uploading to a GPS receiver, but they may be interesting to some people for viewing with OziExplorer. 
 
 

Step 2. Decompress the data.

Now that you've got the data in ".GZ" compressed form, you need to decompress the file(s).  There are many different programs that can do this.  Usually there is not much to, doing the decompression, UNLESS YOU'RE USING WINZIP.  If you are, then you need to make one small change to the default WinZip configuration, to prevent corruption of the files during the decompression process.  In WinZip, choose options->configuration->miscellaneous and uncheck the box "TAR file smart CR/LF conversion".  After that, go ahead and open the ".GZ" file.  If you downloaded a DLG-O format file with a name something like, 531257_RR_opt.gz and you get a dialog box asking you to "Please enter the full name of the file contained within the archive .....", then name the file with a DOS friendly 8.3 filename with a "DLG" extension and see the section on Netscape and pre-5.0 version Internet Explorer, for future reference.  Whether you get the dialog box or not, go ahead and extract the file.  If you did not get a dialog box upon opening the ".GZ" file, you'll need to rename the extracted file to a DOS friendly 8.3 filename with a "DLG" extension.  If you did get the dialog box upon opening the ".GZ" file, you will already have taken care of the renaming.  If you downloaded a file such as 3_SJ3.HPF07.OPT.GZ, from the Gis Data Depot site, using Netscape and you attempt to open it with WinZip, you'll get an error message about the file being corrupted, or an invalid archive.  Simply rename the file to a DOS friendly 8.3 filename with a "DLG" extension and move on to the next section, as the file is already in decompressed form.  If you downloaded a file with a name like,  1432715_TR_sdts_tar.gz and you get a dialog box asking you to  "Please enter the full name of the file contained within the archive .....", then name the file anything you like, but use a ".tar" extension.  At that point, you'll get an additional dialog box asking "Should WinZip decompress it to a temporary folder and open it?".  Click yes and see the section on Netscape and pre-5.0 version Internet Explorer for future reference.    If you've made it this far, you're doing great.  Go ahead and extract the SDTS files.  There will be a whole slew of them.  Don't let that intimidate you.
 

Step 3.  Convert to mif format.

If you're working with SDTS DLG files you'll need a small DOS program called "sdts2mif.exe".  This program is available at  ftp://ftp.blm.gov/pub/gis/sdts/dlg/sdts2mif.exe .  If you're working with DLG-O format files, you'll need "dlg2mifx.exe" available as part of  dlg2mifx.zip.  In either case, the program must reside in the same directory as the SDTS or DLG-O files.

SDTS file conversion is accomplished by running sdts2mif.exe.  The program will ask you to input a 4 character base file name.  If you're translating road data, the correct 4 character base file name is "TR01".  If you're working with topo data, the correct name is "HP01".  You'll then be prompted to enter a base output filename.  Unless, you have some special reason, I recommend keeping the base output filename the same as the base input file name.  The program will then ask for the 2 digit suffix code.  For road data, there are basically 12 layers.  3 types x 4 subsections.  The 3 types are railroads, mass transit and roads.  The 4 subsections each correspond to 1/4 of the east or west half of the 100k quadrangle.  So, the 2 digit suffix code will range from 01 to 12.  01 thru 04 are for pipeline and powerline data.  05 thru 08 are for road data and 09 thru 12 are for railroad data.  For topo data, there is just one type, with 4 subsections.  So suffix codes range from 01 to 04.  After entering, the 2 digit suffix code, if you're working with road data, you'll get an error message about not being able to find file tr01ne01.ddf, or similar.  Just ignore it.  Conversion of topo data will not show that error message.  Sharp readers will probably want to jump ahead and try to load the ".MIF" file that we just created, into OziExplorer.  Although you can do that, you may want to see the next section on neatline removal. 

DLG-O file conversion is a little easier.  Execute the dlg2mifx.exe program, from the directory with the DLG-O file to convert.  It will prompt you for the name of the file to translate.  Be sure that you enter the "8.3" short filename and not the long filename.  You can skip step 4 on neatline removal, since the dlg2mifx program has already done that for you.
 

Step 4.  Neatline Removal (optional)

