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Basalt: A fine-grained igneous rock that is usually black in color. The specimen shown is about two inches (five centimeters) across.

What is Basalt?

1. The Raw Image Extension adds native viewing support for images captured in raw file formats produced by many mid- to high-end digital cameras. By installing the package, you will be able to view thumbnails and metadata of supported raw file formats right in Windows File Explorer or view images in the Photos app.
2. How to add new hotspot to the image. Add new hotspot and it will appear at the center of the image 2. Type tooltip text in the description field 3. When you hover over the image you can see the x and y percentage position of the cursor at he top right hand corner 4. Just put a cursor to the place where you want to add a pointer, remember the.
3. An image map allows you to define hotspots on an image that acts just like a hyperlink. The basic idea behind creating image map is to provide an easy way of linking various parts of an image without dividing it into separate image files. For example, a map of the world may have each country hyperlinked to further information about that country.

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Basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in small intrusive bodies, such as an igneous dike or a thin sill. It has a composition similar to gabbro. The difference between basalt and gabbro is that basalt is a fine-grained rock while gabbro is a coarse-grained rock.

Olympus Mons Volcano: This shield volcano is composed of basalt and has enormous calderas at the summit. Olympus Mons is the highest topographic feature on Mars and is the largest known volcano in our solar system. It is about 375 miles (600 kilometers) in diameter and 15 miles (25 kilometers) high. NASA Mars Orbiter Camera image.

Earth's Most Abundant Bedrock

Basalt underlies more of Earth's surface than any other rock type. Most areas within Earth's ocean basins are underlain by basalt. Although basalt is much less common on continents, lava flows and flood basalts underlie several percent of Earth's land surface. Basalt is a very important rock.

Basalt on Moon and Mars

Basalt is also an abundant rock on the Moon. Much of the Moon's surface is underlain by basaltic lava flows and flood basalts. These areas of the Moon are known as 'lunar maria.' Large areas of the Moon have been resurfaced by extensive basalt flows which may have been triggered by major impact events. The ages of lunar maria can be estimated by observing the density of impact craters on their surface. Younger basalt flows will have fewer craters.

Olympus Mons is a shield volcano on Mars. It, like most other volcanic features on Mars, was formed from basaltic lava flows. It is the highest mountain on Mars and is the largest known volcano in our solar system.

Basalt-Forming Environments: This map shows the location of oceanic divergent boundaries and hotspots. These are locations where large volumes of basalt have been formed. Map copyright by Geology.com and MapResources. Locations generalized after United States Geological Survey, Geologic Investigations Map I-2800: This Dynamic Planet.

Igneous rock composition chart: This chart shows that basalt is typically composed of pyroxenes, plagioclase, micas, and amphiboles.

Basalt-Forming Environments

Most of the basalt found on Earth was produced in just three rock-forming environments: 1) oceanic divergent boundaries, 2) oceanic hotspots, and 3) mantle plumes and hotspots beneath continents. The images on this page feature some of these basalt-forming environments.

Sea floor pillow basalts on the Juan de Fuca Ridge, a divergent plate boundary located about 150 miles (240 kilometers) west of the Washington-Oregon coast. This lava flow, produced by a fissure eruption, was about five years old when the photograph was taken. NOAA Ocean Explorer image.

Hawaii Basalt Flows: Lava flows dump into the Pacific Ocean on the coast of Hawaii. Multiple locations where hot lava streams into the ocean can be seen in this image along with a red-hot lava flow traversing the lava field. This photo shows the enormous extent of the flows. They extend from the shoreline up to the horizon. A volcanic plume from the Pu`u `O`o vent can be seen over the horizon near the center of the image. The lava in these flows originated from the Pu`u `O`o vent. USGS image.

Basalts at Oceanic Divergent Boundaries

Most of Earth's basalt is produced at divergent plate boundaries on the mid-ocean ridge system (see map). Here convection currents deliver hot rock from deep in the mantle. This hot rock melts as the divergent boundary pulls apart, and the molten rock erupts onto the sea floor. These submarine fissure eruptions often produce pillow basalts as shown in the image on this page.

