Sunday, May 25, 2008

Cadastral Map
Cadastral maps deal with displaying a precise description of particular pieces of land. Generally names or numbers are assigned to each pand parcel which help identify the property. With these types of maps, the scale is crucial so accurate identification of the land is given.

Thematic Map

Thematic maps display spatial patterns between different attributes. Here is a Thematic map of Hawaii. The map can be qualitative or quantitative.

Here is a DOQQ(digital orthophoto quadrangle) map of Lake Travis conducted by the University of Texas at Austin, Texas. This was part of an attempt to help create a better floodplain map for Lake Travis and the surrounding area. A DOQQ map is a computer generated image of an aerial photo with geometric qualities of a map.

DRG maps are digital raster graphics. They are scanned images of a U.S. Geological Survey standard series topographic map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator projection. The map is scanned at a minimum resolution of 250 dots per inch.

DLG is also known as a Digital Line Graph. The example I posted is from Beaufort, South Carolina. It is a digital representation of the features displayed on a U.S. Geological Survey topographic map.

DEM is also known as a Digital Elevation Model. Here is a digital representation of the ground surface of Antarctica. They are usually made with remote sensing as opposed to direct surveying through the use of satellites.

Saturday, May 24, 2008

Planimetric Map
Planimetric maps display the horizontal position of planimetric features utilizing lines and symbols. They also use an X,Y coordinate system to help the person reading the map. They are great at accurately giving horizontal distances.

Black and White Aerial Photo

Here is a black and white aerial photo of Wrigley Field. This photo was taken by an airplane flying over the field. This field was built in 1914 and is one of the oldest fields in major league baseball. Black and white aerial photos give people a unique perspective at an area.

Wednesday, May 21, 2008


A Doppler Radar uses the Doppler effect of returned echoes from certain objects to measure their radial velocity. They are used for various things including air traffic control, police speed guns, and air defense. Here is a photograph from a Doppler Radar of Hurricane Andrew that hit Miami and caused extreme damage.

Mercator Projection
Gerardus Mercator developed this map in 1567. This was an excellent map for the sixteenth century and was used by sailors for navigation. The further lines of longitude remain parallel while the lines of latitude widen in distance as you move further from the equator. This causes the land masses in the poles to be exaggerated in size.

Saturday, May 17, 2008

Topographic Map- Crater Lake, Oregon

To the left is a topographic map of Crater Lake, Oregon. Here the map is using contour lines to show represent relief. This is used to show landscape variation in the area.