The Florida lake chart pack

Okeechobee is its own kind of day. The chart polygon for it measures 1,372.3 square kilometers, 339,102 acres, close to eight times the size of the next largest water the pack carries, which is Lake George at 175.4 square kilometers. Out in the middle of something that wide the far shore stops working as a reference and you are running on a course and a chart. Most days are not that day. Most days are Lake Istokpoga at 96.3 square kilometers, or Lake Tohopekaliga at 75.1, or a county ramp on water with no name on it at all, where the whole question is which way the channel runs out of the cove and how much you have over the flat before it.

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The pack draws 13,643 charted water bodies. Of those, 3,160 carry a name, and 347 named lakes are larger than a square kilometer. Every outline comes from the USGS National Hydrography Dataset, so a cove has its actual edge rather than a rounded-off blue shape.

What the pack carries, and where it stands among the 48

Of the 48 state packs, this one ranks fourth by charted water bodies at 13,643. It ranks sixth by named water at 3,160, and fifth by named lakes larger than a square kilometer at 347. Those three rankings together describe a state pack that is heavy at both ends.

At the top end it carries a single body of water of 1,372.3 square kilometers. At the other end it carries thousands you could run around in an afternoon in a jon boat, which is where the gap between 13,643 and 3,160 comes from. Most of the water in this pack has no name recorded for it. It is still drawn, still has an edge, and is still on the screen at a ramp with no bars on the phone.

The count is useful for one practical reason. If you fish small water, the thing that decides whether a chart app is worth carrying is not whether it has Okeechobee. It is whether the twelve acre pond behind the orange grove is a shape on the screen or an empty space between two roads.

LakeCharted surface area
Lake Okeechobee1,372 km² (339,102 acres)
Lake George175 km² (43,342 acres)
Lake Kissimmee127 km² (31,308 acres)
Lake Apopka125 km² (30,888 acres)
Mud Bay125 km² (30,789 acres)
Lake Istokpoga96 km² (23,796 acres)
Lake Tohopekaliga75 km² (18,558 acres)
Lake Harris74 km² (18,360 acres)
Crescent Lake69 km² (17,100 acres)
East Lake Tohopekaliga47 km² (11,713 acres)
Lake Seminole42 km² (10,453 acres)
Lake Griffin38 km² (9,439 acres)

The twelve largest named lakes the Florida pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 13,643 charted water bodies in all, 3,160 of them named, and 347 named lakes larger than one square kilometer.

Where the lake shapes come from

The nautical charts cover the coast, the intracoastal and the navigable rivers. The water bodies in this pack come from the USGS National Hydrography Dataset, which draws each lake's shoreline and carries its name. Of the 48 state lake packs, Minnesota is the one that also adds depth, as Minnesota DNR contour lines drawn on its lakes.

The outline gives the cove and the point their real shape, and that shape is what this pack puts on the chart. Lake Okeechobee also has depth: NOAA's electronic charts cover the lake itself, and those depth areas are in Helm's Florida East Coast pack.

A lake sits at whatever level it is being held at

The outline on the chart is the charted extent of the lake, not today's shoreline. The surface is a separate question, and on water held behind a dam that question was answered by somebody in an office this month. Pull the lake down a foot and the bottom has not moved anywhere. The distance between it and your keel has.

The creek channel running out of a cove is the thing to find, because it is in the same place at any level, and the shoulders on either side of it are what come up to meet you when the water is being held low. A ramp that is fine at full pool can have you idling a long way out with the level down.

The lakes that are not impounded move too, just on rain rather than on a schedule. Either way the practice is the same. Know the shape from the chart, know what the level is doing on the day you launch, and put the two together at the ramp rather than out at the far end of the lake.

The biggest water the pack names

Lake Okeechobee is the largest named lake the pack carries, at 1,372.3 square kilometers or 339,102 acres. Add the next nineteen largest named lakes in the pack together and they come to 1,245.6 square kilometers, still short of it.

Below Okeechobee the sizes tighten fast. Lake George is 175.4 square kilometers, 43,342 acres. Then Lake Kissimmee at 126.7 and Lake Apopka at 125.0, close enough that somebody who runs both would not call either one the bigger lake. Four tenths of a square kilometer under Apopka is Mud Bay at 124.6, which is a fair reminder that the names arrive from the hydrography dataset as they were recorded, and not everything at that size has the word lake in it.

Two of the twenty come out identical. Lake Worth and Blackjack Lake both measure 29.6 square kilometers, 7,314 acres, with Orange Lake two tenths behind at 29.4. Higher up the list, Lake Tohopekaliga at 75.1 is a little over half again the size of East Lake Tohopekaliga at 47.4, and Lake Harris at 74.3 sits within a square kilometer of the larger of that pair. Lake Istokpoga at 96.3 is bigger than any of them.

One thing worth knowing about how the packs are cut. They are cut to a box rather than to a state line, so a lake near the Georgia or Alabama boundary sits in this pack and in the neighboring pack as well. That is on purpose. Working out which side of a survey line your water falls on is not a thing you should have to do before you can download a chart.

The state lake packs draw lake shorelines from the USGS National Hydrography Dataset, and a reservoir sits at whatever level it is being held at that week. Treat the shape as a guide, keep a lookout, and verify locally.

Common questions

Does Lake Okeechobee have depth data, or only an outline?

It has depth in Helm's Florida East Coast pack. NOAA's electronic charts cover the lake itself, and that pack carries those depth areas and works on the device with no signal once it is downloaded. The Florida lake pack carries Okeechobee's outline, 1,372.3 square kilometers or 339,102 acres, drawn from the USGS National Hydrography Dataset.

How many lakes does the Florida chart pack cover?

It draws 13,643 charted water bodies, which is fourth among the 48 state packs. Of those, 3,160 carry a name, sixth of the 48, and 347 named lakes are larger than a square kilometer, fifth of the 48. The rest are the small ponds and backwaters, drawn from the same hydrography outlines as the big water.

If a lake sits on the Georgia or Alabama line, which pack carries it?

Both of them, in most cases. The packs are cut to a box rather than to the state line, so water near the boundary appears in this pack and in the neighboring state pack as well. Lake Seminole, at 42.3 square kilometers in this pack, is the sort of water that can show up in more than one. Download the pack covering the water you actually run and the line stops being your problem.

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