There are many free databases available for patent mapping. Generally we do patent mapping for two issues.
1. To prove that the patent is Valid/Invalid
2. To prove that the claim is Valid/Invalid.
Whatever be the case, If you want the free databases to search the patents around the world.. Go for http://www.irossco.com/patentsearching.htm. This website contains the links for all free databases.
If you want to make your mapping in a secure and easier way. Go for paid databases which comprising of patents through out the world.
I would recommend you to go for Thomson Innovation database, as it consists of quadrilateral database and also comprising of the business search along with literature search databases as the additional option. Hope this helps :)
Complementing Balamurugan's answer, Thomson Innovation is really a good base, but it is expensive. Above the free databases, I prefer Espacenet (EPO) search tool, which brings data from more than 90 patent offices around the world, however it has limitations in data export.
I have used both (Thomson Inn and Espacenet) for many years with success.
Espacenet does not provide analysis tools, I prefer him Patentscope the WIPO (https://patentscope.wipo.int/search/) for easy analysis. But I especially recommend The Lens (https://www.lens.org) which is for me the best free tool for mapping. For the advanced patent mapping, use more sophisticated tools, so paying as Orbit Questel, Thomson Innovation or Relecura.
Please evaluate the same, hope some are free. You can use get some information from my paper "Patinformatics – An Emerging Scientific Discipline" as well.
The processing of bibliographic data of patents is of great help in the extraction of indicators of innovation and development, with this we can identify people, companies and countries more prominent in certain branches of technology, we can identify the life cycle of the technology, we can identify new themes for the development of a certain technology, key patents for a technology, and in this, patent office sites help us, as sites of institutions dedicated to these purposes. Every day new things are published in this sense and the sites improve their benefits. The ones I consult the most are: Patentlens(https://www.lens.org/lens/structured-search) y patentinspiration(https://app.patentinspiration.com/), también son buenos patenscope(https://patentscope.wipo.int/search/en/search.jsf) y uno nuevo para mi patentsview(www.patentsview.org).
These are all free as I am Cuban, I do not have money to consult others, but these are very useful for me in my daily work.
En español:
El procesamiento de los datos bibliográficos de las patentes es de gran ayuda en la extracción de indicadores de innovación y desarrollo, con ello podemos identificar tanto personas, empresas como países más destacadas en determinadas ramas de la tecnología, podemos identificar el ciclo de vida de la tecnología, podemos identificar temáticas nuevas de desarrollo de determinada tecnología, patentes claves de una tecnología y en ello nos ayudan sitios de oficinas de patentes, como sitios de instituciones dedicadas a estos fines. Todos los días se publican nuevas cosas en este sentido y los sitios mejoran sus prestaciones. Los que yo más consulto son : Patentlens(https://www.lens.org/lens/structured-search) y patentinspiration(https://app.patentinspiration.com/), también son buenos patenscope(https://patentscope.wipo.int/search/en/search.jsf) y uno nuevo para mi patentsview(www.patentsview.org).
Estos todos son gratis como soy cubano no tengo dinero para consultar otros, pero estos me sirven bastante en mi trabajo diario.