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OpenWebGIS is online Geographic Information System

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OpenWebGIS: old maps overlay on the modern ones
openwebgis

In OpenWebGIS the editing function of the image layer bounds (borders) has been redesigned. Image layer is generated by adding images (format jpg, png, etc.) on the map. This function with transparency changing of the image and other layers can have many practical applications, such as for historians - the overlay of old maps of the area to modern ones for analysis of the terrain changes, for treasure hunters – identifying of locations with potentially interesting search opportunities for intact artifacts in abandoned settlements (non-existent on modern maps).




Similar functions of course already exist in other software, but the main advantage of OpenWebGIS, is that this and other functions can be used online without downloading and installing on your PC any additional software. Now the window with editing settings of the image layer bounds can be (after selecting the menu item Interface-Switch to interface drag) moved at any convenient for the user place on the screen.
The user can apply the image on the map in two ways:

1. Changing of appropriate editbox (input fields) of geographical coordinates of the lower left corner and upper right corner;

2. Dragging of the picture after clicking on it and stretching the edges of the picture (this happens after you click 'Edit by click and drag').

If the first method is basically clear, the second one has the features you need to know to use the functions effectively.
After pressing the 'Edit by click and drag' button to drag the image to any location on the map you must click (left mouse button) once on the appropriate image, then following the moving cursor the image will move, after moving it to the desired place click again and the movement will be over. To change the image bounds (expansion and contraction) you need to move the mouse cursor to the image edge. After that the cursor form will change and you can start moving it. If the cursor is near the right edge, depending on the cursor movement direction the image will either decrease or increase in the width. If the cursor is near the bottom edge, depending on the cursor movement direction the image will either decrease or increase in the height. If the cursor is to the left side, the picture will only increase in the width to the right, if the cursor is near the top edge, the picture will only increase downwards in the height. In all mentioned cases during the cursor movement the coordinates values automatically change in the editboxes. These coordinates values correspond to the current position and size of the image.
Important: To use this function, all vector layers lying above the image layer, must be disabled (invisible), i.e. ticked off in front of them in the list of map layers.