I would like to search for the specific buildings (polyhouse in my case) on the map like the one shown here
Are there any free options available which can give me lat and lng of such shapes/features in specified area?
This isn't really an answer, but it is funny that I just saw an article today about this problem. Maybe it will lead you in the right direction.
Terrapattern, a visual search engine for satellite imagery, released this week by a team of artists and geographers at Carnegie Mellon University. It is Google’s “reverse image-search” tool for maps, basically: Click on a spot you find interesting, and Terrapattern will show you other spots on the map like it.
Looks promising, but...
Right now, Terrapattern only covers four American cities: Pittsburgh, Detroit, San Francisco and New York City. Terrapattern is so computing-hungry that it is effectively a proof of concept right now, at least for a team of artists working with less than $35,000. Each metro region takes about 10 gigabytes of RAM—not storage, but active memory.
If it is true that regions can use upwards of 10gb of active memory, then it isn't likely you'll find an easy or free solution right now.
DigitalGlobe offers a GBDX service that lets you deploy your object detection algorithms against the worlds largest satellite image archive: http://developer.digitalglobe.com/gbdx/
I think their free developer tier includes some algorithms that would help you get started. Getting acurrate building footprints with a fully automated algorithm is tough though!
Disclaimer: used to work at DigitalGlobe