The active mid-ocean ridges host repeated fissure eruptions. Most of this activity is unnoticed because these boundaries are under great depths of water. At these deep locations, any steam, ash, or gas produced is absorbed by the water column and does not reach the surface. Earthquake activity is the only signal to humans that many of these deep ocean ridge eruptions provide. However, Iceland is a location where a mid-ocean ridge has been lifted above sea level. There, people can directly observe this volcanic activity.

Thermal image of a hot basalt flow on the flank of Hawaii's Kilauea volcano. Hot lava at the front of the flow is revealed in yellow, orange and red colors. The channel that it flowed through on the previous day appears as a purple and blue track. United States Geological Survey image.

Oceanic Hotspots

Another location where significant amounts of basalt are produced is above oceanic hotspots. These are locations (see map above) where a small plume of hot rock rises up through the mantle from a hotspot on Earth's core. The Hawaiian Islands are an example of where basaltic volcanoes have been built above an oceanic hotspot.

Basalt production at these locations begins with an eruption on the ocean floor. If the hotspot is sustained, repeated eruptions can build the volcanic cone larger and larger until it becomes high enough to become an island. All of the islands in the Hawaiian Island chain were built up from basalt eruptions on the sea floor.

The island that we know today as 'Hawaii' is thought to be between 300,000 and 600,000 years old. It began as an eruption on the floor of the Pacific Ocean. The volcanic cone grew as recurrent eruptions built up layer after layer of basalt flows. About 100,000 years ago it is thought to have grown tall enough to emerge from the ocean as an island.

Today it consists of five overlapping volcanoes. Kilauea is the most active of these volcanoes. It has been in amost continuous eruption since January, 1983. Basalt flows from Kilauea have extruded over one cubic mile of lava, which currently covers about 48 square miles of land. These flows have travelled over seven miles to reach the ocean, covering highways, homes and entire subdivisions that were in their path.

Description Dotsadd Descriptive Hotspots To Your Images Transparent

Columbia River Flood Basalts: The Columbia River Flood Basalts are an extensive sequence of stacked lava flows that reach a cumulative thickness of up to 6000 feet. The outcrops in the foreground and in the distance of this photo are all made up of layered basalt flows. Although basalt is typically a dark black rock, it often weathers to a yellow-brown color similar to the rocks shown here. Public domain image by Williamborg.

Columbia River Flood Basalts Map: A map of the area underlain by the Columbia River Flood Basalts in Washington, Oregon, and Idaho. The area shown is what has not yet been eroded away - the original extent of these basalt flows was much greater. Over 300 individual flows have been identified, and several hundred meters of basalt underlies much of the area shown in the map above. Map copyright by Geology.com and MapResources.com.

Plumes & Hotspots Below Continents

The third basalt-forming environment is a continental environment where a mantle plume or hotspot delivers enormous amounts of basaltic lava through the continental crust and up to Earth's surface. These eruptions can be from either vents or fissures. They have produced the largest basalt flows on the continents. The eruptions can occur repeatedly over millions of years, producing layer after layer of basalt stacked in a vertical sequence (see outcrop photo).

The Columbia River Flood Basalts in Washington, Oregon, and Idaho are an example of extensive flood basalts on land (see map below). Other examples include the Emeishan Traps of China, the Deccan Traps of India, the Keweenawan Lavas of the Lake Superior region, the Etendeka Basalts of Namibia, the Karroo Basalts of South Africa, and the Siberian Traps of Russia. (The word 'traps' is derived from the Swedish word for 'stairs,' which describes the outcrop profile of these layered basalt deposits, as shown in the outcrop photo.)

Rock & Mineral Kits: Get a rock, mineral, or fossil kit to learn more about Earth materials. The best way to learn about rocks is to have specimens available for testing and examination.

The Roman theatre: (left) in Bosra, Syria. The dark building stone is basalt. Image copyright iStockphoto / Steve Estvanik.
Basalt paving stones: (right) on a city street in Rome, Italy. Basalt pavers were often used in areas close to volcanoes. Image copyright iStockphoto / Giovanni Rinaldi.

Uses of Basalt

Basalt is used for a wide variety of purposes. It is most commonly crushed for use as an aggregate in construction projects. Crushed basalt is used for road base, concrete aggregate, asphalt pavement aggregate, railroad ballast, filter stone in drain fields, and may other purposes. Basalt is also cut into dimension stone. Thin slabs of basalt are cut and sometimes polished for use as floor tiles, building veneer, monuments, and other stone objects.

