Author: blogger

Georeferencing & Cad Drawing

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To describe it now, georeferencing is a process of taking an image and assigning geographic coordinates to it or to georeference something means to define its existence in the physical space by establishing a relation between raster or vector images to map projections or coordinate systems. When data from different sources need to be compiled and used in any GIS application, it is important to have a common referencing system. This is brought about by using various georeferencing techniques.

The process georeferencing

Georeferencing usually refers to the method by which locations in raster and vector GIS files are related to real earth-surface positions.

Raster data is often taken by scanning maps or collecting aerial photographs and satellite images. Scanned map datasets usually do not have any spatial reference information. The location information delivered with aerial photography and satellite imagery might be inadequate and the data need not align correctly with some other data you possess.

In order to use some raster datasets in conjunction with other spatial data, you sometimes need to align or georeference them to a map coordinate system which can be defines using a map projection to display the curved surface of the earth on a flat surface.

Georeference a raster dataset means defining its location using map coordinates and assigning a coordinate system. This process allows it to be viewed, queried, and analyzed in comparison with other geographic data.

How can you georeference a raster dataset?

Add the raster dataset to be aligned to your projected data in ArcMap.

Add control points that connect known raster dataset positions to the map coordinate positions.

When the alignment becomes correct, save the georeferencing information (registration) for further use.

Though GIS users are familiar with the term ‘georeferening’, many of the CAD users are not much aware of the term and the use of gereferencing in CAD.

Why is it wanted?

A raster image has no particular size as it is made up of pixels. The size of the vectorised CAD/GIS drawing is determined by the raster’s pixel dimensions, without georeferencing. The image resolution (DPI) can determine this. This image size usually has no relationship with the size of the drawing that the raster represents.

A CAD file is usually drawn in a local coordinate system and depicts spatial information which can be drawn accurately without being fixed to a higher global coordinate system. However, when the drawing needs to be related to a higher level in a mapping context with data from many different sources, tools in ArcMap can easily reposition a CAD file and integrate it into that higher level without altering the CAD file.

First thing is to find out two points on the CAD file that matches with two points in the map for which we can use the Georeferencing toolbar in ArcMap.

Different tools on the toolbar can support different workflows and below listed is an easy way to describe georeferencing a CAD file.

First step is to load the CAD drawing and ensure that one of the CAD feature layers are listed in the drop down menu of the georeferencing toolbar.

Zooming to the place roughly on the map where the CAD drawing is to be related is the next step. You can use the ‘fit to display’ tool on the menu to fix the CAD file in the map frame.

ArcMap snapping helps accurate placement of the CAD file which makes precise selection of control points based on existing geometry. Use the ‘rotate’ tool if the CAD file needs to be rotated to get the drawing nearer to its final position. This enables easy picking of control points.

You can use the interactive scaling tool also for the above mentioned reason.

Now when you select the ‘update georeferencing’ option, this creates a .WLD file that will be read from now on to put your CAD file in the right place.

Finally, the coordinates are always adjusted into this physical place. Now you can select a equivalent system for your CAD drawing so that you can assign or project its coordinates with reference to the map or during any other geospatial operation.

Regards
SBL Geomatics

http://www.sblgis.com/cad-services.aspx

By:Navya

Info On Dwg Drawing And Spider Web Drawings

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DWG – “drawing” is a format used for storing two and three dimensional design data and metadata. It is the native format for several CAD packages including AutoCAD. The DWG format is probably the most widely used format for CAD drawings.

DWG Drawing to PDF Converter allows you convert DWG to PDF, DXF to PDF directly without need of AutoCAD, it converts DWG and DXF files into vector PDF files, quick and easily. There are several claims to control of the DWG format. It is Autodesk who designs, defines, and iterates the DWG format as the native format for their CAD applications. The DWG format is probably the most widely used format for CAD drawings. Autodesk estimates that in 1998 there were in excess of two billion DWG files in existence. There are several claims to control of the DWG format. DWG Drawing to PDF Converter supports a wide variety of versions of DWG and DXF files, it supports DXF or DWG files. PDF converter is convenient and easy to operate, and DWG and DXF files can be directly dragged from Windows Explorer and converted fast.

