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Archive for August, 2007

Downloadable Large-Format Historical Maps

There are a number of websites that have historic older maps available for online viewing (I’ll list a few of these in an upcoming post), but these sites typically don’t have the maps in high-resolution downloadable formats. You can always zoom in to the highest resolution, do a screen capture, then mosaic the images together if you have the time and patience. But there are a number of websites that do offer downloads of historic (and recent maps) in a high-resolution format. For some maps, a download link will be offered; for others, you’ll have to either right-click on a link to save the map to your computer, or open the image in your browser and then save it to your computer by right-clicking on the image.

Some maps are available in uncommon formats, like MRSid (*.sid), ECW (*.ecw) or JPEG2000 (*.jp2). If your graphics editor can’t open these formats, you can use the TatukGIS Viewer or IrfanView (with the additional plug-ins) to open these files and convert them to a more familiar format like TIF or JPG. Many maps are also available at the highest resolution in PDF format, and you can use a program like PDFCreator to convert them to standard image formats.

Library Of Congress: The US Library Of Congress has an enormous online collection of maps, historic and modern, for the US and the world, searchable and browsable by geographic area, keyword, subject, creator, and title. Most maps are downloadable in the MRSid format in very high resolution, but can also be viewed at various zoom levels online.

The Perry-Castaneda Map Library: Based at the University of Texas in Austin, this site offers modern and historical maps of the entire world at a wide variety of resolutions, mainly in JPG format but some in PDF as well. There’s also a large number of Texas maps (no surprise), and links to additional web map resources. I found the Army Map Service topographical maps of particular interest: 1:250K topo maps of many areas for which topo maps are difficult to find (Africa, Burma, Siberia, and more).

Leen Helmink: Website of a dealer in rare and antique maps, with high-resolution scans of historic maps from around the world, many for sale.

Yale University Map Library: A number of their historical and current maps are available for download in the JPEG2000 format (with more being added all the time).

historic map of Africa

Africa map from Yale collection (resized 10x smaller than the original in pixel dimensions, 100x smaller in pixel area)

University Of Connecticut: Many historic maps, primarily of the New England and Mid-Atlantic region, most both viewable online and downloadable in MRSid format.

The Atlas Of Canada: Modern and historic maps of Canada, many (but not all) downloadable in JPG and PDF formats; check the bottom of the individual map pages to see if there are download links available. PDF maps are usually of higher quality than JPG.

Michigan State University: Primarily maps of Michigan, but some maps of Africa and North America.

Quebec National Library And Archives: In French, but you should be able to get around. Mainly maps of Canada and North America, browsable by titles (“titres”), authors (“autheurs”), by time (“chronologique”) and area (“toponyme”). Look for the link titled “la carte agrandie” to open the map image at full resolution in a new window, then right-click on the image to save it.

W. M. Keck Earth Sciences and Mining Research Information Center: Large selection of historic and modern maps of Nevada and surrounding areas.

Know of a good site that I’ve missed? Post it in the comments, and I’ll do a follow-up post later.




Determining Google Earth Path Lengths

One of the quirks of Google Earth is that while you can draw a path between points as a feature using the “Add Path” toolbar button, or measure the individual and combined distances between points using the ruler (click on the “Show Ruler” button, then the “Path” tab), there’s no automatic way in Google Earth to determine the length of a path drawn using the “Add Path” button, short of tracing over it with the ruler. But there are several utilities that can take the KML file of a path and convert it into a distance. Two of them require you to to copy the KML path data into the clipboard (right-click on the path, and choose “Copy”), then paste it into the application. The third will accept data that way, but can also open a saved KML file to do the calculation.

Continue reading ‘Determining Google Earth Path Lengths’




Labeling Geotagged Photos With Coordinates and Time

4/26/09: GPStamper is now a commercial program; there’s a trial version that runs for 30 days, and free versions are available for non-commercial scientific work and surveys.

Geotagging a photo embeds geographic coordinates into the EXIF header, where it joins other information like the date and time the photo was taken. In a sense, Mike Lee’s GPStamper program does the opposite: it extracts the geographic coordinates from a geotagged photo, and makes a lossless copy of the photo with the geographic coordinates (and optionally the date and time) printed in yellow in the lower-right-hand corner of the photo.

Download GPStamper here, and install the program. You’ll also need to download EXIFTool for Windows, change the name of the exiftool(-k).exe file to exiftool.exe, and put it into the GPStamper program directory. Run the program:

GPStamper

Step 1 is to press the “Folder” button, and select a folder with geocoded photos in it. Then click on “PREPARE”, and the program will “prep” the EXIF header of the image files for stamping. Images are backed up automatically as a precaution; the backup has “_original” appended to the .JPG file extension, e.g. the original file “picture.jpg” will now be named “picture.jpg_original”.

