How to create a population map of the US using QGIS

You can create a map of the US showing the population intervals by county.

You can do this by using a free GIS desktop program called QGIS and free GIS data available on various websites.

Download the Census shapefile from the census.gov website here. It should be called ‘County_2010Census_DP1′.

Open the QGIS program and go to the ‘layer’ menu and select ‘add vector layer’. Navigate to the ‘County_2010Census_DP1′ zip file and add it to your map. Alternatively the zip file can be dragged and dropped into the map window. It should appear as below.

counties_screenshot

If you right click the layer item on the left and go to ‘open attribute table’ you will see the county names and various population figures in the table.

table_screenshot

In the census zip file there is a file called ‘DP_TableDescriptions’ which explains the column headings of the tables.  The column called ‘DP0010001′ is the column containing total population figures. We will use this column to graduate the colors of the counties according to their population value.

Double click the layer ‘County_2010Census_DP1′ so the layer properties windows appears as shown below.

style_screenshot

Change from single symbol to graduated and then below that select the column ‘DP0010001′. Under Mode change it to Quantile (equal count) and press OK. The map should as shown below.

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You can create a printable map, add a frame, legend, north point etc. by following the instructions on this page.

Calculating slope from contours using buffers and creating a slope map

Here is a simple way of creating a slope map using contour data to create a vector polygon layer.

Below we have 50m contour data.

contours only

For example to calculate a slope of 10 degrees or greater using 50m contours we must calculate the maximum distance between contour lines that results in a 10 degree slope using a trigonometric equation.

10 degree slope

In this example the maximum distance is 284 meters between the 50m contour lines.

We then halve this distance to get 142 meters and use this value to buffer the contours. Do not dissolve the buffer results as we will need to find the intersects between the buffers.

contours buffered

Intersect the buffers to find the overlapping areas. The intersect tool in ArcGIS can be useful for this. These overlaps will signal the contours lines that have 10 degrees or more slope between them.

intersected buffers

These intersected slithers only represent part of the 10 degree slope as the 10 degree slope should in theory cover the entire width between the two contour lines and possibly beyond the contour lines depending on the width of the intersect.

Buffering these intersects using the 142m figure that was calculated previously will extend the slope areas to the nearest contour line and beyond depending on the steepness of the slope. Dissolving this final buffer will create a single feature representing the 10 degrees and above slope.

calculating slope from contours

To calculate slope intervals, you would follow the same process as above with progressively higher slopes while clipping out the lower slope layer with the higher layer until you reach the largest slope interval layer. 

 

 

 

 

Earthquake Epicenter off the Coast of Northern Japan 2011

Japan Earthquake 2011 Epicenter

A large earthquake, measured at 8.9 on the Richter scale hit earlier today off the coast of Japan near the city of Sendai, Miyage Prefecture. As a result a tsunami devasted buildings and farms in the Northern prefecture and the number of casualties is not quite known yet.

Tremors in Tokyo were also felt stopping train lines both above and underground causing many citizens to stay overnight at their workplace.

Yakushima Island Japan


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Here is a map of Yakushima Island. It is a natural World Heritage Site since 1993. It is famous for its ancient trees known as Sugi in Japanese, often called Japanese cedar trees. This species of tree is endemic to Japan and some trees are said to be thousands of years old.

It is also a habitat for deer, macaque monkeys and migratory sea turtles and was the inspiration for Hayao Miyazaki’s animation Princess Mononoke. There is mountainous terrain on the island with the highest point reaching 1,935 meters above sea level. It is the southern most part of Japan where snow falls in the mountains. However the ocean temperature is never under 19 degrees Celsius and frequent rainfall causes humid conditions in spring and summer.

China’s Yangtze and Yellow River Map

china_river

The Yangtze River is the longest river in Asia and the third longest in the world behind the Nile and the Amazon river. It is estimated to be about 6300 km or 3915 miles long. It originates from a glacier located on the eastern side of the Plateau of Tibet.

The Yangtze is heavily polluted due to untreated wastewater discharged into the river. Wildlife like the local population of dolphins has become threatened. Moreover the quality of drinking water for the population living along the river has become degraded.

The Yellow River is the second longest river in China and is approximately 5,464 kilometers or 3,398 miles in length. It has been dubbed the ‘cradle of Chinese civilization’ as it is believed that China’s civilization originated from here.

It also has been nicknamed ‘China’s pride’ as well as ‘China’s sorrow’ as the river is prone to severe floods due to its elevated river bed. The name the ‘Yellow River’ comes from the ochre-yellow color of the river in the lower course of the year. This color is caused by the amount of sediment that is suspended in the waters.

