Is our brand too close to a registered trade mark?

We would like to register a trade mark for our company. Some initial searching has turned up another word mark which seems somewhat similar to our brand. The owner of the registered TM is a surveying firm & consultancy in Austin, whereas we are a Californian company developing software for GIS applications.

How do we determine if our brand is too close to the other mark which is already registered? Thank you for your response in advance!