Dasein, what is ready-to-hand within-the-world is desevered* and given directionality, depending upon the degree of transparency that is possible for concernful circumspection.
When we let entities within-the-world be encountered in the way which is constitutive for Being-in-the-world, we 'give them space'. This 'giving space', which we also call 'making room' for them,1 consists in freeing the ready-to-hand for its spatiality. As a way of discovering and presenting a possible totality of spaces determined by involvements, this making-room is what makes possible one's factical orientation at the time. In concerning itself circumspectively with the world, Dasein can move things around or out of the way or 'make room' for them [um—, weg—, und "einraumen"] only because making-room—understood as an existentiale—belongs to its Being-in-the-world. But neither the region previously discovered nor in general the current spatiality is explicitly in view. In itself it is present [zugegen] for circumspection in the inconspicuousness of those ready-to-hand things in which that circumspection is concernfully absorbed. With Being-in-the-world, space is proximally discovered in this spatiality. On the basis of the spatiality thus discovered, space itself becomes accessible for cognition.
Space is not in the subject, nor is the world in space. Space is rather 'in' the world in so far as space has been disclosed by that Being-in-the-world which is constitutive for Dasein. Space is not to be found in the subject, nor does the subject observe the world 'as if' that world were in a space; but the 'subject' (Dasein), if well understood ontologically, is spatial. And because Dasein is spatial in the way we have described, space shows itself as a priori. This term does not mean anything like previously belonging to a subject which is proximally still worldless and which emits a space out of itself. Here "apriority" means the previousness with which space has been encountered (as a region) whenever the ready-to-hand is encountered environmentally.
The spatiality of what we proximally encounter in circumspection can become a theme for circumspection itself, as well as a task for calculation  and measurement, as in building and surveying. Such thematization of the spatiality of the environment is still predominantly an act of circumspection by which space in itself already comes into view in a certain way. The space which thus shows itself can be studied purely by looking at it, if one gives up what was formerly the only possibility of access to it—circumspective calculation. When space is 'intuited formally', the pure
1 Both 'Raum-geben' (our 'giving space') and 'Einräumen' (our 'making room') are often used in the metaphorical sense of 'yielding', 'granting', or 'making concessions' . 'Einräumen' may also be used for 'arranging' furniture, 'moving it in', or 'stowing it away'.