DWG is a file format.
Applicant is not the exclusive source of files with the format name DWG.
Applicant does not control the use of DWG by others, either as a trademark or as a file format name.
The submitted survey does not reflect recognition of DWG as a trademark, since no distinction was made between use as a trademark and use as the name of a file format.
To tackle “spider web drawing means you must be capable of drawing straight lines. A spider web is not so easy to draw as it looks. If you are thinking of doing drawings of spider webs, take a look around outside to see if you can spot a good looking spider web. Do a quick, rough sketch outside then transfer it once you have a firm surface to draw on. After a bit of practice, spider web drawings were quite easy. For Drawing Corner Spider Web, you have to take your pencil and on the top of the page, about two inches from the right start drawing a line to 2 inches below the right top corner. The line should loop down and have points.
Draw straight lines from the points in your first line to the corner.
Make lines parallel to your fist line going all the way up. You should have 5 or 6 lines.
For Drawing Full Spider Web, Get a paper and make a cross on it, try to make both lines a similar length (using a ruler will help)
Draw diagonal lines through the center, dividing the paper up from 4 to 8 sections.
Start connecting the lines with inverted arcs, this is an arc), from the inside out.

Once you have reached the end of the web, elongate the diagonal lines, this will make it look like it has supports. Draw a spider by making a fuzzy ball, then drawing legs (eight of them) on your web. This spider web drawing in a tree looks quite attractive, a bit like a sailboat. The straight lines were probably the hardest part. You have to be careful while drawings the threads of web link up together neatly and spaced fairly accurately. Some spiders take pride in their homes obviously.

Louis Vuitton is Drawing Graffiti

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Louis Vuitton is Drawing Graffiti

Inspired from the art of design and with the development of fashion industry, now natural free Graffiti culture has become a brand new aesthetic phenomenon which is being concerned day by day, and as one of the mainstream of fashion culture. Like the current released Louis Vuitton Stephen Sprouse Tribute Collection in Spring/Summer 2009.

As for the brand new Louis Vuitton collection, Marc Jacobs the head designer of LV group made a command, saying that “in the last days, I was told that I can not make any change from the classic monogram style, therefore, I tried my best to design just follow the rule. Until the season, I realized that I have to make something new. I hope I would be younger, cooler and more stylish. I clearly know what I really want so that I take the advantage of Graffiti style of Stephen”.

As a fact, since it has released, there comes with so many topics about fashion. Without any question, the Graffiti idea is another great success. At the same time, Terry Richardson screened series of photos of the collection that published on Harpers Bazaar, Jan 2009, among which Marc Jacobs showed his stature with Graffiti all over the body. Very eye-catching!

Since 2001, the House of Louis Vuitton first cooperated with Stephen Sprouse and created the Graffiti collection. While, it is a great pity that Stephen Sprouse died in 2004. Till now, five years have past, Marc Jacobs released the collection again in order to momorialize the friend. In the collection, the colors of the Graffiti print against the classic Monogram Canvas background are all neon (lime green, shocking pink and bright orange) and there is also Rose-tattoo collection inspired by Sprouses past work.. Louis Vuitton is now drawing graffiti, what about you?

What is Graffiti? It is recognized that Graffiti origined from Philadelphia and Pennsylvania of America in 1966. At the first beginning, graffiti is simply a symbol. Graffiti writers during that time just tag their nickname, doorplate number and the like. From 1971 to 1974, more and more writers began to make effort on the tyle and effect of the words. Maybe you cannot describe very well toward the Graffiti, we have to admit that now Graffiti has developed into a form of art which has received a great deal of recent attention.