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We have seen how to create hypertext link using text and we also learnt how to use images in our webpages. Now, we will learn how to use images to create hyperlinks.

Example

It's simple to use an image as hyperlink. We just need to use an image inside hyperlink at the place of text as shown below −

This will produce the following result, where you can click on the images to reach to the home page of Tutorials Point.

This was the simplest way of creating hyperlinks using images. Next we will see how we can create Mouse-Sensitive Image Links.

Mouse-Sensitive Images

The HTML and XHTML standards provides a feature that lets you embed many different links inside a single image. You can create different links on the single image based on different coordinates available on the image. Once different links are attached to different coordinates, we can click different parts of the image to open target documents. Such mouse-sensitive images are known as image maps.

There are two ways to create image maps −

• Server-side image maps − This is enabled by the ismap attribute of the <img> tag and requires access to a server and related image-map processing applications.

• Client-side image maps − This is created with the usemap attribute of the <img> tag, along with corresponding <map> and <area> tags.

Server-Side Image Maps

Here you simply put your image inside a hyper link and use ismap attribute which makes it special image and when the user clicks some place within the image, the browser passes the coordinates of the mouse pointer along with the URL specified in the <a> tag to the web server. The server uses the mouse-pointer coordinates to determine which document to deliver back to the browser.

When ismap is used, the href attribute of the containing <a> tag must contain the URL of a server application like a cgi or PHP script etc. to process the incoming request based on the passed coordinates.

The coordinates of the mouse position are screen pixels counted from the upper-left corner of the image, beginning with (0,0). The coordinates, preceded by a question mark, are added to the end of the URL.

For example, if a user clicks 20 pixels over and 30 pixels down from the upper-left corner of the following image −

Which has been generated by the following code snippet −

Then the browser sends the following search parameters to the web server which can be processed by ismap.cgi script or map file and you can link whatever documents you like to these coordinates −

Description Dotsadd Descriptive Hotspots To Your Images Online

This way you can assign different links to different coordinates of the image and when those coordinates are clicked, you can open corresponding linked document. To learn more about ismap attribute, you can check How to use Image ismap?

Note − You will learn CGI programming when you will study Perl programming. You can write your script to process these passed coordinates using PHP or any other script as well. For now, let's concentrate on learning HTML and later you can revisit this section.

Client-Side Image Maps

Description Dotsadd Descriptive Hotspots To Your Images High Resolution

Client side image maps are enabled by the usemap attribute of the <img /> tag and defined by special <map> and <area> extension tags.

The image that is going to form the map is inserted into the page using the <img /> tag as a normal image, except it carries an extra attribute called usemap. The value of the usemap attribute is the value which will be used in a <map> tag to link map and image tags. The <map> along with <area> tags define all the image coordinates and corresponding links.

The <area> tag inside the map tag, specifies the shape and the coordinates to define the boundaries of each clickable hotspot available on the image. Here's an example from the image map −

Fl studio 11 3 for maclasopasonic. This will produce the following result −

Coordinate System

Description Dotsadd Descriptive Hotspots To Your Images Free

The actual value of coords is totally dependent on the shape in question. Here is a summary, to be followed by detailed examples −

• rect = x₁ , y₁ , x₂ , y₂

  x₁ and y₁ are the coordinates of the upper left corner of the rectangle; x₂ and y₂ are the coordinates of the lower right corner.

• circle = x_c , y_c , radius

  x_c and y_c are the coordinates of the center of the circle, and radius is the circle's radius. A circle centered at 200,50 with a radius of 25 would have the attribute coords = '200,50,25'

• poly = x₁ , y₁ , x₂ , y₂ , x₃ , y₃ , .. x_n , y_n

  The various x-y pairs define vertices (points) of the polygon, with a 'line' being drawn from one point to the next point. A diamond-shaped polygon with its top point at 20,20 and 40 pixels across at its widest points would have the attribute coords = '20,20,40,40,20,60,0,40'.

All coordinates are relative to the upper-left corner of the image (0,0). Dmg file opener windows. Each shape has a related URL. You can use any image software to know the coordinates of different positions.