Bodleian Library Map Room - Using VMAP Level 1 data in MapInfo

How to download and use VMAP LEVEL 1 Data in MapInfo

Vector Smart Map (VMAP) Level 1 is a global vector GIS dataset at 1:250 000 scale. This is currently the most detailed global digital dataset freely available and can be downloaded from the National Imagery and Mapping Agency (NiMA) website, using the GeoSpatial Engine The coverage is not complete - of the 234 zones which make up the dataset, only around 25% are currently (2002) available - others have not yet been completed or are not declassified. Coverage within tiles is not always consistent - data may be incomplete or missing altogether. Click here to see a sample of VMAP Level 1 data.

The most detailed data currently available in the Map Room is 1:1 000 000, so VMAP1 will provide a significantly higher level of detail. However it should only be used if a high level of detail is required - using it at scales smaller than 1:250 000 may result in far too much detail!

Current availabllity can easily be checked on the NIMA Geospatial Engine. The data is in Vector Product Format (VPF), which cannot be read directly by MapInfo, but the universal translator which is supplied with MapInfo can be used to translate the data into MapInfo .tab format.

Getting the data into MapInfo is a three-step process:

Check availability and download data tile(s)

Decompress data

Translate data into MapInfo .tab format

Check availability and download data

1. Go the the NIMA Geospatial Engine website

2. Click the link to the Geospatial Engine at the top of the Geospatial Engine information page

3. In the lower p[art of the Geospatial Engine page, click the NIMA Coverages tab, then click the checkbox to the left of VMAP1. Click Update map to show availability.

4. If it seems that the area you need is available, zoom in for more detail by selecting the Re-center and Zoom In option, then click once on the area of interest. The map will be redisplayed at a larger scale. Repeat this until you can see if the area required is definitely covered.
You can also use the World View-RegionalView-Local View settings to the right of the map to change the zoom level. You can also use the Find tab to search for a named location or enter coordinates if you prefer.
You can change the size of the preview map by clicking the Preferences tab and selecting a new size.

5. When you have located the area and coverage required, click the Download/Order tab.

6. Click the VMAP Level 1 in Mil-Spec option. The data will be G-zipped automatically.

7. Click Download to confirm and you will see the number of tiles (CDs) required and the file size.

8. Right-click the filename (xxxx.tar,gz) and the select Save link as... (If you need more than one tile then download and process each tile separately. Delete the unwanted file(s) before downloading the next tile. If you do not you may exceed the spare disk space on the PC!)

9. Save the file in in the C:\Temp folder. Make a note of the file name so you can find it again. After decompressing the data the original files can be deleted. The C:\Temp folder is cleared regularly so it is not necessary for you to delete them. When the file has been downloaded you can proceed to the next stage Decompress data. NOTE: The download process can be slow as files are usually over 100Mb.

Decompress data

The data is supplied in g-zip format. This has to be decompressed to extact the data. When the data you need has been translated into mapInfo format the downloaded file can then be deleted.

1. Files with a tar.gz extension are associated with WinZip. To extract the files, find the downloaded file by clicking the Start button then Programs>Drive C> Explorer. Go to the C\:Temp folder and double-click your downloaded tar.gz file. to launch WinZip.

2. When you are asked if the file should extracted to a temporary folder, click Yes. This is the first stage of decompression - getting the .tar file from the .tar.gz file. Extraction may take a while, so be patient! When extraction is complete you will see the entire contents of the .tar file - around 10, 000 files in some cases - but many of these are very small files.

3.When the .tar file has be decompressed, you will see a list of its contents. These are the vmap data files. These should be extracted into your own user folder and is best to create a new folder called vmap data for example. This will keep the files separate from any other files and when the required data has been translated into MapInfo tab format the entire folder and its contents can be deleted.
When the files appear in the list, click Actions on the menu bar and then click Select all (or use CTRL+A). This will highlight all the files.

4. Click the Extract button and in the Extract dialog, click the aroow button to the right of the Extract to box. In the Folders/Drives list find your user folder in the usrfldrs folder on Drive D. Click the New Folder button to create a new folder (call it vmap data for example). If you do not have a user folder, create one in the usrfldrs folder.

5. Click Extract to extract the files. This may take a while. When extraction is complete close WinZip

Translate data into MapInfo tab format

All steps are now performed in MapInfo.

MapInfo has a tool called Universal Translator, which translates a number of formats including vmap, into MapInfo tab format.

You should find this in the Tools menu in MapInfo.

If it is not there, click Tool Manager... then find it in the list of tools. Click the two checkboxes in Tool Manager then OK to add the tool:

The vmap data is arranged in coverages, each of which contains a number of layers. Not all layers may contain data, either because that particular feature does not appear on the tile area, or the data is missing. The coverages are:

Coverage	Description	Data types
bnd	boundaries, coast	point, line, area, text

elev	contours, depths and heights	point, line, text

hydro	rivers, lakes, dams, waterfalls etc	point, line, area, text

ind	industry, agriculture, nuclear, waste etc	point, line, area, text

phys	mountains, landforms, embankments, bluffs etc	point, line, area, text

pop	built-up areas, towns, villages, abandoned sites etc	point, line, area, text

trans	roads, railways, airports, ferries, bridges, harbours etc	point, line, area, text

util	power plants, pumping stations, pipelines etc	point, line, area, text

veg	land cover, oases, forests, firebreaks etc	point, line, area, text

placenam	place names	text

See the VMAP LEVEL 1 data layers list for the full listing of each coverage.

Translating a coverage

Each coverage has to be translated serataely, so you can choose which you need.

1. In the Universal Translator, you need to specify the source data format and file, and the destination.

2. Click the dropdown list and select Vector Product Format (VPF) In the Format box.

3. click the button to the right of the File(s) box and select a file. You will have to work down through several folders to find the coverages.

Point data files have a .pft extension, e.g: buildp.pft
Line data files have a .lft extension, e.g: landmrkl.lft
Area data files have an .aft extension, e.g: builtupa.aft
Text data files have a .tft extension, e.g: poptxt.tft

4. The projection has to be selected next. If you do not specify a projection, it will default to non-earth (i.e: without geographic coordinates) and cannot be used with other data. VMAP1 uses a geographic (lat/lon) projection, so in the Choose Projection dialog, select Longitude/Latitude in both the Category and Category members lists. Click OK to confirm.

5. For the Destination Format, select MapInfo TAB and choose a directory for the data. It is a good idea to create a new directory for translated data, as the original VMAP data can be deleted once all required layers have been translated.

6. Leave the Log to file and Append to Log checkboxes checked. If the translation fails, you can read this log to see what happened (usually a file is missing or corrupt).

7. Click OK to translate file. When translation is complete you can start another.

8. Check all your translated files are OK by opening then in MapInfo.

All data translates to the default style for that type, i.e: simple points, lines or polygons. You can change the style in MapInfo either permanently by editing the table, or by using Style Override. See the MapInfo guide for more information.

Nigel James
Map Room Bodleian Library 2002