Skip ahead to step 5, if you converted DLG-O files to MIF format, in the preceding step.  Continue here, if you converted SDTS DLG files, in the preceding step.  Before we go removing the neatlines, you may want to know just what they are.  Simply put, neatlines are the border around the edge of the map data.  You will likely want to get rid of them, for use with OziExplorer, especially if you ultimately plan on uploading the map to your Eagle/Lowrance mapping GPS receiver.  Even if you're not going to upload, you may still wish to remove the neatlines, when using multiple vector maps with OziExplorer.  While technically, it is possible to edit out the neatlines using OziExplorer, there is an easier way.   The United Nations has a very nice little freeware program called "MapScan", that allows editing vector maps such as MIF and shapefiles.  MapScan can be gotten from http://www.undp.org/popin/softproj/download/mapscan/win/file/setup.exe  .  Once you've downloaded and installed MapScan, startup the program and select File => Open Vector. In the list of file types dropdown box, choose "*.mif - MAPINFO files". Navigate to the directory where you saved the MIF file and select it.  Once the map is loaded, maximize the map window and then select View => Full View, to see the whole map.  On the floating toolbar, click the delete segment button (the horizontal line with an "x" through it).  Next, click on each segment of the neatlines, one at a time.  The segments will be deleted, as you click on them.  You may need to zoom in, to be able to click on some of the really small neatline segments.  After zooming in, you need to re-select the "delete segment" button.  After deleting all the neatline segments, select File => Export Vector and a "Save As" dialog box will open.  Select *.shp ARCVIEW files, in the "Save file as type" dropdown box. You can save in *.mif-MapInfo files, but OziExplorer cannot read MIF format files written by MapScan.  You need to be careful here, since MapScan will let you specify a path and filename that does not conform to 8.3 short filename conventions, but it will fail when it goes to do the save, even if it is the very same directory that you opened the MIF file from.  So, make sure that the full path and filename, conform to 8.3 short filename convention.  This is a bug in MapScan, but not hard to work around, if you know about it. 
 

Step 5.  Loading MIF and shapefiles into OziExplorer.

You will need OziExplorer version 3.83h, as a minimum, to be able to import shapefiles.  For MIF files that started life as USGS SDTS or DLG-O files, you'll need OziExplorer version 3.85.4.  To work with OziMC, you should have OziExplorer version 3.85.1 as a minimum.  To import MIF files, startup OziExplorer and click on Map => Blank Map (Auto Scale).  Next click the "load" button and select Import => From MapInfo MIF Files.  Navigate to and select the MIF file that you want to import.  After the map loads, you may want to "Hide Points on Map", to remove the clutter from the display.

If you're working with shapefiles, after clicking on Map => Blank Map (Auto Scale), click the "load" button and select "Import ESRI Shape File".  Choose "polylines and polygons".  At this point, a small shape file import dialog box will appear.  Click on the "import" button and navigate to and select the shapefile that you wish to import.  Next, an options dialog will open.  If you're importing shapefiles that you have converted from SDTS or DLG-O format, then you need to select UTM for position format and NAD27 CONUS for datum.  Additionally, you'll need to specify the UTM zone and hemisphere.  At this point a shapefile attributes dialog will open.  Simply press the "continue" button, accepting "none" and "none".  The shapefile should appear on the screen.  Close the shape file import dialog. 

If you're working with the Tiger95 or other shapefiles that you got from ESRI, when you go to do the "Import ESRI Shape File", the correct datum is WGS84 and the position format should be set to Lat/Lon. 

If you don't own an Eagle or Lowrance Mapping GPS receiver, then you're done with this excruciatingly detailed treatise.  If you do own an Eagle or Lowrance mapping GPS receiver, then the fun has only begun. 

 

OziExplorer with topographic vector map loaded.
 

Step 6.  Using MIF and shapefiles with OziMC.

Here is what most of you have been waiting for.  Make sure that you've done step 5 above and save the track to a file, then press the OziMC button found on the toolbar.  The familiar OziMC feature edit box will open.  Choose which "Map Type" you wish to use.  It almost never makes sense to choose World Maps, due to the ~60 meter resolution of those maps.  Smart Maps have much better resolution, but are somewhat limited in what features are available for editing.  Choosing Ozi SM, gives a wide range of different feature types that can be edited.  This is especially important for those wanting to merge topo data into the Lowrance map database.  To do a merge of topo data, I recommend using the "OziSM Political Boundary" feature.  This feature appears as a dotted gray line on the GPS screen, so it won't obscure other important layers, in areas where the topo contours are especially dense.  Click on the feature that you wish to use and then click the "Edit" button.  After OziMC is finished compiling the feature, reload the track file that you had saved, by clicking on Load => Append Track from File and navigating to and selecting the file.  Once the previously saved track is loaded, click the "Save" button on the OziMC feature edit box.  After  OziMC is done saving the data into the feature, counterintuitively, click the "Cancel Edit" button.  The previously loaded "track", will now disappear from the screen.  Don't panic.  Simply double-click on the feature you were editing previously, to view the data that you merged into the database.  Close the OziMC edit box. 

 

Lowrance MapCreate with topo data merged from OziMC. 

Step 7.  Uploading the merged map to your Eagle/Lowrance GPS.

Not a whole lot to say here.  Open up Lowrance MapCreate, navigate to the area of interest and be sure that the feature that you edited using OziMC is turned on.  After that, define the polygon area that you wish to upload and proceed as usual, for uploading maps to the GPS. 


 

Final map after uploading to Lowrance GM100 (shown 2x normal size).
 

Email questions or comments to John Galvin

 

Related articles:

OziMC - A short review by a GPS Nut

Uploadable Maps Interface connector Active Antenna #1 Active Antenna #2 Hidden Keys Loose caps? MapFix NavAids System upgrades

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