Besides Louis Vuitton, there still are so many brands which have special favor toward Graffiti.

In a word, there is a special relationship between art and fashion industry. More or less, they effect each other. The Louis Vuitton Monogram Graffiti style is such a classic style.

Drawing A Decorative Space In Your Garden With Pergolas And Arbors

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These additional designs come in a variety of metals but the most common is Vinyl because of its sturdy and effective nature. Arbors and pergolas are two types of garden structures that can greatly contribute to the overall design of your landscape. Arbors and pergolas add an element of interest to a yard or garden by drawing the eye upward. Whether functional or ornamental, there are many ways you can utilize these structures to enhance your landscape design.

Materials for arbors and pergolas vary greatly and can include wood, vinyl, or metal. Vinyl pergolas and arbor is a great maintenance free option that won’t require painting or staining. Vinyl is also resistant to rot and decay, and will last much longer than wood. Vinyl typically costs more than wood, but the longevity of the product may pay off in the long run.

Arbors and pergolas can be either functional or purely ornamental. If using an arbor for a functional purpose, consider adding a bench or swing to create a cozy nook for sitting and enjoying your garden. Large pergolas can be used as an overhead cover for a deck or patio. Arbors on the other hand are used to focus particular spots, decorate a pathway or even provide an entry way to a special zone.

This is the reason they have grown extremely popular today for homeowners particularly who are always on a look out for garden areas that boost the vitality of their home. Garden arbors and many other garden decoration mediums are available today that visually enhance the beauty of the space apart from the basic visual delights offered by trees, plants, grass, etc.

These decoration accessories include fountains, bird tops, planter boxes, pergolas etc, but the most vital in these are garden arbors. In short, garden arbors add a decorative as well as purposeful element to yards and gardens. They allow you to increase the size of your garden upward, and they create a focal point that draws the eye toward a particular area of interest. Garden arbors are an inexpensive and easy way to improve and spice up the look of any outdoor space.

Drawing Tablet for PC

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Many people who enjoy creating graphics with their computer seek to invest in a drawing tablet for PC. These devices are preferred over a regular computer mouse. They offer a number of benefits that a mouse is unable to provide. If you want to be able to create better looking graphics through a method that is similar to drawing with a pen and paper, then you should check into getting a graphics tablet of your own. Read on to learn more about the different types of tablets as well as the advantages of using them over a mouse.

The most common type of drawing tablet for the PC is one that connects to your computer with a USB cord. The tablet features a pad that is similar to a notebook. The device that is used for drawing is a stylus that is either wired or wireless, depending on the model that you choose. The biggest benefit of these tablets is the realistic look and feel to actually drawing. As you move the styles across the pad, the lines show up on the computer screen, just as they would if you were really creating a picture using a pen and paper. This is something that a mouse cannot offer in any way.

Also, a graphics tablet is sensitive to the location as well as the amount of pressure you use when drawing. You are not restricted by the size of the pad because the pen can detect exactly where you are in reference to the computer screen. If you press down hard with the pen, there will be a thicker, darker line created on the screen. A mouse cannot offer this feature. If you were drawing with a mouse, you’d have to change the settings before your lines would show up darker.

Another type of drawing tablet for PC that you can purchase offers most of the functionality in the writing instrument. The tablet that you would draw on is the monitor itself. This removes the barrier between a separate pad and the computer screen. This can make it easier to create images, since you will be drawing directly on the screen where the image will be displayed. This is yet another benefit over a normal computer mouse, as you cannot draw directly onto the screen with it.

A computer mouse can come into handy in many areas. Thanks to the invention of a drawing tablet for PC, creating images is no longer one of them. It is much easier to design graphics when you have the ability to use a device that closely resembles a pen and paper. A computer mouse can offer a lot, but it cannot come close to the advancements provided with a graphics tablet. Anyone with artistic interests should consider purchasing a tablet in order to create computer graphics.

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