if i want to put background bitmaps,and how big is the background bitmaps and how is the background bitmaps?thank you

I think the background map has to be in standard windows bmp format. It is best if the pixels in the image have the same resolution both in x and y dimension, and oriented with north up. I don't know if there is a size limitation. For this reason I like to use a projected image with a known pixel spacing in meters. If you do use a projected image, you must be careful to determine if there is a grid convergence, and rotate the image appropriately. For example, for the US you can download images that are projected in UTM, with a resolution of 1 or 4 meters per pixel. Using a grid convergense utility I can find the grid declination (usually about 1 degree or so) and I rotate the image in an editing program, then save it as windows bmp. If it is 1 meter data, in SGX I set the scale to 100 (pixels per 100 meters). If you have 1 known lat / long pair for a point in the image, you can move the image left right/ up down until the known point is at the correct lat/long. This completes the calibration of the image. SGX has a UTM to lat/long converter in it, whcih can help on this.scott s..

thank you for your answer ,but i have more questions ,so can you give me your MSN?

You can post your questions here -- that way any one can help, and if I or anyone else makes a mistake it is more likely to be corrected.scott s..

i didn't understand your say so much,sorry ,because it 's hard to understand ,can your use picture to explain to me?thank you very much

help me guys ,i don't know ,please use picture to explain to me ,thank you

Hello Vincent,If you indicate your native language, perhaps someone who speaks it could help you to understand.Best regards.Luis

my native language is chinese

I believe that you are our first Chinese-speaking member. Welcome to our little community.I would ask all those who reply to Vincent's questions to please make your replies as simple, yet detailed, as possible so as to help him understand. Please include as many images as needed.Vincent, please try to make your questions very detailed so that everyone can understand what you wish to do.Again, welcome.Best regards.Luis

LuisFelizTirado thank you ,can you give me your MSN?i want to talk with you in MSN,can i ?????????????