setting boundaries for small-scale maps

[Joe LeMonnier]

I get an error( IRangeMapError: The map is too big) when I zoom in and crop an area smaller than a single degree.

Mac OS HighSierra
Geocart 3.2.1 Mac 10.10

[Atarimaster]

Yes, I’ve noticed that, too – Geocart seems to be limited to areas with a size of at least 1 × 1 degree.
In my case, that wasn’t much of a problem, I simply worked with a map that was larger than I needed in Geocart, and cropped it afterwards in a graphics application (that I needed anyway to finish the map). I can understand that this isn’t a good solution depending on what you actually want to do, but it worked for me.

[daan]

Working at large scales has always been problematic in Geocart 3. The fact that I haven’t heard complaints about this before suggests it’s not used much at those scales.

I actually put a fair amount of work into this recently, reworking the problematic areas. I’m not finished yet.

There is no hard limit such as “one degree”. When you will have a problem depends on interactions between the projection, nominal scale, boundaries, and more obscure factors.

Apologies for the trouble.
— daan

[Atarimaster]

There is no hard limit such as “one degree”. When you will have a problem depends on interactions between the projection, nominal scale, boundaries, and more obscure factors.

Okay.
I have to admit that I didn’t test that thoroughly. On one occasion, I got the error message Joe mentioned a few times and it stopped when I entered an area of 1 × 1 degree size. So I jumped to conclusions and thought that there is a hard limit.

By the way, that was really the only occasion that I tried working at those scales.

Kind regards,
Tobias

[Joe LeMonnier]

I work at scales less than 1 x 1 degree at least once a month. Usually in about .1 x .1 degrees. That's not small at all when you are using topography. Most of the US is covered by 1/3 arc data, so someone must be working at these scales.

I'm pretty sure that Geocart in earlier versions did handle these scales

[daan]

All right, all right, all right. I’ll work on that now.


— daan

[Joe LeMonnier]

Is there any progress here? I keep trying to crop to less than a single degree and get very mixed results. At least once a month I need to crop to about a tenth-degree square .

[daan]

Hello Joe. Sorry you are having trouble with this. Can you confirm that you are on 3.3.5?

I do still see anomalies sometimes. I’ve been able to construct maps all the way down to the scope of a city block, but it’s not reliable. I need to figure out a way to deal with this without compromising the generality that permits arbitrarily bounded, fragmented maps.

— daan

[daan]

Here is an example of a 1:1,000 map representing a small area in Amsterdam less than 150 meters north/south. I can get to these scales reliably by stepping up the scale and reducing the map extent alternately. It’s cumbersome. Problems crop up when the map’s extent becomes tiny (such as, less than a pixel) at the scale you’re trying to render at.

— daan

Amsterdam Blocks.jpg (57.69 KiB) Viewed 22315 times