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I am so pissed off right now, and this is why:


This is a mapping application that we are customizing for a client. They have a format of data called RPF that ESRI MapObjects is particularly bad at cacheing. However, we found an open source project called OpenMap that handles RPF data very well. So it should be a whiz-bang process to create a custom MobObjects layer (the MapObjects API supports this) that uses the OpenMap code to spit out images. Making a small application that did nothing but spit out images given a path to RPF data and the extents of the image was nothing, simple task. Writing custom MapObjects layers is also not a big deal, we do it all the time.l


Typically, a map extent is defined as the min/max latitude and longitude. OpenMap on the other hand expects a center latitude and longitude, along with a map scale. Fine, whatever, except it completely ignores any concept of aspect ratio! But let's ignore that, let's just calculate the damn scale... wait, you CAN'T because a monitor's pixel-per-inch ratio is not fixed!

So, after much trial and error, I've come up with something that is a reasonable scale factor... I think. Panning the map left-right is good, panning it up-down is okay, but if you pan it diagonally you get this freaking fracturing of the image.

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I hate mapping software. It's all written like junk or is several thousand gigabytes large.

I pity you for having to deal with it.

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Original post by Ravuya
I hate mapping software. It's all written like junk or is several thousand gigabytes large.

I pity you for having to deal with it.

You're dead right. The problem is that there are very few computer scientists and computer engineers working on GIS software. It's all GIS analysts that just picked up programming as they went along. Of course, this means that they think VB is the ultimate programming language...

I'm writing my own map renderer, also. I haven't started to optimize it yet, but it's already outperforming ArcIMS by about 50 fold.

I might even end up writing my own spatial querying system, I have a couple of ideas on how graphics hardware might be useful for cutting several minute long queries down to a few milliseconds.

as for my map problem above, I have mostly fixed it. There are still a few artifacts, but they are mostly random, probably attributable to round-off error, and this is a government contract anyway. "Close enough for..." you get the point.

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