The Webcam Snagger


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Downloads and saves still images from static web cams, or any static images. This is designed for occasional use rather than the means of continually collecting image as that is handled in the Image Service, or alternatively by another little program of mine called Immage Grabber.

The webcam snagger is on the View menu.

The opening screen looks like this.

Setting up a Capture

Before you can set up a capture you need to have the details to hand of where the web cam stores its images. Generally you can find these by looking at the source code of a web page provided you understand the basics of the code of course. Most code is sort of loosely English based (You might not agree with that!) and what you will be looking for is probably either a GIF or a JPG file. It is possible that it could be a PNG file but not very likely (but getting more so since I first wrote this).

Alternatively you can get the ones I already have set up for myself, and can ask for assistance for new ones.
Let’s take a look at a specific example – Popocatepetl in Mexico. You can follow this through with me if you like. This is the web address of the cam and there is a sample of the image below (which also links you to the site).

Right click the page and choose ‘Copy image location’ in Firefox, or ‘Copy Image URL’ in Chrome, or ‘Copy Image Address’ in Opera and if you have Internet Explorer get yourself a proper browser 🙂

Being serious in IE you have to right click the image, scroll down to properties and then in the pop-up window scrape the image address and then copy it using Ctrl+C or right-click the highlighted text and select Copy.

This is what you should have in your clipboard: http://www.cenapred.unam.mx/images/popo1.jpg

Most of the items you need to set up a capture can be found on the right hand side of the screen.

First you need to set the base URL for the image, which is the address you have just copied. Click on ‘Set Source Base’ and paste the image address into the box.

Because the image is a direct link in this case there is no problem with copying in the whole of the address including the filename.

When you click on OK you will find that the iamge address has been entered in the top left hand corner of the form where it says Source, and at the bottom left you now have 2 red and 2 green blocks.

To complete the task all the blocks have to be green.

Next click on the ‘Set Store Folder’ button. This is where you select where the images that are downloaded are to be placed. Clicking the button opens a standard Windows folder browser. Select ther location and when you click OK you will see you now have 3 green blocks.

You do not need to set the source file in this instance as it has been included in the URL, so click on the check box which says ‘File in URL’

The ‘Set Source File’ button is disabled and we have another green label, in fact you now have 4 greens so your landing gear is down and locked.

You could save what you have now and it would work, but there are a couple of other tweaks that it is best to attend to. By default the system creates a file name that is just the date and time. That is not too helpful if you have more than one type of image going into the same folder. You need to set a prefix, so since you are setting up Popocatapetl just type Popo in the box under ‘Store file prefix’.

Finally you need to set the time. If a web page refreshes every 5 minutes then there is no point in collecting an image every minute. You would want to change the timing to 300 seconds. Enter 300 in the Camera click box or use the arrows to change the value.

When the ‘camera clicks’ an image will be stored. If you just want to view what is going on the check the ‘View Only’ box at the bottom right of the screen. Images will now be downloaded, but not stored. This can be refined further. Click the Store Tab, top right.

If the counter here is greater than 0 then if View Only is switch on the image will be downloaded but will only be stored every nth ‘click’. So if you have a 300 second timing and 6 in the store box, the image will be downloaded every 5 minutes and stored once an hour if View Only is on. If View Only is off the image will be stores every 5 minutes.

So with everything set up you now need to save these settings. Click ‘Save Camera’ on the toolbar and enter a name in the box for this. How about Popocatapetl since that is what we are setting up?

The default ‘lapse’ time in the system is 60 seconds, but you can set it to anything from 2 to 21600. (6 hours if you can’t be bothered to work that out). Yes it will snap every 2 seconds and there are cams out there where you may wish to use that.

‘Snap Now’ will store an image if you are in view only mode, or if the timer has not been started. This always stores the image.

To recall a setting use ‘Load Camera’. Once you have selected the setting and loaded it you can change the timings if you wish.

To start automatically saving image click ‘Start Timer’

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