Step 2, press the “File” button to select a photo to label with the coordinates, coordinates /date, or coordinates/date/time, depending on which of the options are chosen at the right. GPStamper doesn’t do batch labeling – you have to do one picture file at a time. When you press the “STAMP” button, GPStamper takes the JPG file and labels it as specified, leaving the rest of the image untouched and undegraded. It then saves the labeled photo with “-gps” appended to the filename, leaving the original as-is. So, for example, the original geocoded picture below, DSC00030.jpg …

DSC00030

… is labeled with coordinates/date/time in the lower right-hand corner, and saved as DSC00030-gps.jpg …

DSC00030-gps

… but with the quality of the original image unaffected.

Mike has made the user interface as simple as possible, but welcomes user feedback on both the interface and the features. He also has a number of other useful image tools on his Lossless JPEG Toolbox website.

Edited 8/28/07 to indicate change in program: backing up original image files was originally an option, but is now done automatically by default.




FlashEarth In Google Earth

A clever hack for the new version of Google Earth from Valery Hronusov and Barry Hunter of nearby.uk.org. Using the new capability of Google Earth to embed Flash into placemark bubbles, there’s now a KML network link at nearby.uk.org. Open it in Google Earth, and a white arrow will appear in the center of the screen. Click on the arrow, and a bubble will pop up giving you the choice of imagery for that area from a number of different online mapping sites (e.g. Google Maps, Yahoo Maps, Virtual Earth) using Flash Earth:

flash

Requires the latest version of Google Earth running in Windows (GE for Mac and Linux doesn’t support embedded Flash yet).

Via Google Earth Blog.




Digipoint 2: Export Of Google Maps Points In Multiple Formats, And Elevation Data

Quite a while ago, I posted about Digipoint, a website that let you plot points in Google Maps automatically get the coordinates of the points, and export the data in text (TXT), AutoCad (DXF), comma-separated values (CSV), BLN (Golden Software blanking format) and tab-delimited (TAB). The Digipoint website has been upgraded to version 2 since then, enhancing the old features and adding new ones:

  • Export in KML, GPX, and shapefile formats has been added to the previous export options listed above
  • Selectable icon shapes and sizes (Small, median, normal and big); click on the icon image to change the icon shape, choose the size from the drop-down next to it
  • Four map-click options:
    • Add point
    • Delete point (new)
    • Edit label (new)
    • View elevation (new) – click on a point on the map and get the elevation
  • Check the elevation box, and as you add points to your list, the elevation will be added as well
  • An instantaneous readout of the cursor coordinates as you move it over the map display
  • A separate “Options” button to set coordinate systems (lat/long. or UTM) and elevation units (meters/feet)

Digipoint2




Horizon Terrain Profiles In Google Sky

The creators of HeyWhatsThat, a site that generates panoramas and viewsheds for Google Maps and Google Earth and described in an earlier post, have added another cool feature. Generate a panorama, click on the “View in Google Earth … at night” link, have it open in Google Earth in Sky mode, and the horizon line will be plotted against the sky for the specified location, labeling each of the features. Lots of good stuff at the HeyWhatsThat site!

horizon




Stand-Alone Map Projection Viewers III – MicroDEM

In addition to its primary terrain analysis functions, MicroDEM also has a number of map projection viewing features, accessible by opening a vector map from the File => Open => Vector Map menu, or clicking on the “Open vector map” button on the top toolbar:

vector

This brings up the “Map Projections” window:

Continue reading ‘Stand-Alone Map Projection Viewers III – MicroDEM’




A KML To CSV (And CSV To KML) Converter For Spreadsheets And Garmin POI Files

Newer Garmin GPS units support the upload of sets of POIs, containing both position data and descriptions of the Points Of Interest. The KMLCSV Converter is a Java application that lets you convert placemarks created in Google Earth and saved as a KML file into a CSV (Comma-Separated Values) file compatible with Garmin’s POI Loader; this CSV would also be compatible with most spreadsheet programs as well. The process is straightforward:

1. Create placemarks in Google Earth using the “Add Placemark” tool, search, or other means.

2. Add a description to the placemark.

3. Drag all the placemarks you want to save into a single folder.

4. Save the folder as a KML file

5. Convert it to a CSV file with the KMLCSV Converter Program (screenshot from website)

screenshotkmlcsv

6. Upload the CSV POI file to your Garmin with the POI Loader program, or into your spreadsheet as a standard CSV file.

There’s a short PDF tutorial file that covers these steps quite clearly with screenshots.

You can also convert CSV files, either POI files or spreadsheet files created by yourself or someone else, into KML files for viewing in Google Earth; a search for “Garmin POI” files on the web will bring up links to many sources, both free and paid. But I prefer the program csv2kml for that purpose.