The Yellow River is very polluted mainly due to discharge from industry and household wastewater. Currently it has been estimated that one third of the river is unsuable even for industrial or agricultural use.

Japan’s Mountainous Areas Map

japan-mountains

Here’s a map of Japan that I created. It shows the mountainous area of the island nation and as indicated on the map the majority of the land is mountainous and therefore difficult for residential, industrial or agricultural uses.

It is estimated to be about 145,883 square miles in size with 70 to 80% being mountainous. The mountainous areas are usually covered in forest.

Difficulties in traveling across the country have been overcome by technological advances, as Japan is famous for its long railway tunnels that go under the hills and mountains.

Because of Japan’s location at the intersection of three tectonic plates, earthquakes are commonplace. In addition to this, 10% of the world’s active vocanos are found in Japan. The most famous of Japan’s volcanos is mount Fuji, located between Tokyo and Shizuoka, which is still considered active. In the cooler seasons, steam can be seen bellowing out of the top of Mount Fuji.

Sonoran Desert Map

Maps.com has your San Diego Maps!

sonoran_desert

Here’s a map of the Sonoran desert that I created.

The Sonoran desert is one of the largest and hottest deserts in North America. It is about 120,000 square miles in size. Despite the harsh conditions the thriving city of Phoenix is located in this desert. Phoenix has a population of over 4 million and is one of the fastest growing cities in the US. The desert is actually losing ground to the urban sprawl around Phoenix.

The Sonoran desert is home to an assortment of cactus species including the famous saguaro cactus, pictured below, which is found only in the Sonoran. There is also a diverse range of animals including the bobcat, coyote, antelope and various reptile species.

cactus

cc photo credit: SearchNetMedia


Baja California Satellite Maps

Perth Australia Tourist Map – Things to do

Perth_tourist_map

Here is a map of Perth, Western Australia I created. It shows the main attractions around the Perth metropolitan area. I have included the spots that I believe are a must-see. I have lived in Perth for over 25 years and I have been to each of these locations, some of them numerous times. I highly recommend each of these sightseeing spots, each for their natural beauty and historical significance.

1. Rottnest is an island located about 20km from Fremantle. It is famous for its crystal clear blue waters and a small animal called a quokka.

The quokka is a marsupial, similar to a kangaroo but much smaller. It is found only on the island of Rottnest. They are friendly to tourists and are numerous on the island.

Snorkeling is a must do activity as the waters a very clear, and beautiful coral and fish can be seen.

Rottnest is small enough to ride a bicycle around in a few hours. This is a great way to see the entire island especially its famous salt lakes and coastline. Bikes can be rented for a day at various bike hire venders.

2. Kings Park is located right near the Perth city center. It is located on top of a hill overlooking the city providing a spectacular view of the city and the Swan river.

Within the park, visitors can use the BBQ facilities for free nearby ponds and giant native Western Australian trees. Swimming in the ponds are the famous black swans, the symbol of Western Australia.

There are also many war memorials in the park for those interested in Australian war history.

3. Fremantle is the port city of Perth. Here many historical buildings and museums can be found. I’d recommend seeing the Maritime museum, Fremantle markets and the Fremantle prison.

Fremantle is also famous for its large Italian community and it offers many restaurants and cafes. Tourists can relax and enjoy the pleasant weather in Fremantle’s city center by dining outdoor at one of these cafes or restaurants.

Ferries to Rottnest Island can be caught from Fremantle.

4. Scarborough and Cottesloe beaches are the two most popular beaches in Perth for locals and tourists. In the hot months, December to March people flock to these beaches to enjoy the cool, clean waters.

Scarborough beach is known for its large waves and so it is great for body boarding and surfing. Cottesloe is a favorite place for swimmers or people who want to work on their tan on the white sands.

5. Penguin Island is a small island near the town of Rockingham. As its name suggests, it is the home of the world’s smallest penguins. Dolphins can also be seen around the island. Ferries leave hourly from Rockingham.

6. John Forrest National Park is located 26 kilometers from Perth city in the hills overlooking Perth. Here large native trees can be seen including the Jarrah, Wandoo and Marri species. The clay soil is a red color in contrast to the white sandy soils of the coastal area.

Kangaroos, Echidnas (similar to a hedgehog), Short-Nosed Bandicoots, and Wallabies can sometimes be seen in their natural habitat.

I’d recommend seeing this national park to experience the natural environment that is abundant in the South West of Western Australia.

7. The Swan Valley is an area most famous for its wine growing industry. High quality wines such as Houghton and Sandalford are produced here. Visitors can try wine tasting and enjoy the scenic natural beauty that the Swan valley has to offer.

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