How to access a specific polygon in a shapefile by using a polygon id?

Question

I have a shapefile created by QGIS which has 25 polygons. I need to access each polygon by using a polygon id. I am using a java application to access these polygons. Please let me know any good tutorials to begin with.

Thanks in advance, Hasala.

Answer 1

If you want to handle it by yourself you have to read the specification provided by ESRI for shapefile. Here you can find it. But remember shapefile may not be a continuous stream of meaningful bytes so to find out where the information of the ith polygon (or any other shape) is located in the .shp file you have to first look at the .shx file.