The graphic you refer to caught my interest so I went to the website (
https://landartgenerator.org/index.html) to learn more about how this was created.
The website has a page with a variety of other .pdf graphics, which do open correctly on the iPhone, see this page:
Together with communities, the Land Art Generator Initiative (LAGI) designs and deploys solar power and other renewable energy installations as beautiful places for people and economic development drivers.
landartgenerator.org
However the specific graphic you have selected is not included on that page for some reason. It is described on this page, which is where you obtained the link to the .pdf itself:
Summary To meet the target of net-zero by 2050 we will need to deploy 1.4 million square kilometers of renewable energy landscapes and 488 thousand square kilometers of renewable energy oceanscapes. More than 80% of this area will consist of "the space between"—the grassland between rows of...
landartgenerator.org
I am guessing that the difference here may be at least in part due to the resolution and ultimate size of the image. The link above states that "in the
full-resolution PDF version you can zoom in on every city". I'm not sure I can actually get that to work on my computer, when I try to zoom to that level of detail it doesn't seem to actually get to that fine resolution. But the file itself is probably different than the other .pdf files on the website, in how it is built up to contain all of the embedded data, and that is probably why it is not working on an iPhone. It is not a 'normal' .pdf, I think.
By the way, that is a terrific website. I appreciate your bringing attention to it.